root/arch/mips/math-emu/cp1emu.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * cp1emu.c: a MIPS coprocessor 1 (FPU) instruction emulator
 *
 * MIPS floating point support
 * Copyright (C) 1994-2000 Algorithmics Ltd.
 *
 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 2000  MIPS Technologies, Inc.
 *
 * A complete emulator for MIPS coprocessor 1 instructions.  This is
 * required for #float(switch) or #float(trap), where it catches all
 * COP1 instructions via the "CoProcessor Unusable" exception.
 *
 * More surprisingly it is also required for #float(ieee), to help out
 * the hardware FPU at the boundaries of the IEEE-754 representation
 * (denormalised values, infinities, underflow, etc).  It is made
 * quite nasty because emulation of some non-COP1 instructions is
 * required, e.g. in branch delay slots.
 *
 * Note if you know that you won't have an FPU, then you'll get much
 * better performance by compiling with -msoft-float!
 */
#include <linux/sched.h>
#include <linux/debugfs.h>
#include <linux/percpu-defs.h>
#include <linux/perf_event.h>

#include <asm/branch.h>
#include <asm/inst.h>
#include <asm/ptrace.h>
#include <asm/signal.h>
#include <linux/uaccess.h>

#include <asm/cpu-info.h>
#include <asm/processor.h>
#include <asm/fpu_emulator.h>
#include <asm/fpu.h>
#include <asm/mips-r2-to-r6-emul.h>

#include "ieee754.h"

/* Function which emulates a floating point instruction. */

static int fpu_emu(struct pt_regs *, struct mips_fpu_struct *,
        mips_instruction);

static int fpux_emu(struct pt_regs *,
        struct mips_fpu_struct *, mips_instruction, void __user **);

/* Control registers */

#define FPCREG_RID      0       /* $0  = revision id */
#define FPCREG_FCCR     25      /* $25 = fccr */
#define FPCREG_FEXR     26      /* $26 = fexr */
#define FPCREG_FENR     28      /* $28 = fenr */
#define FPCREG_CSR      31      /* $31 = csr */

/* convert condition code register number to csr bit */
const unsigned int fpucondbit[8] = {
        FPU_CSR_COND,
        FPU_CSR_COND1,
        FPU_CSR_COND2,
        FPU_CSR_COND3,
        FPU_CSR_COND4,
        FPU_CSR_COND5,
        FPU_CSR_COND6,
        FPU_CSR_COND7
};

/* (microMIPS) Convert certain microMIPS instructions to MIPS32 format. */
static const int sd_format[] = {16, 17, 0, 0, 0, 0, 0, 0};
static const int sdps_format[] = {16, 17, 22, 0, 0, 0, 0, 0};
static const int dwl_format[] = {17, 20, 21, 0, 0, 0, 0, 0};
static const int swl_format[] = {16, 20, 21, 0, 0, 0, 0, 0};

/*
 * This functions translates a 32-bit microMIPS instruction
 * into a 32-bit MIPS32 instruction. Returns 0 on success
 * and SIGILL otherwise.
 */
static int microMIPS32_to_MIPS32(union mips_instruction *insn_ptr)
{
        union mips_instruction insn = *insn_ptr;
        union mips_instruction mips32_insn = insn;
        int func, fmt, op;

        switch (insn.mm_i_format.opcode) {
        case mm_ldc132_op:
                mips32_insn.mm_i_format.opcode = ldc1_op;
                mips32_insn.mm_i_format.rt = insn.mm_i_format.rs;
                mips32_insn.mm_i_format.rs = insn.mm_i_format.rt;
                break;
        case mm_lwc132_op:
                mips32_insn.mm_i_format.opcode = lwc1_op;
                mips32_insn.mm_i_format.rt = insn.mm_i_format.rs;
                mips32_insn.mm_i_format.rs = insn.mm_i_format.rt;
                break;
        case mm_sdc132_op:
                mips32_insn.mm_i_format.opcode = sdc1_op;
                mips32_insn.mm_i_format.rt = insn.mm_i_format.rs;
                mips32_insn.mm_i_format.rs = insn.mm_i_format.rt;
                break;
        case mm_swc132_op:
                mips32_insn.mm_i_format.opcode = swc1_op;
                mips32_insn.mm_i_format.rt = insn.mm_i_format.rs;
                mips32_insn.mm_i_format.rs = insn.mm_i_format.rt;
                break;
        case mm_pool32i_op:
                /* NOTE: offset is << by 1 if in microMIPS mode. */
                if ((insn.mm_i_format.rt == mm_bc1f_op) ||
                    (insn.mm_i_format.rt == mm_bc1t_op)) {
                        mips32_insn.fb_format.opcode = cop1_op;
                        mips32_insn.fb_format.bc = bc_op;
                        mips32_insn.fb_format.flag =
                                (insn.mm_i_format.rt == mm_bc1t_op) ? 1 : 0;
                } else
                        return SIGILL;
                break;
        case mm_pool32f_op:
                switch (insn.mm_fp0_format.func) {
                case mm_32f_01_op:
                case mm_32f_11_op:
                case mm_32f_02_op:
                case mm_32f_12_op:
                case mm_32f_41_op:
                case mm_32f_51_op:
                case mm_32f_42_op:
                case mm_32f_52_op:
                        op = insn.mm_fp0_format.func;
                        if (op == mm_32f_01_op)
                                func = madd_s_op;
                        else if (op == mm_32f_11_op)
                                func = madd_d_op;
                        else if (op == mm_32f_02_op)
                                func = nmadd_s_op;
                        else if (op == mm_32f_12_op)
                                func = nmadd_d_op;
                        else if (op == mm_32f_41_op)
                                func = msub_s_op;
                        else if (op == mm_32f_51_op)
                                func = msub_d_op;
                        else if (op == mm_32f_42_op)
                                func = nmsub_s_op;
                        else
                                func = nmsub_d_op;
                        mips32_insn.fp6_format.opcode = cop1x_op;
                        mips32_insn.fp6_format.fr = insn.mm_fp6_format.fr;
                        mips32_insn.fp6_format.ft = insn.mm_fp6_format.ft;
                        mips32_insn.fp6_format.fs = insn.mm_fp6_format.fs;
                        mips32_insn.fp6_format.fd = insn.mm_fp6_format.fd;
                        mips32_insn.fp6_format.func = func;
                        break;
                case mm_32f_10_op:
                        func = -1;      /* Invalid */
                        op = insn.mm_fp5_format.op & 0x7;
                        if (op == mm_ldxc1_op)
                                func = ldxc1_op;
                        else if (op == mm_sdxc1_op)
                                func = sdxc1_op;
                        else if (op == mm_lwxc1_op)
                                func = lwxc1_op;
                        else if (op == mm_swxc1_op)
                                func = swxc1_op;

                        if (func != -1) {
                                mips32_insn.r_format.opcode = cop1x_op;
                                mips32_insn.r_format.rs =
                                        insn.mm_fp5_format.base;
                                mips32_insn.r_format.rt =
                                        insn.mm_fp5_format.index;
                                mips32_insn.r_format.rd = 0;
                                mips32_insn.r_format.re = insn.mm_fp5_format.fd;
                                mips32_insn.r_format.func = func;
                        } else
                                return SIGILL;
                        break;
                case mm_32f_40_op:
                        op = -1;        /* Invalid */
                        if (insn.mm_fp2_format.op == mm_fmovt_op)
                                op = 1;
                        else if (insn.mm_fp2_format.op == mm_fmovf_op)
                                op = 0;
                        if (op != -1) {
                                mips32_insn.fp0_format.opcode = cop1_op;
                                mips32_insn.fp0_format.fmt =
                                        sdps_format[insn.mm_fp2_format.fmt];
                                mips32_insn.fp0_format.ft =
                                        (insn.mm_fp2_format.cc<<2) + op;
                                mips32_insn.fp0_format.fs =
                                        insn.mm_fp2_format.fs;
                                mips32_insn.fp0_format.fd =
                                        insn.mm_fp2_format.fd;
                                mips32_insn.fp0_format.func = fmovc_op;
                        } else
                                return SIGILL;
                        break;
                case mm_32f_60_op:
                        func = -1;      /* Invalid */
                        if (insn.mm_fp0_format.op == mm_fadd_op)
                                func = fadd_op;
                        else if (insn.mm_fp0_format.op == mm_fsub_op)
                                func = fsub_op;
                        else if (insn.mm_fp0_format.op == mm_fmul_op)
                                func = fmul_op;
                        else if (insn.mm_fp0_format.op == mm_fdiv_op)
                                func = fdiv_op;
                        if (func != -1) {
                                mips32_insn.fp0_format.opcode = cop1_op;
                                mips32_insn.fp0_format.fmt =
                                        sdps_format[insn.mm_fp0_format.fmt];
                                mips32_insn.fp0_format.ft =
                                        insn.mm_fp0_format.ft;
                                mips32_insn.fp0_format.fs =
                                        insn.mm_fp0_format.fs;
                                mips32_insn.fp0_format.fd =
                                        insn.mm_fp0_format.fd;
                                mips32_insn.fp0_format.func = func;
                        } else
                                return SIGILL;
                        break;
                case mm_32f_70_op:
                        func = -1;      /* Invalid */
                        if (insn.mm_fp0_format.op == mm_fmovn_op)
                                func = fmovn_op;
                        else if (insn.mm_fp0_format.op == mm_fmovz_op)
                                func = fmovz_op;
                        if (func != -1) {
                                mips32_insn.fp0_format.opcode = cop1_op;
                                mips32_insn.fp0_format.fmt =
                                        sdps_format[insn.mm_fp0_format.fmt];
                                mips32_insn.fp0_format.ft =
                                        insn.mm_fp0_format.ft;
                                mips32_insn.fp0_format.fs =
                                        insn.mm_fp0_format.fs;
                                mips32_insn.fp0_format.fd =
                                        insn.mm_fp0_format.fd;
                                mips32_insn.fp0_format.func = func;
                        } else
                                return SIGILL;
                        break;
                case mm_32f_73_op:    /* POOL32FXF */
                        switch (insn.mm_fp1_format.op) {
                        case mm_movf0_op:
                        case mm_movf1_op:
                        case mm_movt0_op:
                        case mm_movt1_op:
                                if ((insn.mm_fp1_format.op & 0x7f) ==
                                    mm_movf0_op)
                                        op = 0;
                                else
                                        op = 1;
                                mips32_insn.r_format.opcode = spec_op;
                                mips32_insn.r_format.rs = insn.mm_fp4_format.fs;
                                mips32_insn.r_format.rt =
                                        (insn.mm_fp4_format.cc << 2) + op;
                                mips32_insn.r_format.rd = insn.mm_fp4_format.rt;
                                mips32_insn.r_format.re = 0;
                                mips32_insn.r_format.func = movc_op;
                                break;
                        case mm_fcvtd0_op:
                        case mm_fcvtd1_op:
                        case mm_fcvts0_op:
                        case mm_fcvts1_op:
                                if ((insn.mm_fp1_format.op & 0x7f) ==
                                    mm_fcvtd0_op) {
                                        func = fcvtd_op;
                                        fmt = swl_format[insn.mm_fp3_format.fmt];
                                } else {
                                        func = fcvts_op;
                                        fmt = dwl_format[insn.mm_fp3_format.fmt];
                                }
                                mips32_insn.fp0_format.opcode = cop1_op;
                                mips32_insn.fp0_format.fmt = fmt;
                                mips32_insn.fp0_format.ft = 0;
                                mips32_insn.fp0_format.fs =
                                        insn.mm_fp3_format.fs;
                                mips32_insn.fp0_format.fd =
                                        insn.mm_fp3_format.rt;
                                mips32_insn.fp0_format.func = func;
                                break;
                        case mm_fmov0_op:
                        case mm_fmov1_op:
                        case mm_fabs0_op:
                        case mm_fabs1_op:
                        case mm_fneg0_op:
                        case mm_fneg1_op:
                                if ((insn.mm_fp1_format.op & 0x7f) ==
                                    mm_fmov0_op)
                                        func = fmov_op;
                                else if ((insn.mm_fp1_format.op & 0x7f) ==
                                         mm_fabs0_op)
                                        func = fabs_op;
                                else
                                        func = fneg_op;
                                mips32_insn.fp0_format.opcode = cop1_op;
                                mips32_insn.fp0_format.fmt =
                                        sdps_format[insn.mm_fp3_format.fmt];
                                mips32_insn.fp0_format.ft = 0;
                                mips32_insn.fp0_format.fs =
                                        insn.mm_fp3_format.fs;
                                mips32_insn.fp0_format.fd =
                                        insn.mm_fp3_format.rt;
                                mips32_insn.fp0_format.func = func;
                                break;
                        case mm_ffloorl_op:
                        case mm_ffloorw_op:
                        case mm_fceill_op:
                        case mm_fceilw_op:
                        case mm_ftruncl_op:
                        case mm_ftruncw_op:
                        case mm_froundl_op:
                        case mm_froundw_op:
                        case mm_fcvtl_op:
                        case mm_fcvtw_op:
                                if (insn.mm_fp1_format.op == mm_ffloorl_op)
                                        func = ffloorl_op;
                                else if (insn.mm_fp1_format.op == mm_ffloorw_op)
                                        func = ffloor_op;
                                else if (insn.mm_fp1_format.op == mm_fceill_op)
                                        func = fceill_op;
                                else if (insn.mm_fp1_format.op == mm_fceilw_op)
                                        func = fceil_op;
                                else if (insn.mm_fp1_format.op == mm_ftruncl_op)
                                        func = ftruncl_op;
                                else if (insn.mm_fp1_format.op == mm_ftruncw_op)
                                        func = ftrunc_op;
                                else if (insn.mm_fp1_format.op == mm_froundl_op)
                                        func = froundl_op;
                                else if (insn.mm_fp1_format.op == mm_froundw_op)
                                        func = fround_op;
                                else if (insn.mm_fp1_format.op == mm_fcvtl_op)
                                        func = fcvtl_op;
                                else
                                        func = fcvtw_op;
                                mips32_insn.fp0_format.opcode = cop1_op;
                                mips32_insn.fp0_format.fmt =
                                        sd_format[insn.mm_fp1_format.fmt];
                                mips32_insn.fp0_format.ft = 0;
                                mips32_insn.fp0_format.fs =
                                        insn.mm_fp1_format.fs;
                                mips32_insn.fp0_format.fd =
                                        insn.mm_fp1_format.rt;
                                mips32_insn.fp0_format.func = func;
                                break;
                        case mm_frsqrt_op:
                        case mm_fsqrt_op:
                        case mm_frecip_op:
                                if (insn.mm_fp1_format.op == mm_frsqrt_op)
                                        func = frsqrt_op;
                                else if (insn.mm_fp1_format.op == mm_fsqrt_op)
                                        func = fsqrt_op;
                                else
                                        func = frecip_op;
                                mips32_insn.fp0_format.opcode = cop1_op;
                                mips32_insn.fp0_format.fmt =
                                        sdps_format[insn.mm_fp1_format.fmt];
                                mips32_insn.fp0_format.ft = 0;
                                mips32_insn.fp0_format.fs =
                                        insn.mm_fp1_format.fs;
                                mips32_insn.fp0_format.fd =
                                        insn.mm_fp1_format.rt;
                                mips32_insn.fp0_format.func = func;
                                break;
                        case mm_mfc1_op:
                        case mm_mtc1_op:
                        case mm_cfc1_op:
                        case mm_ctc1_op:
                        case mm_mfhc1_op:
                        case mm_mthc1_op:
                                if (insn.mm_fp1_format.op == mm_mfc1_op)
                                        op = mfc_op;
                                else if (insn.mm_fp1_format.op == mm_mtc1_op)
                                        op = mtc_op;
                                else if (insn.mm_fp1_format.op == mm_cfc1_op)
                                        op = cfc_op;
                                else if (insn.mm_fp1_format.op == mm_ctc1_op)
                                        op = ctc_op;
                                else if (insn.mm_fp1_format.op == mm_mfhc1_op)
                                        op = mfhc_op;
                                else
                                        op = mthc_op;
                                mips32_insn.fp1_format.opcode = cop1_op;
                                mips32_insn.fp1_format.op = op;
                                mips32_insn.fp1_format.rt =
                                        insn.mm_fp1_format.rt;
                                mips32_insn.fp1_format.fs =
                                        insn.mm_fp1_format.fs;
                                mips32_insn.fp1_format.fd = 0;
                                mips32_insn.fp1_format.func = 0;
                                break;
                        default:
                                return SIGILL;
                        }
                        break;
                case mm_32f_74_op:      /* c.cond.fmt */
                        mips32_insn.fp0_format.opcode = cop1_op;
                        mips32_insn.fp0_format.fmt =
                                sdps_format[insn.mm_fp4_format.fmt];
                        mips32_insn.fp0_format.ft = insn.mm_fp4_format.rt;
                        mips32_insn.fp0_format.fs = insn.mm_fp4_format.fs;
                        mips32_insn.fp0_format.fd = insn.mm_fp4_format.cc << 2;
                        mips32_insn.fp0_format.func =
                                insn.mm_fp4_format.cond | MM_MIPS32_COND_FC;
                        break;
                default:
                        return SIGILL;
                }
                break;
        default:
                return SIGILL;
        }

