1//===-- modsi3.S - 32-bit signed integer modulus --------------------------===//
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 __modsi3 (32-bit signed integer modulus) 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@ int __modsi3(int divident, int divisor)
27@   Calculate and return the remainder of the (signed) division.
28
29	.p2align 3
30DEFINE_COMPILERRT_FUNCTION(__modsi3)
31#if __ARM_ARCH_EXT_IDIV__
32	tst     r1, r1
33	beq     LOCAL_LABEL(divzero)
34	sdiv	r2, r0, r1
35	mls 	r0, r2, r1, r0
36	bx      lr
37LOCAL_LABEL(divzero):
38	mov     r0, #0
39	bx      lr
40#else
41    ESTABLISH_FRAME
42    //  Set aside the sign of the dividend.
43    mov     r4,     r0
44    //  Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
45    eor     r2,     r0, r0, asr #31
46    eor     r3,     r1, r1, asr #31
47    sub     r0,     r2, r0, asr #31
48    sub     r1,     r3, r1, asr #31
49    //  abs(a) % abs(b)
50    bl     SYMBOL_NAME(__umodsi3)
51    //  Apply sign of dividend to result and return.
52    eor     r0,     r0, r4, asr #31
53    sub     r0,     r0, r4, asr #31
54    CLEAR_FRAME_AND_RETURN
55#endif
56END_COMPILERRT_FUNCTION(__modsi3)
57
58NO_EXEC_STACK_DIRECTIVE
59
60