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   mov     r0,#0
41   bx      lr
42#else
43ESTABLISH_FRAME
44//  Set aside the sign of the quotient.
45#  if defined(USE_THUMB_1)
46    movs    r4,     r0
47    eors    r4,     r1
48#  else
49    eor     r4,     r0, r1
50#  endif
51//  Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
52#  if defined(USE_THUMB_1)
53    asrs    r2,     r0, #31
54    asrs    r3,     r1, #31
55    eors    r0,     r2
56    eors    r1,     r3
57    subs    r0,     r0, r2
58    subs    r1,     r1, r3
59#  else
60    eor     r2,     r0, r0, asr #31
61    eor     r3,     r1, r1, asr #31
62    sub     r0,     r2, r0, asr #31
63    sub     r1,     r3, r1, asr #31
64#  endif
65//  abs(a) / abs(b)
66    bl      SYMBOL_NAME(__udivsi3)
67//  Apply sign of quotient to result and return.
68#  if defined(USE_THUMB_1)
69    asrs    r4,     #31
70    eors    r0,     r4
71    subs    r0,     r0, r4
72#  else
73    eor     r0,     r0, r4, asr #31
74    sub     r0,     r0, r4, asr #31
75#  endif
76    CLEAR_FRAME_AND_RETURN
77#endif
78END_COMPILERRT_FUNCTION(__divsi3)
79
80NO_EXEC_STACK_DIRECTIVE
81
82