        *insn_ptr = mips32_insn;
        return 0;
}

/*
 * Redundant with logic already in kernel/branch.c,
 * embedded in compute_return_epc.  At some point,
 * a single subroutine should be used across both
 * modules.
 */
int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
                  unsigned long *contpc)
{
        union mips_instruction insn = (union mips_instruction)dec_insn.insn;
        unsigned int fcr31;
        unsigned int bit = 0;
        unsigned int bit0;
        union fpureg *fpr;

        switch (insn.i_format.opcode) {
        case spec_op:
                switch (insn.r_format.func) {
                case jalr_op:
                        if (insn.r_format.rd != 0) {
                                regs->regs[insn.r_format.rd] =
                                        regs->cp0_epc + dec_insn.pc_inc +
                                        dec_insn.next_pc_inc;
                        }
                        fallthrough;
                case jr_op:
                        /* For R6, JR already emulated in jalr_op */
                        if (NO_R6EMU && insn.r_format.func == jr_op)
                                break;
                        *contpc = regs->regs[insn.r_format.rs];
                        return 1;
                }
                break;
        case bcond_op:
                switch (insn.i_format.rt) {
                case bltzal_op:
                case bltzall_op:
                        if (NO_R6EMU && (insn.i_format.rs ||
                            insn.i_format.rt == bltzall_op))
                                break;

                        regs->regs[31] = regs->cp0_epc +
                                dec_insn.pc_inc +
                                dec_insn.next_pc_inc;
                        fallthrough;
                case bltzl_op:
                        if (NO_R6EMU)
                                break;
                        fallthrough;
                case bltz_op:
                        if ((long)regs->regs[insn.i_format.rs] < 0)
                                *contpc = regs->cp0_epc +
                                        dec_insn.pc_inc +
                                        (insn.i_format.simmediate << 2);
                        else
                                *contpc = regs->cp0_epc +
                                        dec_insn.pc_inc +
                                        dec_insn.next_pc_inc;
                        return 1;
                case bgezal_op:
                case bgezall_op:
                        if (NO_R6EMU && (insn.i_format.rs ||
                            insn.i_format.rt == bgezall_op))
                                break;

                        regs->regs[31] = regs->cp0_epc +
                                dec_insn.pc_inc +
                                dec_insn.next_pc_inc;
                        fallthrough;
                case bgezl_op:
                        if (NO_R6EMU)
                                break;
                        fallthrough;
                case bgez_op:
                        if ((long)regs->regs[insn.i_format.rs] >= 0)
                                *contpc = regs->cp0_epc +
                                        dec_insn.pc_inc +
                                        (insn.i_format.simmediate << 2);
                        else
                                *contpc = regs->cp0_epc +
                                        dec_insn.pc_inc +
                                        dec_insn.next_pc_inc;
                        return 1;
                }
                break;
        case jalx_op:
                set_isa16_mode(bit);
                fallthrough;
        case jal_op:
                regs->regs[31] = regs->cp0_epc +
                        dec_insn.pc_inc +
                        dec_insn.next_pc_inc;
                fallthrough;
        case j_op:
                *contpc = regs->cp0_epc + dec_insn.pc_inc;
                *contpc >>= 28;
                *contpc <<= 28;
                *contpc |= (insn.j_format.target << 2);
                /* Set microMIPS mode bit: XOR for jalx. */
                *contpc ^= bit;
                return 1;
        case beql_op:
                if (NO_R6EMU)
                        break;
                fallthrough;
        case beq_op:
                if (regs->regs[insn.i_format.rs] ==
                    regs->regs[insn.i_format.rt])
                        *contpc = regs->cp0_epc +
                                dec_insn.pc_inc +
                                (insn.i_format.simmediate << 2);
                else
                        *contpc = regs->cp0_epc +
                                dec_insn.pc_inc +
                                dec_insn.next_pc_inc;
                return 1;
        case bnel_op:
                if (NO_R6EMU)
                        break;
                fallthrough;
        case bne_op:
                if (regs->regs[insn.i_format.rs] !=
                    regs->regs[insn.i_format.rt])
                        *contpc = regs->cp0_epc +
                                dec_insn.pc_inc +
                                (insn.i_format.simmediate << 2);
                else
                        *contpc = regs->cp0_epc +
                                dec_insn.pc_inc +
                                dec_insn.next_pc_inc;
                return 1;
        case blezl_op:
                if (!insn.i_format.rt && NO_R6EMU)
                        break;
                fallthrough;
        case blez_op:

                /*
                 * Compact branches for R6 for the
                 * blez and blezl opcodes.
                 * BLEZ  | rs = 0 | rt != 0  == BLEZALC
                 * BLEZ  | rs = rt != 0      == BGEZALC
                 * BLEZ  | rs != 0 | rt != 0 == BGEUC
                 * BLEZL | rs = 0 | rt != 0  == BLEZC
                 * BLEZL | rs = rt != 0      == BGEZC
                 * BLEZL | rs != 0 | rt != 0 == BGEC
                 *
                 * For real BLEZ{,L}, rt is always 0.
                 */
                if (cpu_has_mips_r6 && insn.i_format.rt) {
                        if ((insn.i_format.opcode == blez_op) &&
                            ((!insn.i_format.rs && insn.i_format.rt) ||
                             (insn.i_format.rs == insn.i_format.rt)))
                                regs->regs[31] = regs->cp0_epc +
                                        dec_insn.pc_inc;
                        *contpc = regs->cp0_epc + dec_insn.pc_inc +
                                dec_insn.next_pc_inc;

                        return 1;
                }
                if ((long)regs->regs[insn.i_format.rs] <= 0)
                        *contpc = regs->cp0_epc +
                                dec_insn.pc_inc +
                                (insn.i_format.simmediate << 2);
                else
                        *contpc = regs->cp0_epc +
                                dec_insn.pc_inc +
                                dec_insn.next_pc_inc;
                return 1;
        case bgtzl_op:
                if (!insn.i_format.rt && NO_R6EMU)
                        break;
                fallthrough;
        case bgtz_op:
                /*
                 * Compact branches for R6 for the
                 * bgtz and bgtzl opcodes.
                 * BGTZ  | rs = 0 | rt != 0  == BGTZALC
                 * BGTZ  | rs = rt != 0      == BLTZALC
                 * BGTZ  | rs != 0 | rt != 0 == BLTUC
                 * BGTZL | rs = 0 | rt != 0  == BGTZC
                 * BGTZL | rs = rt != 0      == BLTZC
                 * BGTZL | rs != 0 | rt != 0 == BLTC
                 *
                 * *ZALC varint for BGTZ &&& rt != 0
                 * For real GTZ{,L}, rt is always 0.
                 */
                if (cpu_has_mips_r6 && insn.i_format.rt) {
                        if ((insn.i_format.opcode == blez_op) &&
                            ((!insn.i_format.rs && insn.i_format.rt) ||
                             (insn.i_format.rs == insn.i_format.rt)))
                                regs->regs[31] = regs->cp0_epc +
                                        dec_insn.pc_inc;
                        *contpc = regs->cp0_epc + dec_insn.pc_inc +
                                dec_insn.next_pc_inc;

