/*-
 * Copyright (c) 2012 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matt Thomas of 3am Software Foundry.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <machine/asm.h>

RCSID("$NetBSD: __aeabi_ldivmod.S,v 1.13 2014/05/06 16:02:11 joerg Exp $")

#ifdef __ARMEB__
#define ALO     r1      /* incoming numerator, outgoing quotient */
#define AHI     r0      /* incoming numerator, outgoing quotient */
#define BLO     r3      /* incoming denominator, outgoing remainder */
#define BHI     r2      /* incoming denominator, outgoing remainder */
#else
#define ALO     r0      /* incoming numerator, outgoing quotient */
#define AHI     r1      /* incoming numerator, outgoing quotient */
#define BLO     r2      /* incoming denominator, outgoing remainder */
#define BHI     r3      /* incoming denominator, outgoing remainder */
#endif

ENTRY(__aeabi_ldivmod)
#ifdef __ARM_EABI__
# if !defined(__ARM_DWARF_EH__)
        .fnstart
# endif
        .cfi_startproc
#endif
#if !defined(_KERNEL) && !defined(_STANDALONE)
#if !defined(__thumb__)
        orrs    ip, BLO, BHI
        beq     .Ldivbyzero
#elif defined(_ARM_ARCH_T2)
        cbnz    BLO, 1f
        cbz     BHI, .Ldivbyzero
#else
        cmp     BLO, #0
        bne     1f
        cmp     BHI, #0
        beq     .Ldivbyzero
#endif
1:
#endif

        push    {r4-r6, lr}
#ifdef __ARM_EABI__
        .cfi_def_cfa_offset 16
        .cfi_offset 14, -4
        .cfi_offset 6, -8
        .cfi_offset 5, -12
        .cfi_offset 4, -16
#endif
#define NEG     r5
        movs    NEG, #0

        cmp     BHI, #0
        bge     2f
        movs    NEG, #1         /* flip quotient sign */
        bl      .Lnegate_b
        bcs     .Lmaxdenom

2:
        cmp     AHI, #0
#ifdef __thumb__
        bge     3f
        movs    r4, #3
        eors    NEG, NEG, r4    /* flip quotient sign, flip remainder sign */
        bl      .Lnegate_a
3:
#else
        eorlt   NEG, NEG, #3    /* flip quotient sign, flip remainder sign */
        bllt    .Lnegate_a
#endif

        /*
         * Arguments are setup, allocate some stack for the remainder
         * and call __qdivrem for the heavy lifting.
         */
#ifdef __ARM_EABI__
        .cfi_def_cfa_offset 32
#endif
        sub     sp, sp, #16
#if !defined(__thumb__) || defined(_ARM_ARCH_T2)
        adds    r4, sp, #8
#else
        mov     r4, sp
        adds    r4, r4, #8
#endif
        str     r4, [sp]
        bl      PLT_SYM(__qdivrem)
        add     sp, sp, #8
#ifdef __ARM_EABI__
        .cfi_def_cfa_offset 24
        .cfi_offset 3, -20
        .cfi_offset 2, -24
#endif

        /*
         * The quotient is already in the right place and neither value
         * needs its sign flipped.
         */
#if defined(__thumb__) && defined(_ARM_ARCH_T2)
        cbz     NEG, .Lnegate_neither
#else
        cmp     NEG, #0         /* any signs to flip? */
        beq     .Lnegate_neither
#endif

        cmp     NEG, #2         /* does remainder need to be negative? */
        beq     .Lnegate_b_only /* 2 means b only */
        bgt     .Lnegate_both   /* 3 means both */
.Lnegate_a_only:
        bl      .Lnegate_a      /* 1 means a only */
.Lnegate_neither:
        pop     {r2-r6, pc}     /* grab b from stack */
.Lnegate_both:
        bl      .Lnegate_a
.Lnegate_b_only:
        pop     {r2-r3}         /* get remainder */
#ifdef __ARM_EABI__
        .cfi_def_cfa_offset 16
#endif
        bl      .Lnegate_b      /* negate it */
        pop     {r4-r6, pc}

        .align  0
.Lnegate_a:
#ifdef __thumb__
        movs    r4, AHI
        movs    AHI, #0
        negs    ALO, ALO
        sbcs    AHI, AHI, r4
#else
        negs    ALO, ALO
        rsc     AHI, AHI, #0
#endif
        RET

        .align  0
.Lnegate_b:
#ifdef __thumb__
        movs    r4, BHI
        movs    BHI, #0
        negs    BLO, BLO
        sbcs    BHI, BHI, r4
#else
        negs    BLO, BLO
        rsc     BHI, BHI, #0
#endif
        RET

        .align  0
.Lmaxdenom:
        /*
         * We had a carry so the denominator must have INT64_MIN
         * Also BLO and BHI never changed values so we can use
         * them to see if the numerator has the same value.  We
         * don't have to worry about sign.
         */
        cmp     BHI, AHI
#ifdef __thumb__
        bne     1f
        cmp     BLO, ALO
#else
        cmpeq   BLO, ALO
#endif
        bne     1f

        /*
         * They were equal, so we return a quotient of 1 and remainder of 0.
         */
        movs    ALO, #1
        movs    AHI, #0
        movs    BLO, #0
        movs    BHI, #0
        pop     {r4-r6, pc}

        /*
         * Our remainder must be the numerator and our quotient is 0.
         */
        .align  0
1:      movs    BLO, ALO
        movs    BHI, AHI
        movs    ALO, #0
        movs    AHI, #0
        pop     {r4-r6, pc}

#if !defined(_KERNEL) && !defined(_STANDALONE)
        .align  0
.Ldivbyzero:
        push    {r0-r1,r4,lr}   
#ifdef __ARM_EABI__
# if !defined(__ARM_DWARF_EH__)
        .save   {r0-r1,r4,lr}   
# endif
        .cfi_def_cfa_offset 16
        .cfi_offset 14, -4
        .cfi_offset  4, -8
#endif
        cmp     AHI, #0
#if !defined(__thumb__) || defined(_ARM_ARCH_T2)
#ifdef __thumb__
        ittee   ge
#endif
        mvnge   ALO, #0
        mvnge   AHI, #0x80000000
        movlt   ALO, #0
        movlt   AHI, #0x80000000
#else
        blt     1f
        movs    ALO, #0
        mvns    ALO, ALO
        mov     AHI, ALO
        lsrs    AHI, AHI, #1
        b       2f
1:
        movs    ALO, #0
        movs    AHI, #1
        lsls    AHI, AHI, #31
2:
#endif /* __thumb__ && !_ARM_ARCH_T2 */
        bl      PLT_SYM(__aeabi_ldiv0)
        pop     {r2-r4, pc}
#endif  /* !_KERNEL && !_STANDALONE */
#ifdef __ARM_EABI__
        .cfi_endproc
# if !defined(__ARM_DWARF_EH__)
        .fnend
# endif
#endif
END(__aeabi_ldivmod)