xref: /netbsd-src/sys/external/bsd/compiler_rt/dist/lib/builtins/arm/divsi3.S (revision f6e43b3179e19718c2af5950ddbd1384060c23e7)
1/*===-- divsi3.S - 32-bit signed integer divide ---------------------------===//
2 *
3 *                     The LLVM Compiler Infrastructure
4 *
5 * This file is dual licensed under the MIT and the University of Illinois Open
6 * Source Licenses. See LICENSE.TXT for details.
7 *
8 *===----------------------------------------------------------------------===//
9 *
10 * This file implements the __divsi3 (32-bit signed integer divide) function
11 * for the ARM architecture as a wrapper around the unsigned routine.
12 *
13 *===----------------------------------------------------------------------===*/
14
15#include "../assembly.h"
16
17#define ESTABLISH_FRAME \
18    push   {r4, lr}
19#define CLEAR_FRAME_AND_RETURN \
20    pop    {r4, pc}
21
22	.syntax unified
23	.text
24#if __ARM_ARCH_ISA_THUMB == 2
25	.thumb
26#endif
27
28	.p2align 3
29// Ok, APCS and AAPCS agree on 32 bit args, so it's safe to use the same routine.
30DEFINE_AEABI_FUNCTION_ALIAS(__aeabi_idiv, __divsi3)
31
32@ int __divsi3(int divident, int divisor)
33@   Calculate and return the quotient of the (signed) division.
34
35#if __ARM_ARCH_ISA_THUMB == 2
36DEFINE_COMPILERRT_THUMB_FUNCTION(__divsi3)
37#else
38DEFINE_COMPILERRT_FUNCTION(__divsi3)
39#endif
40#if __ARM_ARCH_EXT_IDIV__
41   tst     r1,r1
42   beq     LOCAL_LABEL(divzero)
43   sdiv    r0, r0, r1
44   bx      lr
45LOCAL_LABEL(divzero):
46   mov     r0,#0
47   bx      lr
48#else
49ESTABLISH_FRAME
50//  Set aside the sign of the quotient.
51    eor     r4,     r0, r1
52//  Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
53    eor     r2,     r0, r0, asr #31
54    eor     r3,     r1, r1, asr #31
55    sub     r0,     r2, r0, asr #31
56    sub     r1,     r3, r1, asr #31
57//  abs(a) / abs(b)
58    bl      SYMBOL_NAME(__udivsi3)
59//  Apply sign of quotient to result and return.
60    eor     r0,     r0, r4, asr #31
61    sub     r0,     r0, r4, asr #31
62    CLEAR_FRAME_AND_RETURN
63#endif
64END_COMPILERRT_FUNCTION(__divsi3)
65