                        return 1;
                }

                if ((long)regs->regs[insn.i_format.rs] > 0)
                        *contpc = regs->cp0_epc +
                                dec_insn.pc_inc +
                                (insn.i_format.simmediate << 2);
                else
                        *contpc = regs->cp0_epc +
                                dec_insn.pc_inc +
                                dec_insn.next_pc_inc;
                return 1;
        case pop10_op:
        case pop30_op:
                if (!cpu_has_mips_r6)
                        break;
                if (insn.i_format.rt && !insn.i_format.rs)
                        regs->regs[31] = regs->cp0_epc + 4;
                *contpc = regs->cp0_epc + dec_insn.pc_inc +
                        dec_insn.next_pc_inc;

                return 1;
#ifdef CONFIG_CPU_CAVIUM_OCTEON
        case lwc2_op: /* This is bbit0 on Octeon */
                if ((regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt)) == 0)
                        *contpc = regs->cp0_epc + 4 + (insn.i_format.simmediate << 2);
                else
                        *contpc = regs->cp0_epc + 8;
                return 1;
        case ldc2_op: /* This is bbit032 on Octeon */
                if ((regs->regs[insn.i_format.rs] & (1ull<<(insn.i_format.rt + 32))) == 0)
                        *contpc = regs->cp0_epc + 4 + (insn.i_format.simmediate << 2);
                else
                        *contpc = regs->cp0_epc + 8;
                return 1;
        case swc2_op: /* This is bbit1 on Octeon */
                if (regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt))
                        *contpc = regs->cp0_epc + 4 + (insn.i_format.simmediate << 2);
                else
                        *contpc = regs->cp0_epc + 8;
                return 1;
        case sdc2_op: /* This is bbit132 on Octeon */
                if (regs->regs[insn.i_format.rs] & (1ull<<(insn.i_format.rt + 32)))
                        *contpc = regs->cp0_epc + 4 + (insn.i_format.simmediate << 2);
                else
                        *contpc = regs->cp0_epc + 8;
                return 1;
#else
        case bc6_op:
                /*
                 * Only valid for MIPS R6 but we can still end up
                 * here from a broken userland so just tell emulator
                 * this is not a branch and let it break later on.
                 */
                if  (!cpu_has_mips_r6)
                        break;
                *contpc = regs->cp0_epc + dec_insn.pc_inc +
                        dec_insn.next_pc_inc;

                return 1;
        case balc6_op:
                if (!cpu_has_mips_r6)
                        break;
                regs->regs[31] = regs->cp0_epc + 4;
                *contpc = regs->cp0_epc + dec_insn.pc_inc +
                        dec_insn.next_pc_inc;

                return 1;
        case pop66_op:
                if (!cpu_has_mips_r6)
                        break;
                *contpc = regs->cp0_epc + dec_insn.pc_inc +
                        dec_insn.next_pc_inc;

                return 1;
        case pop76_op:
                if (!cpu_has_mips_r6)
                        break;
                if (!insn.i_format.rs)
                        regs->regs[31] = regs->cp0_epc + 4;
                *contpc = regs->cp0_epc + dec_insn.pc_inc +
                        dec_insn.next_pc_inc;

                return 1;
#endif
        case cop0_op:
        case cop1_op:
                /* Need to check for R6 bc1nez and bc1eqz branches */
                if (cpu_has_mips_r6 &&
                    ((insn.i_format.rs == bc1eqz_op) ||
                     (insn.i_format.rs == bc1nez_op))) {
                        bit = 0;
                        fpr = &current->thread.fpu.fpr[insn.i_format.rt];
                        bit0 = get_fpr32(fpr, 0) & 0x1;
                        switch (insn.i_format.rs) {
                        case bc1eqz_op:
                                bit = bit0 == 0;
                                break;
                        case bc1nez_op:
                                bit = bit0 != 0;
                                break;
                        }
                        if (bit)
                                *contpc = regs->cp0_epc +
                                        dec_insn.pc_inc +
                                        (insn.i_format.simmediate << 2);
                        else
                                *contpc = regs->cp0_epc +
                                        dec_insn.pc_inc +
                                        dec_insn.next_pc_inc;

                        return 1;
                }
                /* R2/R6 compatible cop1 instruction */
                fallthrough;
        case cop2_op:
        case cop1x_op:
                if (insn.i_format.rs == bc_op) {
                        preempt_disable();
                        if (is_fpu_owner())
                                fcr31 = read_32bit_cp1_register(CP1_STATUS);
                        else
                                fcr31 = current->thread.fpu.fcr31;
                        preempt_enable();

                        bit = (insn.i_format.rt >> 2);
                        bit += (bit != 0);
                        bit += 23;
                        switch (insn.i_format.rt & 3) {
                        case 0: /* bc1f */
                        case 2: /* bc1fl */
                                if (~fcr31 & (1 << bit))
                                        *contpc = regs->cp0_epc +
                                                dec_insn.pc_inc +
                                                (insn.i_format.simmediate << 2);
                                else
                                        *contpc = regs->cp0_epc +
                                                dec_insn.pc_inc +
                                                dec_insn.next_pc_inc;
                                return 1;
                        case 1: /* bc1t */
                        case 3: /* bc1tl */
                                if (fcr31 & (1 << bit))
                                        *contpc = regs->cp0_epc +
                                                dec_insn.pc_inc +
                                                (insn.i_format.simmediate << 2);
                                else
                                        *contpc = regs->cp0_epc +
                                                dec_insn.pc_inc +
                                                dec_insn.next_pc_inc;
                                return 1;
                        }
                }
                break;
        }
        return 0;
}

/*
 * In the Linux kernel, we support selection of FPR format on the
 * basis of the Status.FR bit.  If an FPU is not present, the FR bit
 * is hardwired to zero, which would imply a 32-bit FPU even for
 * 64-bit CPUs so we rather look at TIF_32BIT_FPREGS.
 * FPU emu is slow and bulky and optimizing this function offers fairly
 * sizeable benefits so we try to be clever and make this function return
 * a constant whenever possible, that is on 64-bit kernels without O32
 * compatibility enabled and on 32-bit without 64-bit FPU support.
 */
static inline int cop1_64bit(struct pt_regs *xcp)
{
        if (IS_ENABLED(CONFIG_64BIT) && !IS_ENABLED(CONFIG_MIPS32_O32))
                return 1;
        else if (IS_ENABLED(CONFIG_32BIT) &&
                 !IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT))
                return 0;

        return !test_thread_flag(TIF_32BIT_FPREGS);
}

static inline bool hybrid_fprs(void)
{
        return test_thread_flag(TIF_HYBRID_FPREGS);
}

#define SIFROMREG(si, x)                                                \
do {                                                                    \
        if (cop1_64bit(xcp) && !hybrid_fprs())                          \
                (si) = (int)get_fpr32(&ctx->fpr[x], 0);                 \
        else                                                            \
                (si) = (int)get_fpr32(&ctx->fpr[(x) & ~1], (x) & 1);    \
} while (0)

#define SITOREG(si, x)                                                  \
do {                                                                    \
        if (cop1_64bit(xcp) && !hybrid_fprs()) {                        \
                unsigned int i;                                         \
                set_fpr32(&ctx->fpr[x], 0, si);                         \
                for (i = 1; i < ARRAY_SIZE(ctx->fpr[x].val32); i++)     \
                        set_fpr32(&ctx->fpr[x], i, 0);                  \
        } else {                                                        \
                set_fpr32(&ctx->fpr[(x) & ~1], (x) & 1, si);            \
        }                                                               \
} while (0)

#define SIFROMHREG(si, x)       ((si) = (int)get_fpr32(&ctx->fpr[x], 1))

#define SITOHREG(si, x)                                                 \
do {                                                                    \
        unsigned int i;                                                 \
        set_fpr32(&ctx->fpr[x], 1, si);                                 \
        for (i = 2; i < ARRAY_SIZE(ctx->fpr[x].val32); i++)             \
                set_fpr32(&ctx->fpr[x], i, 0);                          \
} while (0)

#define DIFROMREG(di, x)                                                \
        ((di) = get_fpr64(&ctx->fpr[(x) & ~(cop1_64bit(xcp) ^ 1)], 0))

#define DITOREG(di, x)                                                  \
do {                                                                    \
        unsigned int fpr, i;                                            \
        fpr = (x) & ~(cop1_64bit(xcp) ^ 1);                             \
        set_fpr64(&ctx->fpr[fpr], 0, di);                               \
        for (i = 1; i < ARRAY_SIZE(ctx->fpr[x].val64); i++)             \
                set_fpr64(&ctx->fpr[fpr], i, 0);                        \
} while (0)

#define SPFROMREG(sp, x) SIFROMREG((sp).bits, x)
#define SPTOREG(sp, x)  SITOREG((sp).bits, x)
#define DPFROMREG(dp, x)        DIFROMREG((dp).bits, x)
#define DPTOREG(dp, x)  DITOREG((dp).bits, x)

/*
 * Emulate a CFC1 instruction.
 */
static inline void cop1_cfc(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                            mips_instruction ir)
{
        u32 fcr31 = ctx->fcr31;
        u32 value = 0;

        switch (MIPSInst_RD(ir)) {
        case FPCREG_CSR:
                value = fcr31;
                pr_debug("%p gpr[%d]<-csr=%08x\n",
                         (void *)xcp->cp0_epc, MIPSInst_RT(ir), value);
                break;

        case FPCREG_FENR:
                if (!cpu_has_mips_r)
                        break;
                value = (fcr31 >> (FPU_CSR_FS_S - MIPS_FENR_FS_S)) &
                        MIPS_FENR_FS;
                value |= fcr31 & (FPU_CSR_ALL_E | FPU_CSR_RM);
                pr_debug("%p gpr[%d]<-enr=%08x\n",
                         (void *)xcp->cp0_epc, MIPSInst_RT(ir), value);
                break;

        case FPCREG_FEXR:
                if (!cpu_has_mips_r)
                        break;
                value = fcr31 & (FPU_CSR_ALL_X | FPU_CSR_ALL_S);
                pr_debug("%p gpr[%d]<-exr=%08x\n",
                         (void *)xcp->cp0_epc, MIPSInst_RT(ir), value);
                break;

        case FPCREG_FCCR:
                if (!cpu_has_mips_r)
                        break;
                value = (fcr31 >> (FPU_CSR_COND_S - MIPS_FCCR_COND0_S)) &
                        MIPS_FCCR_COND0;
                value |= (fcr31 >> (FPU_CSR_COND1_S - MIPS_FCCR_COND1_S)) &
                         (MIPS_FCCR_CONDX & ~MIPS_FCCR_COND0);
                pr_debug("%p gpr[%d]<-ccr=%08x\n",
                         (void *)xcp->cp0_epc, MIPSInst_RT(ir), value);
                break;

        case FPCREG_RID:
                value = boot_cpu_data.fpu_id;
                break;

        default:
                break;
        }

        if (MIPSInst_RT(ir))
                xcp->regs[MIPSInst_RT(ir)] = value;
}

/*
 * Emulate a CTC1 instruction.
 */
static inline void cop1_ctc(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                            mips_instruction ir)
{
        u32 fcr31 = ctx->fcr31;
        u32 value;
        u32 mask;

        if (MIPSInst_RT(ir) == 0)
                value = 0;
        else
                value = xcp->regs[MIPSInst_RT(ir)];

        switch (MIPSInst_RD(ir)) {
        case FPCREG_CSR:
                pr_debug("%p gpr[%d]->csr=%08x\n",
                         (void *)xcp->cp0_epc, MIPSInst_RT(ir), value);

