root/arch/arm/vfp/vfphw.S
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *  linux/arch/arm/vfp/vfphw.S
 *
 *  Copyright (C) 2004 ARM Limited.
 *  Written by Deep Blue Solutions Limited.
 */
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/thread_info.h>
#include <asm/vfpmacros.h>
#include <linux/kern_levels.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>

        .macro  DBGSTR1, str, arg
#ifdef DEBUG
        stmfd   sp!, {r0-r3, ip, lr}
        mov     r1, \arg
        ldr     r0, =1f
        bl      _printk
        ldmfd   sp!, {r0-r3, ip, lr}

        .pushsection .rodata, "a"
1:      .ascii  KERN_DEBUG "VFP: \str\n"
        .byte   0
        .previous
#endif
        .endm

ENTRY(vfp_load_state)
        @ Load the current VFP state
        @ r0 - load location
        @ returns FPEXC
        DBGSTR1 "load VFP state %p", r0
                                        @ Load the saved state back into the VFP
        VFPFLDMIA r0, r1                @ reload the working registers while
                                        @ FPEXC is in a safe state
        ldmia   r0, {r0-r3}             @ load FPEXC, FPSCR, FPINST, FPINST2
        tst     r0, #FPEXC_EX           @ is there additional state to restore?
        beq     1f
        VFPFMXR FPINST, r2              @ restore FPINST (only if FPEXC.EX is set)
        tst     r0, #FPEXC_FP2V         @ is there an FPINST2 to write?
        beq     1f
        VFPFMXR FPINST2, r3             @ FPINST2 if needed (and present)
1:
        VFPFMXR FPSCR, r1               @ restore status
        ret     lr
ENDPROC(vfp_load_state)

ENTRY(vfp_save_state)
        @ Save the current VFP state
        @ r0 - save location
        @ r1 - FPEXC
        DBGSTR1 "save VFP state %p", r0
        VFPFSTMIA r0, r2                @ save the working registers
        VFPFMRX r2, FPSCR               @ current status
        tst     r1, #FPEXC_EX           @ is there additional state to save?
        beq     1f
        VFPFMRX r3, FPINST              @ FPINST (only if FPEXC.EX is set)
        tst     r1, #FPEXC_FP2V         @ is there an FPINST2 to read?
        beq     1f
        VFPFMRX r12, FPINST2            @ FPINST2 if needed (and present)
1:
        stmia   r0, {r1, r2, r3, r12}   @ save FPEXC, FPSCR, FPINST, FPINST2
        ret     lr
ENDPROC(vfp_save_state)

        .macro  tbl_branch, base, tmp, shift
#ifdef CONFIG_THUMB2_KERNEL
        adr     \tmp, 1f
        add     \tmp, \tmp, \base, lsl \shift
        ret     \tmp
#else
        add     pc, pc, \base, lsl \shift
        mov     r0, r0
#endif
1:
        .endm

ENTRY(vfp_get_float)
        tbl_branch r0, r3, #3
        .fpu    vfpv2
        .irp    dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
1:      vmov    r0, s\dr
        ret     lr
        .org    1b + 8
        .endr
        .irp    dr,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
1:      vmov    r0, s\dr
        ret     lr
        .org    1b + 8
        .endr
ENDPROC(vfp_get_float)

ENTRY(vfp_put_float)
        tbl_branch r1, r3, #3
        .fpu    vfpv2
        .irp    dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
1:      vmov    s\dr, r0
        ret     lr
        .org    1b + 8
        .endr
        .irp    dr,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
1:      vmov    s\dr, r0
        ret     lr
        .org    1b + 8
        .endr
ENDPROC(vfp_put_float)

ENTRY(vfp_get_double)
        tbl_branch r0, r3, #3
        .fpu    vfpv2
        .irp    dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
1:      vmov    r0, r1, d\dr
        ret     lr
        .org    1b + 8
        .endr
#ifdef CONFIG_VFPv3
        @ d16 - d31 registers
        .fpu    vfpv3
        .irp    dr,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
1:      vmov    r0, r1, d\dr
        ret     lr
        .org    1b + 8
        .endr
#endif

        @ virtual register 16 (or 32 if VFPv3) for compare with zero
        mov     r0, #0
        mov     r1, #0
        ret     lr
ENDPROC(vfp_get_double)

ENTRY(vfp_put_double)
        tbl_branch r2, r3, #3
        .fpu    vfpv2
        .irp    dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
1:      vmov    d\dr, r0, r1
        ret     lr
        .org    1b + 8
        .endr
#ifdef CONFIG_VFPv3
        .fpu    vfpv3
        @ d16 - d31 registers
        .irp    dr,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
1:      vmov    d\dr, r0, r1
        ret     lr
        .org    1b + 8
        .endr
#endif
ENDPROC(vfp_put_double)