1//===-- divsi3.S - 32-bit signed integer divide ---------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the __divsi3 (32-bit signed integer divide) function
10// for the ARM architecture as a wrapper around the unsigned routine.
11//
12//===----------------------------------------------------------------------===//
13
14#include "../assembly.h"
15
16#define ESTABLISH_FRAME \
17    push   {r4, r7, lr}    ;\
18    add     r7,     sp, #4
19#define CLEAR_FRAME_AND_RETURN \
20    pop    {r4, r7, pc}
21
22   .syntax unified
23   .text
24   DEFINE_CODE_STATE
25
26	.p2align 3
27// Ok, APCS and AAPCS agree on 32 bit args, so it's safe to use the same routine.
28DEFINE_AEABI_FUNCTION_ALIAS(__aeabi_idiv, __divsi3)
29
30@ int __divsi3(int divident, int divisor)
31@   Calculate and return the quotient of the (signed) division.
32
33DEFINE_COMPILERRT_FUNCTION(__divsi3)
34#if __ARM_ARCH_EXT_IDIV__
35   tst     r1,r1
36   beq     LOCAL_LABEL(divzero)
37   sdiv    r0, r0, r1
38   bx      lr
39LOCAL_LABEL(divzero):
40   // Use movs for compatibility with v8-m.base.
41   movs    r0,#0
42   bx      lr
43#else
44ESTABLISH_FRAME
45//  Set aside the sign of the quotient.
46#  if defined(USE_THUMB_1)
47    movs    r4,     r0
48    eors    r4,     r1
49#  else
50    eor     r4,     r0, r1
51#  endif
52//  Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
53#  if defined(USE_THUMB_1)
54    asrs    r2,     r0, #31
55    asrs    r3,     r1, #31
56    eors    r0,     r2
57    eors    r1,     r3
58    subs    r0,     r0, r2
59    subs    r1,     r1, r3
60#  else
61    eor     r2,     r0, r0, asr #31
62    eor     r3,     r1, r1, asr #31
63    sub     r0,     r2, r0, asr #31
64    sub     r1,     r3, r1, asr #31
65#  endif
66//  abs(a) / abs(b)
67    bl      SYMBOL_NAME(__udivsi3)
68//  Apply sign of quotient to result and return.
69#  if defined(USE_THUMB_1)
70    asrs    r4,     #31
71    eors    r0,     r4
72    subs    r0,     r0, r4
73#  else
74    eor     r0,     r0, r4, asr #31
75    sub     r0,     r0, r4, asr #31
76#  endif
77    CLEAR_FRAME_AND_RETURN
78#endif
79END_COMPILERRT_FUNCTION(__divsi3)
80
81NO_EXEC_STACK_DIRECTIVE
82
83