                /* Preserve read-only bits.  */
                mask = boot_cpu_data.fpu_msk31;
                fcr31 = (value & ~mask) | (fcr31 & mask);
                break;

        case FPCREG_FENR:
                if (!cpu_has_mips_r)
                        break;
                pr_debug("%p gpr[%d]->enr=%08x\n",
                         (void *)xcp->cp0_epc, MIPSInst_RT(ir), value);
                fcr31 &= ~(FPU_CSR_FS | FPU_CSR_ALL_E | FPU_CSR_RM);
                fcr31 |= (value << (FPU_CSR_FS_S - MIPS_FENR_FS_S)) &
                         FPU_CSR_FS;
                fcr31 |= value & (FPU_CSR_ALL_E | FPU_CSR_RM);
                break;

        case FPCREG_FEXR:
                if (!cpu_has_mips_r)
                        break;
                pr_debug("%p gpr[%d]->exr=%08x\n",
                         (void *)xcp->cp0_epc, MIPSInst_RT(ir), value);
                fcr31 &= ~(FPU_CSR_ALL_X | FPU_CSR_ALL_S);
                fcr31 |= value & (FPU_CSR_ALL_X | FPU_CSR_ALL_S);
                break;

        case FPCREG_FCCR:
                if (!cpu_has_mips_r)
                        break;
                pr_debug("%p gpr[%d]->ccr=%08x\n",
                         (void *)xcp->cp0_epc, MIPSInst_RT(ir), value);
                fcr31 &= ~(FPU_CSR_CONDX | FPU_CSR_COND);
                fcr31 |= (value << (FPU_CSR_COND_S - MIPS_FCCR_COND0_S)) &
                         FPU_CSR_COND;
                fcr31 |= (value << (FPU_CSR_COND1_S - MIPS_FCCR_COND1_S)) &
                         FPU_CSR_CONDX;
                break;

        default:
                break;
        }

        ctx->fcr31 = fcr31;
}

/*
 * Emulate the single floating point instruction pointed at by EPC.
 * Two instructions if the instruction is in a branch delay slot.
 */

static int cop1Emulate(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
                struct mm_decoded_insn dec_insn, void __user **fault_addr)
{
        unsigned long contpc = xcp->cp0_epc + dec_insn.pc_inc;
        unsigned int cond, cbit, bit0;
        mips_instruction ir;
        int likely, pc_inc;
        union fpureg *fpr;
        u32 __user *wva;
        u64 __user *dva;
        u32 wval;
        u64 dval;
        int sig;

        /*
         * These are giving gcc a gentle hint about what to expect in
         * dec_inst in order to do better optimization.
         */
        if (!cpu_has_mmips && dec_insn.micro_mips_mode)
                unreachable();

        /* XXX NEC Vr54xx bug workaround */
        if (delay_slot(xcp)) {
                if (dec_insn.micro_mips_mode) {
                        if (!mm_isBranchInstr(xcp, dec_insn, &contpc))
                                clear_delay_slot(xcp);
                } else {
                        if (!isBranchInstr(xcp, dec_insn, &contpc))
                                clear_delay_slot(xcp);
                }
        }

        if (delay_slot(xcp)) {
                /*
                 * The instruction to be emulated is in a branch delay slot
                 * which means that we have to  emulate the branch instruction
                 * BEFORE we do the cop1 instruction.
                 *
                 * This branch could be a COP1 branch, but in that case we
                 * would have had a trap for that instruction, and would not
                 * come through this route.
                 *
                 * Linux MIPS branch emulator operates on context, updating the
                 * cp0_epc.
                 */
                ir = dec_insn.next_insn;  /* process delay slot instr */
                pc_inc = dec_insn.next_pc_inc;
        } else {
                ir = dec_insn.insn;       /* process current instr */
                pc_inc = dec_insn.pc_inc;
        }

        /*
         * Since microMIPS FPU instructios are a subset of MIPS32 FPU
         * instructions, we want to convert microMIPS FPU instructions
         * into MIPS32 instructions so that we could reuse all of the
         * FPU emulation code.
         *
         * NOTE: We cannot do this for branch instructions since they
         *       are not a subset. Example: Cannot emulate a 16-bit
         *       aligned target address with a MIPS32 instruction.
         */
        if (dec_insn.micro_mips_mode) {
                /*
                 * If next instruction is a 16-bit instruction, then
                 * it cannot be a FPU instruction. This could happen
                 * since we can be called for non-FPU instructions.
                 */
                if ((pc_inc == 2) ||
                        (microMIPS32_to_MIPS32((union mips_instruction *)&ir)
                         == SIGILL))
                        return SIGILL;
        }

emul:
        perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, xcp, 0);
        MIPS_FPU_EMU_INC_STATS(emulated);
        switch (MIPSInst_OPCODE(ir)) {
        case ldc1_op:
                dva = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] +
                                     MIPSInst_SIMM(ir));
                MIPS_FPU_EMU_INC_STATS(loads);

                if (!access_ok(dva, sizeof(u64))) {
                        MIPS_FPU_EMU_INC_STATS(errors);
                        *fault_addr = dva;
                        return SIGBUS;
                }
                if (__get_user(dval, dva)) {
                        MIPS_FPU_EMU_INC_STATS(errors);
                        *fault_addr = dva;
                        return SIGSEGV;
                }
                DITOREG(dval, MIPSInst_RT(ir));
                break;

        case sdc1_op:
                dva = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] +
                                      MIPSInst_SIMM(ir));
                MIPS_FPU_EMU_INC_STATS(stores);
                DIFROMREG(dval, MIPSInst_RT(ir));
                if (!access_ok(dva, sizeof(u64))) {
                        MIPS_FPU_EMU_INC_STATS(errors);
                        *fault_addr = dva;
                        return SIGBUS;
                }
                if (__put_user(dval, dva)) {
                        MIPS_FPU_EMU_INC_STATS(errors);
                        *fault_addr = dva;
                        return SIGSEGV;
                }
                break;

        case lwc1_op:
                wva = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] +
                                      MIPSInst_SIMM(ir));
                MIPS_FPU_EMU_INC_STATS(loads);
                if (!access_ok(wva, sizeof(u32))) {
                        MIPS_FPU_EMU_INC_STATS(errors);
                        *fault_addr = wva;
                        return SIGBUS;
                }
                if (__get_user(wval, wva)) {
                        MIPS_FPU_EMU_INC_STATS(errors);
                        *fault_addr = wva;
                        return SIGSEGV;
                }
                SITOREG(wval, MIPSInst_RT(ir));
                break;

        case swc1_op:
                wva = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] +
                                      MIPSInst_SIMM(ir));
                MIPS_FPU_EMU_INC_STATS(stores);
                SIFROMREG(wval, MIPSInst_RT(ir));
                if (!access_ok(wva, sizeof(u32))) {
                        MIPS_FPU_EMU_INC_STATS(errors);
                        *fault_addr = wva;
                        return SIGBUS;
                }
                if (__put_user(wval, wva)) {
                        MIPS_FPU_EMU_INC_STATS(errors);
                        *fault_addr = wva;
                        return SIGSEGV;
                }
                break;

        case cop1_op:
                switch (MIPSInst_RS(ir)) {
                case dmfc_op:
                        if (!cpu_has_mips_3_4_5 && !cpu_has_mips64)
                                return SIGILL;

                        /* copregister fs -> gpr[rt] */
                        if (MIPSInst_RT(ir) != 0) {
                                DIFROMREG(xcp->regs[MIPSInst_RT(ir)],
                                        MIPSInst_RD(ir));
                        }
                        break;

                case dmtc_op:
                        if (!cpu_has_mips_3_4_5 && !cpu_has_mips64)
                                return SIGILL;

                        /* copregister fs <- rt */
                        DITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
                        break;

                case mfhc_op:
                        if (!cpu_has_mips_r2_r6)
                                return SIGILL;

                        /* copregister rd -> gpr[rt] */
                        if (MIPSInst_RT(ir) != 0) {
                                SIFROMHREG(xcp->regs[MIPSInst_RT(ir)],
                                        MIPSInst_RD(ir));
                        }
                        break;

                case mthc_op:
                        if (!cpu_has_mips_r2_r6)
                                return SIGILL;

                        /* copregister rd <- gpr[rt] */
                        SITOHREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
                        break;

                case mfc_op:
                        /* copregister rd -> gpr[rt] */
                        if (MIPSInst_RT(ir) != 0) {
                                SIFROMREG(xcp->regs[MIPSInst_RT(ir)],
                                        MIPSInst_RD(ir));
                        }
                        break;

                case mtc_op:
                        /* copregister rd <- rt */
                        SITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
                        break;

                case cfc_op:
                        /* cop control register rd -> gpr[rt] */
                        cop1_cfc(xcp, ctx, ir);
                        break;

                case ctc_op:
                        /* copregister rd <- rt */
                        cop1_ctc(xcp, ctx, ir);
                        if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
                                return SIGFPE;
                        }
                        break;

                case bc1eqz_op:
                case bc1nez_op:
                        if (!cpu_has_mips_r6 || delay_slot(xcp))
                                return SIGILL;

                        likely = 0;
                        cond = 0;
                        fpr = &current->thread.fpu.fpr[MIPSInst_RT(ir)];
                        bit0 = get_fpr32(fpr, 0) & 0x1;
                        switch (MIPSInst_RS(ir)) {
                        case bc1eqz_op:
                                MIPS_FPU_EMU_INC_STATS(bc1eqz);
                                cond = bit0 == 0;
                                break;
                        case bc1nez_op:
                                MIPS_FPU_EMU_INC_STATS(bc1nez);
                                cond = bit0 != 0;
                                break;
                        }
                        goto branch_common;

                case bc_op:
                        if (delay_slot(xcp))
                                return SIGILL;

                        if (cpu_has_mips_4_5_r)
                                cbit = fpucondbit[MIPSInst_RT(ir) >> 2];
                        else
                                cbit = FPU_CSR_COND;
                        cond = ctx->fcr31 & cbit;

                        likely = 0;
                        switch (MIPSInst_RT(ir) & 3) {
                        case bcfl_op:
                                if (cpu_has_mips_2_3_4_5_r)
                                        likely = 1;
                                fallthrough;
                        case bcf_op:
                                cond = !cond;
                                break;
                        case bctl_op:
                                if (cpu_has_mips_2_3_4_5_r)
                                        likely = 1;
                                fallthrough;
                        case bct_op:
                                break;
                        }
branch_common:
                        MIPS_FPU_EMU_INC_STATS(branches);
                        set_delay_slot(xcp);
                        if (cond) {
                                /*
                                 * Branch taken: emulate dslot instruction
                                 */
                                unsigned long bcpc;

                                /*
                                 * Remember EPC at the branch to point back
                                 * at so that any delay-slot instruction
                                 * signal is not silently ignored.
                                 */
                                bcpc = xcp->cp0_epc;
                                xcp->cp0_epc += dec_insn.pc_inc;

                                contpc = MIPSInst_SIMM(ir);
                                ir = dec_insn.next_insn;
                                if (dec_insn.micro_mips_mode) {
                                        contpc = (xcp->cp0_epc + (contpc << 1));

                                        /* If 16-bit instruction, not FPU. */
                                        if ((dec_insn.next_pc_inc == 2) ||
                                                (microMIPS32_to_MIPS32((union mips_instruction *)&ir) == SIGILL)) {

                                                /*
                                                 * Since this instruction will
                                                 * be put on the stack with
                                                 * 32-bit words, get around
                                                 * this problem by putting a
                                                 * NOP16 as the second one.
                                                 */
                                                if (dec_insn.next_pc_inc == 2)
                                                        ir = (ir & (~0xffff)) | MM_NOP16;

                                                /*
                                                 * Single step the non-CP1
                                                 * instruction in the dslot.
                                                 */
                                                sig = mips_dsemul(xcp, ir,
                                                                  bcpc, contpc);
                                                if (sig < 0)
                                                        break;
                                                if (sig)
                                                        xcp->cp0_epc = bcpc;
                                                /*
                                                 * SIGILL forces out of
                                                 * the emulation loop.
                                                 */
                                                return sig ? sig : SIGILL;
                                        }
                                } else
                                        contpc = (xcp->cp0_epc + (contpc << 2));

                                switch (MIPSInst_OPCODE(ir)) {
                                case lwc1_op:
                                case swc1_op:
                                        goto emul;

                                case ldc1_op:
                                case sdc1_op:
                                        if (cpu_has_mips_2_3_4_5_r)
                                                goto emul;

                                        goto bc_sigill;

                                case cop1_op:
                                        goto emul;

                                case cop1x_op:
                                        if (cpu_has_mips_4_5_64_r2_r6)
                                                /* its one of ours */
                                                goto emul;

                                        goto bc_sigill;

                                case spec_op:
                                        switch (MIPSInst_FUNC(ir)) {
                                        case movc_op:
                                                if (cpu_has_mips_4_5_r)
                                                        goto emul;

                                                goto bc_sigill;
                                        }
                                        break;

                                bc_sigill:
                                        xcp->cp0_epc = bcpc;
                                        return SIGILL;
                                }

                                /*
                                 * Single step the non-cp1
                                 * instruction in the dslot
                                 */
                                sig = mips_dsemul(xcp, ir, bcpc, contpc);
                                if (sig < 0)
                                        break;
                                if (sig)
                                        xcp->cp0_epc = bcpc;
                                /* SIGILL forces out of the emulation loop.  */
                                return sig ? sig : SIGILL;
                        } else if (likely) {    /* branch not taken */
                                /*
                                 * branch likely nullifies
                                 * dslot if not taken
                                 */
                                xcp->cp0_epc += dec_insn.pc_inc;
                                contpc += dec_insn.pc_inc;
                                /*
                                 * else continue & execute
                                 * dslot as normal insn
                                 */
                        }
                        break;

                default:
                        if (!(MIPSInst_RS(ir) & 0x10))
                                return SIGILL;

                        /* a real fpu computation instruction */
                        sig = fpu_emu(xcp, ctx, ir);
                        if (sig)
                                return sig;
                }
                break;

        case cop1x_op:
                if (!cpu_has_mips_4_5_64_r2_r6)
                        return SIGILL;

                sig = fpux_emu(xcp, ctx, ir, fault_addr);
                if (sig)
                        return sig;
                break;

        case spec_op:
                if (!cpu_has_mips_4_5_r)
                        return SIGILL;

                if (MIPSInst_FUNC(ir) != movc_op)
                        return SIGILL;
                cond = fpucondbit[MIPSInst_RT(ir) >> 2];
                if (((ctx->fcr31 & cond) != 0) == ((MIPSInst_RT(ir) & 1) != 0))
                        xcp->regs[MIPSInst_RD(ir)] =
                                xcp->regs[MIPSInst_RS(ir)];
                break;
        default:
                return SIGILL;
        }

        /* we did it !! */
        xcp->cp0_epc = contpc;
        clear_delay_slot(xcp);

        return 0;
}

/*
 * Conversion table from MIPS compare ops 48-63
 * cond = ieee754dp_cmp(x,y,IEEE754_UN,sig);
 */
static const unsigned char cmptab[8] = {
        0,                      /* cmp_0 (sig) cmp_sf */
        IEEE754_CUN,            /* cmp_un (sig) cmp_ngle */
        IEEE754_CEQ,            /* cmp_eq (sig) cmp_seq */
        IEEE754_CEQ | IEEE754_CUN,      /* cmp_ueq (sig) cmp_ngl  */
        IEEE754_CLT,            /* cmp_olt (sig) cmp_lt */
        IEEE754_CLT | IEEE754_CUN,      /* cmp_ult (sig) cmp_nge */
        IEEE754_CLT | IEEE754_CEQ,      /* cmp_ole (sig) cmp_le */
        IEEE754_CLT | IEEE754_CEQ | IEEE754_CUN,        /* cmp_ule (sig) cmp_ngt */
};

static const unsigned char negative_cmptab[8] = {
        0, /* Reserved */
        IEEE754_CLT | IEEE754_CGT | IEEE754_CEQ,
        IEEE754_CLT | IEEE754_CGT | IEEE754_CUN,
        IEEE754_CLT | IEEE754_CGT,
        /* Reserved */
};


/*
 * Additional MIPS4 instructions
 */

#define DEF3OP(name, p, f1, f2, f3)                                     \
static union ieee754##p fpemu_##p##_##name(union ieee754##p r,          \
        union ieee754##p s, union ieee754##p t)                         \
{                                                                       \
        struct _ieee754_csr ieee754_csr_save;                           \
        s = f1(s, t);                                                   \
        ieee754_csr_save = ieee754_csr;                                 \
        s = f2(s, r);                                                   \
        ieee754_csr_save.cx |= ieee754_csr.cx;                          \
        ieee754_csr_save.sx |= ieee754_csr.sx;                          \
        s = f3(s);                                                      \
        ieee754_csr.cx |= ieee754_csr_save.cx;                          \
        ieee754_csr.sx |= ieee754_csr_save.sx;                          \
        return s;                                                       \
}

static union ieee754dp fpemu_dp_recip(union ieee754dp d)
{
        return ieee754dp_div(ieee754dp_one(0), d);
}

static union ieee754dp fpemu_dp_rsqrt(union ieee754dp d)
{
        return ieee754dp_div(ieee754dp_one(0), ieee754dp_sqrt(d));
}

static union ieee754sp fpemu_sp_recip(union ieee754sp s)
{
        return ieee754sp_div(ieee754sp_one(0), s);
}

static union ieee754sp fpemu_sp_rsqrt(union ieee754sp s)
{
        return ieee754sp_div(ieee754sp_one(0), ieee754sp_sqrt(s));
}

DEF3OP(madd, sp, ieee754sp_mul, ieee754sp_add, );
DEF3OP(msub, sp, ieee754sp_mul, ieee754sp_sub, );
DEF3OP(nmadd, sp, ieee754sp_mul, ieee754sp_add, ieee754sp_neg);
DEF3OP(nmsub, sp, ieee754sp_mul, ieee754sp_sub, ieee754sp_neg);
DEF3OP(madd, dp, ieee754dp_mul, ieee754dp_add, );
DEF3OP(msub, dp, ieee754dp_mul, ieee754dp_sub, );
DEF3OP(nmadd, dp, ieee754dp_mul, ieee754dp_add, ieee754dp_neg);
DEF3OP(nmsub, dp, ieee754dp_mul, ieee754dp_sub, ieee754dp_neg);

static int fpux_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
        mips_instruction ir, void __user **fault_addr)
{
        unsigned int rcsr = 0;  /* resulting csr */

        MIPS_FPU_EMU_INC_STATS(cp1xops);

        switch (MIPSInst_FMA_FFMT(ir)) {
        case s_fmt:{            /* 0 */

                union ieee754sp(*handler) (union ieee754sp, union ieee754sp, union ieee754sp);
                union ieee754sp fd, fr, fs, ft;
                u32 __user *va;
                u32 val;

                switch (MIPSInst_FUNC(ir)) {
                case lwxc1_op:
                        va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
                                xcp->regs[MIPSInst_FT(ir)]);

                        MIPS_FPU_EMU_INC_STATS(loads);
                        if (!access_ok(va, sizeof(u32))) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                *fault_addr = va;
                                return SIGBUS;
                        }
                        if (__get_user(val, va)) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                *fault_addr = va;
                                return SIGSEGV;
                        }
                        SITOREG(val, MIPSInst_FD(ir));
                        break;

                case swxc1_op:
                        va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
                                xcp->regs[MIPSInst_FT(ir)]);

                        MIPS_FPU_EMU_INC_STATS(stores);

                        SIFROMREG(val, MIPSInst_FS(ir));
                        if (!access_ok(va, sizeof(u32))) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                *fault_addr = va;
                                return SIGBUS;
                        }
                        if (put_user(val, va)) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                *fault_addr = va;
                                return SIGSEGV;
                        }
                        break;

                case madd_s_op:
                        if (cpu_has_mac2008_only)
                                handler = ieee754sp_madd;
                        else
                                handler = fpemu_sp_madd;
                        goto scoptop;
                case msub_s_op:
                        if (cpu_has_mac2008_only)
                                handler = ieee754sp_msub;
                        else
                                handler = fpemu_sp_msub;
                        goto scoptop;
                case nmadd_s_op:
                        if (cpu_has_mac2008_only)
                                handler = ieee754sp_nmadd;
                        else
                                handler = fpemu_sp_nmadd;
                        goto scoptop;
                case nmsub_s_op:
                        if (cpu_has_mac2008_only)
                                handler = ieee754sp_nmsub;
                        else
                                handler = fpemu_sp_nmsub;
                        goto scoptop;

                      scoptop:
                        SPFROMREG(fr, MIPSInst_FR(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        fd = (*handler) (fr, fs, ft);
                        SPTOREG(fd, MIPSInst_FD(ir));

                      copcsr:
                        if (ieee754_cxtest(IEEE754_INEXACT)) {
                                MIPS_FPU_EMU_INC_STATS(ieee754_inexact);
                                rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
                        }
                        if (ieee754_cxtest(IEEE754_UNDERFLOW)) {
                                MIPS_FPU_EMU_INC_STATS(ieee754_underflow);
                                rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
                        }
                        if (ieee754_cxtest(IEEE754_OVERFLOW)) {
                                MIPS_FPU_EMU_INC_STATS(ieee754_overflow);
                                rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
                        }
                        if (ieee754_cxtest(IEEE754_INVALID_OPERATION)) {
                                MIPS_FPU_EMU_INC_STATS(ieee754_invalidop);
                                rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
                        }

                        ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
                        if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
                                /*printk ("SIGFPE: FPU csr = %08x\n",
                                   ctx->fcr31); */
                                return SIGFPE;
                        }

                        break;

                default:
                        return SIGILL;
                }
                break;
        }

        case d_fmt:{            /* 1 */
                union ieee754dp(*handler) (union ieee754dp, union ieee754dp, union ieee754dp);
                union ieee754dp fd, fr, fs, ft;
                u64 __user *va;
                u64 val;

                switch (MIPSInst_FUNC(ir)) {
                case ldxc1_op:
                        va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
                                xcp->regs[MIPSInst_FT(ir)]);

                        MIPS_FPU_EMU_INC_STATS(loads);
                        if (!access_ok(va, sizeof(u64))) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                *fault_addr = va;
                                return SIGBUS;
                        }
                        if (__get_user(val, va)) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                *fault_addr = va;
                                return SIGSEGV;
                        }
                        DITOREG(val, MIPSInst_FD(ir));
                        break;

                case sdxc1_op:
                        va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
                                xcp->regs[MIPSInst_FT(ir)]);

                        MIPS_FPU_EMU_INC_STATS(stores);
                        DIFROMREG(val, MIPSInst_FS(ir));
                        if (!access_ok(va, sizeof(u64))) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                *fault_addr = va;
                                return SIGBUS;
                        }
                        if (__put_user(val, va)) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                *fault_addr = va;
                                return SIGSEGV;
                        }
                        break;

                case madd_d_op:
                        if (cpu_has_mac2008_only)
                                handler = ieee754dp_madd;
                        else
                                handler = fpemu_dp_madd;
                        goto dcoptop;
                case msub_d_op:
                        if (cpu_has_mac2008_only)
                                handler = ieee754dp_msub;
                        else
                                handler = fpemu_dp_msub;
                        goto dcoptop;
                case nmadd_d_op:
                        if (cpu_has_mac2008_only)
                                handler = ieee754dp_nmadd;
                        else
                                handler = fpemu_dp_nmadd;
                        goto dcoptop;
                case nmsub_d_op:
                        if (cpu_has_mac2008_only)
                                handler = ieee754dp_nmsub;
                        else
                        handler = fpemu_dp_nmsub;
                        goto dcoptop;

                      dcoptop:
                        DPFROMREG(fr, MIPSInst_FR(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        fd = (*handler) (fr, fs, ft);
                        DPTOREG(fd, MIPSInst_FD(ir));
                        goto copcsr;

                default:
                        return SIGILL;
                }
                break;
        }

        case 0x7:
                if (MIPSInst_FUNC(ir) != pfetch_op)
                        return SIGILL;

                /* ignore prefx operation */
                break;

        default:
                return SIGILL;
        }

        return 0;
}



/*
 * Emulate a single COP1 arithmetic instruction.
 */
static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
        mips_instruction ir)
{
        int rfmt;               /* resulting format */
        unsigned int rcsr = 0;  /* resulting csr */
        unsigned int oldrm;
        unsigned int cbit;
        unsigned int cond;
        union {
                union ieee754dp d;
                union ieee754sp s;
                int w;
                s64 l;
        } rv;                   /* resulting value */
        u64 bits;

        MIPS_FPU_EMU_INC_STATS(cp1ops);
        switch (rfmt = (MIPSInst_FFMT(ir) & 0xf)) {
        case s_fmt: {           /* 0 */
                union {
                        union ieee754sp(*b) (union ieee754sp, union ieee754sp);
                        union ieee754sp(*u) (union ieee754sp);
                } handler;
                union ieee754sp fd, fs, ft;

                switch (MIPSInst_FUNC(ir)) {
                        /* binary ops */
                case fadd_op:
                        MIPS_FPU_EMU_INC_STATS(add_s);
                        handler.b = ieee754sp_add;
                        goto scopbop;
                case fsub_op:
                        MIPS_FPU_EMU_INC_STATS(sub_s);
                        handler.b = ieee754sp_sub;
                        goto scopbop;
                case fmul_op:
                        MIPS_FPU_EMU_INC_STATS(mul_s);
                        handler.b = ieee754sp_mul;
                        goto scopbop;
                case fdiv_op:
                        MIPS_FPU_EMU_INC_STATS(div_s);
                        handler.b = ieee754sp_div;
                        goto scopbop;

                        /* unary  ops */
                case fsqrt_op:
                        if (!cpu_has_mips_2_3_4_5_r)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(sqrt_s);
                        handler.u = ieee754sp_sqrt;
                        goto scopuop;

                /*
                 * Note that on some MIPS IV implementations such as the
                 * R5000 and R8000 the FSQRT and FRECIP instructions do not
                 * achieve full IEEE-754 accuracy - however this emulator does.
                 */
                case frsqrt_op:
                        if (!cpu_has_mips_4_5_64_r2_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(rsqrt_s);
                        handler.u = fpemu_sp_rsqrt;
                        goto scopuop;

                case frecip_op:
                        if (!cpu_has_mips_4_5_64_r2_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(recip_s);
                        handler.u = fpemu_sp_recip;
                        goto scopuop;

                case fmovc_op:
                        if (!cpu_has_mips_4_5_r)
                                return SIGILL;

                        cond = fpucondbit[MIPSInst_FT(ir) >> 2];
                        if (((ctx->fcr31 & cond) != 0) !=
                                ((MIPSInst_FT(ir) & 1) != 0))
                                return 0;
                        SPFROMREG(rv.s, MIPSInst_FS(ir));
                        break;

                case fmovz_op:
                        if (!cpu_has_mips_4_5_r)
                                return SIGILL;

                        if (xcp->regs[MIPSInst_FT(ir)] != 0)
                                return 0;
                        SPFROMREG(rv.s, MIPSInst_FS(ir));
                        break;

                case fmovn_op:
                        if (!cpu_has_mips_4_5_r)
                                return SIGILL;

                        if (xcp->regs[MIPSInst_FT(ir)] == 0)
                                return 0;
                        SPFROMREG(rv.s, MIPSInst_FS(ir));
                        break;

                case fseleqz_op:
                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(seleqz_s);
                        SPFROMREG(rv.s, MIPSInst_FT(ir));
                        if (rv.w & 0x1)
                                rv.w = 0;
                        else
                                SPFROMREG(rv.s, MIPSInst_FS(ir));
                        break;

                case fselnez_op:
                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(selnez_s);
                        SPFROMREG(rv.s, MIPSInst_FT(ir));
                        if (rv.w & 0x1)
                                SPFROMREG(rv.s, MIPSInst_FS(ir));
                        else
                                rv.w = 0;
                        break;

                case fmaddf_op: {
                        union ieee754sp ft, fs, fd;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(maddf_s);
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        SPFROMREG(fd, MIPSInst_FD(ir));
                        rv.s = ieee754sp_maddf(fd, fs, ft);
                        goto copcsr;
                }

                case fmsubf_op: {
                        union ieee754sp ft, fs, fd;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(msubf_s);
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        SPFROMREG(fd, MIPSInst_FD(ir));
                        rv.s = ieee754sp_msubf(fd, fs, ft);
                        goto copcsr;
                }

                case frint_op: {
                        union ieee754sp fs;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(rint_s);
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_rint(fs);
                        goto copcsr;
                }

                case fclass_op: {
                        union ieee754sp fs;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(class_s);
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.w = ieee754sp_2008class(fs);
                        rfmt = w_fmt;
                        goto copcsr;
                }

                case fmin_op: {
                        union ieee754sp fs, ft;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(min_s);
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fmin(fs, ft);
                        goto copcsr;
                }

                case fmina_op: {
                        union ieee754sp fs, ft;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(mina_s);
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fmina(fs, ft);
                        goto copcsr;
                }

                case fmax_op: {
                        union ieee754sp fs, ft;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(max_s);
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fmax(fs, ft);
                        goto copcsr;
                }

                case fmaxa_op: {
                        union ieee754sp fs, ft;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(maxa_s);
                        SPFROMREG(ft, MIPSInst_FT(ir));
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fmaxa(fs, ft);
                        goto copcsr;
                }

                case fabs_op:
                        MIPS_FPU_EMU_INC_STATS(abs_s);
                        handler.u = ieee754sp_abs;
                        goto scopuop;

                case fneg_op:
                        MIPS_FPU_EMU_INC_STATS(neg_s);
                        handler.u = ieee754sp_neg;
                        goto scopuop;

                case fmov_op:
                        /* an easy one */
                        MIPS_FPU_EMU_INC_STATS(mov_s);
                        SPFROMREG(rv.s, MIPSInst_FS(ir));
                        goto copcsr;

                        /* binary op on handler */
scopbop:
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        SPFROMREG(ft, MIPSInst_FT(ir));

                        rv.s = (*handler.b) (fs, ft);
                        goto copcsr;
scopuop:
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = (*handler.u) (fs);
                        goto copcsr;
copcsr:
                        if (ieee754_cxtest(IEEE754_INEXACT)) {
                                MIPS_FPU_EMU_INC_STATS(ieee754_inexact);
                                rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
                        }
                        if (ieee754_cxtest(IEEE754_UNDERFLOW)) {
                                MIPS_FPU_EMU_INC_STATS(ieee754_underflow);
                                rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
                        }
                        if (ieee754_cxtest(IEEE754_OVERFLOW)) {
                                MIPS_FPU_EMU_INC_STATS(ieee754_overflow);
                                rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
                        }
                        if (ieee754_cxtest(IEEE754_ZERO_DIVIDE)) {
                                MIPS_FPU_EMU_INC_STATS(ieee754_zerodiv);
                                rcsr |= FPU_CSR_DIV_X | FPU_CSR_DIV_S;
                        }
                        if (ieee754_cxtest(IEEE754_INVALID_OPERATION)) {
                                MIPS_FPU_EMU_INC_STATS(ieee754_invalidop);
                                rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
                        }
                        break;

                        /* unary conv ops */
                case fcvts_op:
                        return SIGILL;  /* not defined */

                case fcvtd_op:
                        MIPS_FPU_EMU_INC_STATS(cvt_d_s);
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fsp(fs);
                        rfmt = d_fmt;
                        goto copcsr;

                case fcvtw_op:
                        MIPS_FPU_EMU_INC_STATS(cvt_w_s);
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.w = ieee754sp_tint(fs);
                        rfmt = w_fmt;
                        goto copcsr;

                case fround_op:
                case ftrunc_op:
                case fceil_op:
                case ffloor_op:
                        if (!cpu_has_mips_2_3_4_5_r)
                                return SIGILL;

                        if (MIPSInst_FUNC(ir) == fceil_op)
                                MIPS_FPU_EMU_INC_STATS(ceil_w_s);
                        if (MIPSInst_FUNC(ir) == ffloor_op)
                                MIPS_FPU_EMU_INC_STATS(floor_w_s);
                        if (MIPSInst_FUNC(ir) == fround_op)
                                MIPS_FPU_EMU_INC_STATS(round_w_s);
                        if (MIPSInst_FUNC(ir) == ftrunc_op)
                                MIPS_FPU_EMU_INC_STATS(trunc_w_s);

                        oldrm = ieee754_csr.rm;
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        ieee754_csr.rm = MIPSInst_FUNC(ir);
                        rv.w = ieee754sp_tint(fs);
                        ieee754_csr.rm = oldrm;
                        rfmt = w_fmt;
                        goto copcsr;

                case fsel_op:
                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(sel_s);
                        SPFROMREG(fd, MIPSInst_FD(ir));
                        if (fd.bits & 0x1)
                                SPFROMREG(rv.s, MIPSInst_FT(ir));
                        else
                                SPFROMREG(rv.s, MIPSInst_FS(ir));
                        break;

                case fcvtl_op:
                        if (!cpu_has_mips_3_4_5_64_r2_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(cvt_l_s);
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.l = ieee754sp_tlong(fs);
                        rfmt = l_fmt;
                        goto copcsr;

                case froundl_op:
                case ftruncl_op:
                case fceill_op:
                case ffloorl_op:
                        if (!cpu_has_mips_3_4_5_64_r2_r6)
                                return SIGILL;

                        if (MIPSInst_FUNC(ir) == fceill_op)
                                MIPS_FPU_EMU_INC_STATS(ceil_l_s);
                        if (MIPSInst_FUNC(ir) == ffloorl_op)
                                MIPS_FPU_EMU_INC_STATS(floor_l_s);
                        if (MIPSInst_FUNC(ir) == froundl_op)
                                MIPS_FPU_EMU_INC_STATS(round_l_s);
                        if (MIPSInst_FUNC(ir) == ftruncl_op)
                                MIPS_FPU_EMU_INC_STATS(trunc_l_s);

                        oldrm = ieee754_csr.rm;
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        ieee754_csr.rm = MIPSInst_FUNC(ir);
                        rv.l = ieee754sp_tlong(fs);
                        ieee754_csr.rm = oldrm;
                        rfmt = l_fmt;
                        goto copcsr;

                default:
                        if (!NO_R6EMU && MIPSInst_FUNC(ir) >= fcmp_op) {
                                unsigned int cmpop;
                                union ieee754sp fs, ft;

                                cmpop = MIPSInst_FUNC(ir) - fcmp_op;
                                SPFROMREG(fs, MIPSInst_FS(ir));
                                SPFROMREG(ft, MIPSInst_FT(ir));
                                rv.w = ieee754sp_cmp(fs, ft,
                                        cmptab[cmpop & 0x7], cmpop & 0x8);
                                rfmt = -1;
                                if ((cmpop & 0x8) && ieee754_cxtest
                                        (IEEE754_INVALID_OPERATION))
                                        rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
                                else
                                        goto copcsr;

                        } else
                                return SIGILL;
                        break;
                }
                break;
        }

        case d_fmt: {
                union ieee754dp fd, fs, ft;
                union {
                        union ieee754dp(*b) (union ieee754dp, union ieee754dp);
                        union ieee754dp(*u) (union ieee754dp);
                } handler;

                switch (MIPSInst_FUNC(ir)) {
                        /* binary ops */
                case fadd_op:
                        MIPS_FPU_EMU_INC_STATS(add_d);
                        handler.b = ieee754dp_add;
                        goto dcopbop;
                case fsub_op:
                        MIPS_FPU_EMU_INC_STATS(sub_d);
                        handler.b = ieee754dp_sub;
                        goto dcopbop;
                case fmul_op:
                        MIPS_FPU_EMU_INC_STATS(mul_d);
                        handler.b = ieee754dp_mul;
                        goto dcopbop;
                case fdiv_op:
                        MIPS_FPU_EMU_INC_STATS(div_d);
                        handler.b = ieee754dp_div;
                        goto dcopbop;

                        /* unary  ops */
                case fsqrt_op:
                        if (!cpu_has_mips_2_3_4_5_r)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(sqrt_d);
                        handler.u = ieee754dp_sqrt;
                        goto dcopuop;
                /*
                 * Note that on some MIPS IV implementations such as the
                 * R5000 and R8000 the FSQRT and FRECIP instructions do not
                 * achieve full IEEE-754 accuracy - however this emulator does.
                 */
                case frsqrt_op:
                        if (!cpu_has_mips_4_5_64_r2_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(rsqrt_d);
                        handler.u = fpemu_dp_rsqrt;
                        goto dcopuop;
                case frecip_op:
                        if (!cpu_has_mips_4_5_64_r2_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(recip_d);
                        handler.u = fpemu_dp_recip;
                        goto dcopuop;
                case fmovc_op:
                        if (!cpu_has_mips_4_5_r)
                                return SIGILL;

                        cond = fpucondbit[MIPSInst_FT(ir) >> 2];
                        if (((ctx->fcr31 & cond) != 0) !=
                                ((MIPSInst_FT(ir) & 1) != 0))
                                return 0;
                        DPFROMREG(rv.d, MIPSInst_FS(ir));
                        break;
                case fmovz_op:
                        if (!cpu_has_mips_4_5_r)
                                return SIGILL;

                        if (xcp->regs[MIPSInst_FT(ir)] != 0)
                                return 0;
                        DPFROMREG(rv.d, MIPSInst_FS(ir));
                        break;
                case fmovn_op:
                        if (!cpu_has_mips_4_5_r)
                                return SIGILL;

                        if (xcp->regs[MIPSInst_FT(ir)] == 0)
                                return 0;
                        DPFROMREG(rv.d, MIPSInst_FS(ir));
                        break;

                case fseleqz_op:
                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(seleqz_d);
                        DPFROMREG(rv.d, MIPSInst_FT(ir));
                        if (rv.l & 0x1)
                                rv.l = 0;
                        else
                                DPFROMREG(rv.d, MIPSInst_FS(ir));
                        break;

                case fselnez_op:
                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(selnez_d);
                        DPFROMREG(rv.d, MIPSInst_FT(ir));
                        if (rv.l & 0x1)
                                DPFROMREG(rv.d, MIPSInst_FS(ir));
                        else
                                rv.l = 0;
                        break;

                case fmaddf_op: {
                        union ieee754dp ft, fs, fd;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(maddf_d);
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        DPFROMREG(fd, MIPSInst_FD(ir));
                        rv.d = ieee754dp_maddf(fd, fs, ft);
                        goto copcsr;
                }

                case fmsubf_op: {
                        union ieee754dp ft, fs, fd;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(msubf_d);
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        DPFROMREG(fd, MIPSInst_FD(ir));
                        rv.d = ieee754dp_msubf(fd, fs, ft);
                        goto copcsr;
                }

                case frint_op: {
                        union ieee754dp fs;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(rint_d);
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_rint(fs);
                        goto copcsr;
                }

                case fclass_op: {
                        union ieee754dp fs;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(class_d);
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.l = ieee754dp_2008class(fs);
                        rfmt = l_fmt;
                        goto copcsr;
                }

                case fmin_op: {
                        union ieee754dp fs, ft;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(min_d);
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fmin(fs, ft);
                        goto copcsr;
                }

                case fmina_op: {
                        union ieee754dp fs, ft;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(mina_d);
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fmina(fs, ft);
                        goto copcsr;
                }

                case fmax_op: {
                        union ieee754dp fs, ft;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(max_d);
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fmax(fs, ft);
                        goto copcsr;
                }

                case fmaxa_op: {
                        union ieee754dp fs, ft;

                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(maxa_d);
                        DPFROMREG(ft, MIPSInst_FT(ir));
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fmaxa(fs, ft);
                        goto copcsr;
                }

                case fabs_op:
                        MIPS_FPU_EMU_INC_STATS(abs_d);
                        handler.u = ieee754dp_abs;
                        goto dcopuop;

                case fneg_op:
                        MIPS_FPU_EMU_INC_STATS(neg_d);
                        handler.u = ieee754dp_neg;
                        goto dcopuop;

                case fmov_op:
                        /* an easy one */
                        MIPS_FPU_EMU_INC_STATS(mov_d);
                        DPFROMREG(rv.d, MIPSInst_FS(ir));
                        goto copcsr;

                        /* binary op on handler */
dcopbop:
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        DPFROMREG(ft, MIPSInst_FT(ir));

                        rv.d = (*handler.b) (fs, ft);
                        goto copcsr;
dcopuop:
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = (*handler.u) (fs);
                        goto copcsr;

                /*
                 * unary conv ops
                 */
                case fcvts_op:
                        MIPS_FPU_EMU_INC_STATS(cvt_s_d);
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fdp(fs);
                        rfmt = s_fmt;
                        goto copcsr;

                case fcvtd_op:
                        return SIGILL;  /* not defined */

                case fcvtw_op:
                        MIPS_FPU_EMU_INC_STATS(cvt_w_d);
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.w = ieee754dp_tint(fs);      /* wrong */
                        rfmt = w_fmt;
                        goto copcsr;

                case fround_op:
                case ftrunc_op:
                case fceil_op:
                case ffloor_op:
                        if (!cpu_has_mips_2_3_4_5_r)
                                return SIGILL;

                        if (MIPSInst_FUNC(ir) == fceil_op)
                                MIPS_FPU_EMU_INC_STATS(ceil_w_d);
                        if (MIPSInst_FUNC(ir) == ffloor_op)
                                MIPS_FPU_EMU_INC_STATS(floor_w_d);
                        if (MIPSInst_FUNC(ir) == fround_op)
                                MIPS_FPU_EMU_INC_STATS(round_w_d);
                        if (MIPSInst_FUNC(ir) == ftrunc_op)
                                MIPS_FPU_EMU_INC_STATS(trunc_w_d);

                        oldrm = ieee754_csr.rm;
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        ieee754_csr.rm = MIPSInst_FUNC(ir);
                        rv.w = ieee754dp_tint(fs);
                        ieee754_csr.rm = oldrm;
                        rfmt = w_fmt;
                        goto copcsr;

                case fsel_op:
                        if (!cpu_has_mips_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(sel_d);
                        DPFROMREG(fd, MIPSInst_FD(ir));
                        if (fd.bits & 0x1)
                                DPFROMREG(rv.d, MIPSInst_FT(ir));
                        else
                                DPFROMREG(rv.d, MIPSInst_FS(ir));
                        break;

                case fcvtl_op:
                        if (!cpu_has_mips_3_4_5_64_r2_r6)
                                return SIGILL;

                        MIPS_FPU_EMU_INC_STATS(cvt_l_d);
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        rv.l = ieee754dp_tlong(fs);
                        rfmt = l_fmt;
                        goto copcsr;

                case froundl_op:
                case ftruncl_op:
                case fceill_op:
                case ffloorl_op:
                        if (!cpu_has_mips_3_4_5_64_r2_r6)
                                return SIGILL;

                        if (MIPSInst_FUNC(ir) == fceill_op)
                                MIPS_FPU_EMU_INC_STATS(ceil_l_d);
                        if (MIPSInst_FUNC(ir) == ffloorl_op)
                                MIPS_FPU_EMU_INC_STATS(floor_l_d);
                        if (MIPSInst_FUNC(ir) == froundl_op)
                                MIPS_FPU_EMU_INC_STATS(round_l_d);
                        if (MIPSInst_FUNC(ir) == ftruncl_op)
                                MIPS_FPU_EMU_INC_STATS(trunc_l_d);

                        oldrm = ieee754_csr.rm;
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        ieee754_csr.rm = MIPSInst_FUNC(ir);
                        rv.l = ieee754dp_tlong(fs);
                        ieee754_csr.rm = oldrm;
                        rfmt = l_fmt;
                        goto copcsr;

                default:
                        if (!NO_R6EMU && MIPSInst_FUNC(ir) >= fcmp_op) {
                                unsigned int cmpop;
                                union ieee754dp fs, ft;

                                cmpop = MIPSInst_FUNC(ir) - fcmp_op;
                                DPFROMREG(fs, MIPSInst_FS(ir));
                                DPFROMREG(ft, MIPSInst_FT(ir));
                                rv.w = ieee754dp_cmp(fs, ft,
                                        cmptab[cmpop & 0x7], cmpop & 0x8);
                                rfmt = -1;
                                if ((cmpop & 0x8)
                                        &&
                                        ieee754_cxtest
                                        (IEEE754_INVALID_OPERATION))
                                        rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
                                else
                                        goto copcsr;

                        }
                        else {
                                return SIGILL;
                        }
                        break;
                }
                break;
        }

        case w_fmt: {
                union ieee754dp fs;

                switch (MIPSInst_FUNC(ir)) {
                case fcvts_op:
                        /* convert word to single precision real */
                        MIPS_FPU_EMU_INC_STATS(cvt_s_w);
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.s = ieee754sp_fint(fs.bits);
                        rfmt = s_fmt;
                        goto copcsr;
                case fcvtd_op:
                        /* convert word to double precision real */
                        MIPS_FPU_EMU_INC_STATS(cvt_d_w);
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        rv.d = ieee754dp_fint(fs.bits);
                        rfmt = d_fmt;
                        goto copcsr;
                default: {
                        /* Emulating the new CMP.condn.fmt R6 instruction */
#define CMPOP_MASK      0x7
#define SIGN_BIT        (0x1 << 3)
#define PREDICATE_BIT   (0x1 << 4)

                        int cmpop = MIPSInst_FUNC(ir) & CMPOP_MASK;
                        int sig = MIPSInst_FUNC(ir) & SIGN_BIT;
                        union ieee754sp fs, ft;

                        /* This is an R6 only instruction */
                        if (!cpu_has_mips_r6 ||
                            (MIPSInst_FUNC(ir) & 0x20))
                                return SIGILL;

                        if (!sig) {
                                if (!(MIPSInst_FUNC(ir) & PREDICATE_BIT)) {
                                        switch (cmpop) {
                                        case 0:
                                        MIPS_FPU_EMU_INC_STATS(cmp_af_s);
                                        break;
                                        case 1:
                                        MIPS_FPU_EMU_INC_STATS(cmp_un_s);
                                        break;
                                        case 2:
                                        MIPS_FPU_EMU_INC_STATS(cmp_eq_s);
                                        break;
                                        case 3:
                                        MIPS_FPU_EMU_INC_STATS(cmp_ueq_s);
                                        break;
                                        case 4:
                                        MIPS_FPU_EMU_INC_STATS(cmp_lt_s);
                                        break;
                                        case 5:
                                        MIPS_FPU_EMU_INC_STATS(cmp_ult_s);
                                        break;
                                        case 6:
                                        MIPS_FPU_EMU_INC_STATS(cmp_le_s);
                                        break;
                                        case 7:
                                        MIPS_FPU_EMU_INC_STATS(cmp_ule_s);
                                        break;
                                        }
                                } else {
                                        switch (cmpop) {
                                        case 1:
                                        MIPS_FPU_EMU_INC_STATS(cmp_or_s);
                                        break;
                                        case 2:
                                        MIPS_FPU_EMU_INC_STATS(cmp_une_s);
                                        break;
                                        case 3:
                                        MIPS_FPU_EMU_INC_STATS(cmp_ne_s);
                                        break;
                                        }
                                }
                        } else {
                                if (!(MIPSInst_FUNC(ir) & PREDICATE_BIT)) {
                                        switch (cmpop) {
                                        case 0:
                                        MIPS_FPU_EMU_INC_STATS(cmp_saf_s);
                                        break;
                                        case 1:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sun_s);
                                        break;
                                        case 2:
                                        MIPS_FPU_EMU_INC_STATS(cmp_seq_s);
                                        break;
                                        case 3:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sueq_s);
                                        break;
                                        case 4:
                                        MIPS_FPU_EMU_INC_STATS(cmp_slt_s);
                                        break;
                                        case 5:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sult_s);
                                        break;
                                        case 6:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sle_s);
                                        break;
                                        case 7:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sule_s);
                                        break;
                                        }
                                } else {
                                        switch (cmpop) {
                                        case 1:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sor_s);
                                        break;
                                        case 2:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sune_s);
                                        break;
                                        case 3:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sne_s);
                                        break;
                                        }
                                }
                        }

                        /* fmt is w_fmt for single precision so fix it */
                        rfmt = s_fmt;
                        /* default to false */
                        rv.w = 0;

                        /* CMP.condn.S */
                        SPFROMREG(fs, MIPSInst_FS(ir));
                        SPFROMREG(ft, MIPSInst_FT(ir));

                        /* positive predicates */
                        if (!(MIPSInst_FUNC(ir) & PREDICATE_BIT)) {
                                if (ieee754sp_cmp(fs, ft, cmptab[cmpop],
                                                  sig))
                                    rv.w = -1; /* true, all 1s */
                                if ((sig) &&
                                    ieee754_cxtest(IEEE754_INVALID_OPERATION))
                                        rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
                                else
                                        goto copcsr;
                        } else {
                                /* negative predicates */
                                switch (cmpop) {
                                case 1:
                                case 2:
                                case 3:
                                        if (ieee754sp_cmp(fs, ft,
                                                          negative_cmptab[cmpop],
                                                          sig))
                                                rv.w = -1; /* true, all 1s */
                                        if (sig &&
                                            ieee754_cxtest(IEEE754_INVALID_OPERATION))
                                                rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
                                        else
                                                goto copcsr;
                                        break;
                                default:
                                        /* Reserved R6 ops */
                                        return SIGILL;
                                }
                        }
                        break;
                        }
                }
                break;
        }

        case l_fmt:

                if (!cpu_has_mips_3_4_5_64_r2_r6)
                        return SIGILL;

                DIFROMREG(bits, MIPSInst_FS(ir));

                switch (MIPSInst_FUNC(ir)) {
                case fcvts_op:
                        /* convert long to single precision real */
                        MIPS_FPU_EMU_INC_STATS(cvt_s_l);
                        rv.s = ieee754sp_flong(bits);
                        rfmt = s_fmt;
                        goto copcsr;
                case fcvtd_op:
                        /* convert long to double precision real */
                        MIPS_FPU_EMU_INC_STATS(cvt_d_l);
                        rv.d = ieee754dp_flong(bits);
                        rfmt = d_fmt;
                        goto copcsr;
                default: {
                        /* Emulating the new CMP.condn.fmt R6 instruction */
                        int cmpop = MIPSInst_FUNC(ir) & CMPOP_MASK;
                        int sig = MIPSInst_FUNC(ir) & SIGN_BIT;
                        union ieee754dp fs, ft;

                        if (!cpu_has_mips_r6 ||
                            (MIPSInst_FUNC(ir) & 0x20))
                                return SIGILL;

                        if (!sig) {
                                if (!(MIPSInst_FUNC(ir) & PREDICATE_BIT)) {
                                        switch (cmpop) {
                                        case 0:
                                        MIPS_FPU_EMU_INC_STATS(cmp_af_d);
                                        break;
                                        case 1:
                                        MIPS_FPU_EMU_INC_STATS(cmp_un_d);
                                        break;
                                        case 2:
                                        MIPS_FPU_EMU_INC_STATS(cmp_eq_d);
                                        break;
                                        case 3:
                                        MIPS_FPU_EMU_INC_STATS(cmp_ueq_d);
                                        break;
                                        case 4:
                                        MIPS_FPU_EMU_INC_STATS(cmp_lt_d);
                                        break;
                                        case 5:
                                        MIPS_FPU_EMU_INC_STATS(cmp_ult_d);
                                        break;
                                        case 6:
                                        MIPS_FPU_EMU_INC_STATS(cmp_le_d);
                                        break;
                                        case 7:
                                        MIPS_FPU_EMU_INC_STATS(cmp_ule_d);
                                        break;
                                        }
                                } else {
                                        switch (cmpop) {
                                        case 1:
                                        MIPS_FPU_EMU_INC_STATS(cmp_or_d);
                                        break;
                                        case 2:
                                        MIPS_FPU_EMU_INC_STATS(cmp_une_d);
                                        break;
                                        case 3:
                                        MIPS_FPU_EMU_INC_STATS(cmp_ne_d);
                                        break;
                                        }
                                }
                        } else {
                                if (!(MIPSInst_FUNC(ir) & PREDICATE_BIT)) {
                                        switch (cmpop) {
                                        case 0:
                                        MIPS_FPU_EMU_INC_STATS(cmp_saf_d);
                                        break;
                                        case 1:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sun_d);
                                        break;
                                        case 2:
                                        MIPS_FPU_EMU_INC_STATS(cmp_seq_d);
                                        break;
                                        case 3:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sueq_d);
                                        break;
                                        case 4:
                                        MIPS_FPU_EMU_INC_STATS(cmp_slt_d);
                                        break;
                                        case 5:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sult_d);
                                        break;
                                        case 6:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sle_d);
                                        break;
                                        case 7:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sule_d);
                                        break;
                                        }
                                } else {
                                        switch (cmpop) {
                                        case 1:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sor_d);
                                        break;
                                        case 2:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sune_d);
                                        break;
                                        case 3:
                                        MIPS_FPU_EMU_INC_STATS(cmp_sne_d);
                                        break;
                                        }
                                }
                        }

                        /* fmt is l_fmt for double precision so fix it */
                        rfmt = d_fmt;
                        /* default to false */
                        rv.l = 0;

                        /* CMP.condn.D */
                        DPFROMREG(fs, MIPSInst_FS(ir));
                        DPFROMREG(ft, MIPSInst_FT(ir));

                        /* positive predicates */
                        if (!(MIPSInst_FUNC(ir) & PREDICATE_BIT)) {
                                if (ieee754dp_cmp(fs, ft,
                                                  cmptab[cmpop], sig))
                                    rv.l = -1LL; /* true, all 1s */
                                if (sig &&
                                    ieee754_cxtest(IEEE754_INVALID_OPERATION))
                                        rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
                                else
                                        goto copcsr;
                        } else {
                                /* negative predicates */
                                switch (cmpop) {
                                case 1:
                                case 2:
                                case 3:
                                        if (ieee754dp_cmp(fs, ft,
                                                          negative_cmptab[cmpop],
                                                          sig))
                                                rv.l = -1LL; /* true, all 1s */
                                        if (sig &&
                                            ieee754_cxtest(IEEE754_INVALID_OPERATION))
                                                rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
                                        else
                                                goto copcsr;
                                        break;
                                default:
                                        /* Reserved R6 ops */
                                        return SIGILL;
                                }
                        }
                        break;
                        }
                }
                break;

        default:
                return SIGILL;
        }

        /*
         * Update the fpu CSR register for this operation.
         * If an exception is required, generate a tidy SIGFPE exception,
         * without updating the result register.
         * Note: cause exception bits do not accumulate, they are rewritten
         * for each op; only the flag/sticky bits accumulate.
         */
        ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
        if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
                /*printk ("SIGFPE: FPU csr = %08x\n",ctx->fcr31); */
                return SIGFPE;
        }

        /*
         * Now we can safely write the result back to the register file.
         */
        switch (rfmt) {
        case -1:

                if (cpu_has_mips_4_5_r)
                        cbit = fpucondbit[MIPSInst_FD(ir) >> 2];
                else
                        cbit = FPU_CSR_COND;
                if (rv.w)
                        ctx->fcr31 |= cbit;
                else
                        ctx->fcr31 &= ~cbit;
                break;

        case d_fmt:
                DPTOREG(rv.d, MIPSInst_FD(ir));
                break;
        case s_fmt:
                SPTOREG(rv.s, MIPSInst_FD(ir));
                break;
        case w_fmt:
                SITOREG(rv.w, MIPSInst_FD(ir));
                break;
        case l_fmt:
                if (!cpu_has_mips_3_4_5_64_r2_r6)
                        return SIGILL;

                DITOREG(rv.l, MIPSInst_FD(ir));
                break;
        default:
                return SIGILL;
        }

        return 0;
}

/*
 * Emulate FPU instructions.
 *
 * If we use FPU hardware, then we have been typically called to handle
 * an unimplemented operation, such as where an operand is a NaN or
 * denormalized.  In that case exit the emulation loop after a single
 * iteration so as to let hardware execute any subsequent instructions.
 *
 * If we have no FPU hardware or it has been disabled, then continue
 * emulating floating-point instructions until one of these conditions
 * has occurred:
 *
 * - a non-FPU instruction has been encountered,
 *
 * - an attempt to emulate has ended with a signal,
 *
 * - the ISA mode has been switched.
 *
 * We need to terminate the emulation loop if we got switched to the
 * MIPS16 mode, whether supported or not, so that we do not attempt
 * to emulate a MIPS16 instruction as a regular MIPS FPU instruction.
 * Similarly if we got switched to the microMIPS mode and only the
 * regular MIPS mode is supported, so that we do not attempt to emulate
 * a microMIPS instruction as a regular MIPS FPU instruction.  Or if
 * we got switched to the regular MIPS mode and only the microMIPS mode
 * is supported, so that we do not attempt to emulate a regular MIPS
 * instruction that should cause an Address Error exception instead.
 * For simplicity we always terminate upon an ISA mode switch.
 */
int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
        int has_fpu, void __user **fault_addr)
{
        unsigned long oldepc, prevepc;
        struct mm_decoded_insn dec_insn;
        u16 instr[4];
        u16 *instr_ptr;
        int sig = 0;

        /*
         * Initialize context if it hasn't been used already, otherwise ensure
         * it has been saved to struct thread_struct.
         */
        if (!init_fp_ctx(current))
                lose_fpu(1);

        oldepc = xcp->cp0_epc;
        do {
                prevepc = xcp->cp0_epc;

                if (get_isa16_mode(prevepc) && cpu_has_mmips) {
                        /*
                         * Get next 2 microMIPS instructions and convert them
                         * into 32-bit instructions.
                         */
                        if ((get_user(instr[0], (u16 __user *)msk_isa16_mode(xcp->cp0_epc))) ||
                            (get_user(instr[1], (u16 __user *)msk_isa16_mode(xcp->cp0_epc + 2))) ||
                            (get_user(instr[2], (u16 __user *)msk_isa16_mode(xcp->cp0_epc + 4))) ||
                            (get_user(instr[3], (u16 __user *)msk_isa16_mode(xcp->cp0_epc + 6)))) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                return SIGBUS;
                        }
                        instr_ptr = instr;

                        /* Get first instruction. */
                        if (mm_insn_16bit(*instr_ptr)) {
                                /* Duplicate the half-word. */
                                dec_insn.insn = (*instr_ptr << 16) |
                                        (*instr_ptr);
                                /* 16-bit instruction. */
                                dec_insn.pc_inc = 2;
                                instr_ptr += 1;
                        } else {
                                dec_insn.insn = (*instr_ptr << 16) |
                                        *(instr_ptr+1);
                                /* 32-bit instruction. */
                                dec_insn.pc_inc = 4;
                                instr_ptr += 2;
                        }
                        /* Get second instruction. */
                        if (mm_insn_16bit(*instr_ptr)) {
                                /* Duplicate the half-word. */
                                dec_insn.next_insn = (*instr_ptr << 16) |
                                        (*instr_ptr);
                                /* 16-bit instruction. */
                                dec_insn.next_pc_inc = 2;
                        } else {
                                dec_insn.next_insn = (*instr_ptr << 16) |
                                        *(instr_ptr+1);
                                /* 32-bit instruction. */
                                dec_insn.next_pc_inc = 4;
                        }
                        dec_insn.micro_mips_mode = 1;
                } else {
                        if ((get_user(dec_insn.insn,
                            (mips_instruction __user *) xcp->cp0_epc)) ||
                            (get_user(dec_insn.next_insn,
                            (mips_instruction __user *)(xcp->cp0_epc+4)))) {
                                MIPS_FPU_EMU_INC_STATS(errors);
                                return SIGBUS;
                        }
                        dec_insn.pc_inc = 4;
                        dec_insn.next_pc_inc = 4;
                        dec_insn.micro_mips_mode = 0;
                }

                if ((dec_insn.insn == 0) ||
                   ((dec_insn.pc_inc == 2) &&
                   ((dec_insn.insn & 0xffff) == MM_NOP16)))
                        xcp->cp0_epc += dec_insn.pc_inc;        /* Skip NOPs */
                else {
                        /*
                         * The 'ieee754_csr' is an alias of ctx->fcr31.
                         * No need to copy ctx->fcr31 to ieee754_csr.
                         */
                        sig = cop1Emulate(xcp, ctx, dec_insn, fault_addr);
                }

                if (has_fpu)
                        break;
                if (sig)
                        break;
                /*
                 * We have to check for the ISA bit explicitly here,
                 * because `get_isa16_mode' may return 0 if support
                 * for code compression has been globally disabled,
                 * or otherwise we may produce the wrong signal or
                 * even proceed successfully where we must not.
                 */
                if ((xcp->cp0_epc ^ prevepc) & 0x1)
                        break;

                cond_resched();
        } while (xcp->cp0_epc > prevepc);

        /* SIGILL indicates a non-fpu instruction */
        if (sig == SIGILL && xcp->cp0_epc != oldepc)
                /* but if EPC has advanced, then ignore it */
                sig = 0;

        return sig;
}