1//===-- divmodsi4.S - 32-bit signed integer divide and 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 __divmodsi4 (32-bit signed integer divide and
10// modulus) function for the ARM architecture.  A naive digit-by-digit
11// computation is employed for simplicity.
12//
13//===----------------------------------------------------------------------===//
14
15#include "../assembly.h"
16
17#define ESTABLISH_FRAME    \
18    push   {r4-r7, lr}   ;\
19    add     r7,     sp, #12
20#define CLEAR_FRAME_AND_RETURN \
21    pop    {r4-r7, pc}
22
23	.syntax unified
24	.text
25  DEFINE_CODE_STATE
26
27@ int __divmodsi4(int divident, int divisor, int *remainder)
28@   Calculate the quotient and remainder of the (signed) division.  The return
29@   value is the quotient, the remainder is placed in the variable.
30
31	.p2align 3
32DEFINE_COMPILERRT_FUNCTION(__divmodsi4)
33#if __ARM_ARCH_EXT_IDIV__
34	tst     r1, r1
35	beq     LOCAL_LABEL(divzero)
36	mov 	r3, r0
37	sdiv	r0, r3, r1
38	mls 	r1, r0, r1, r3
39	str 	r1, [r2]
40	bx  	lr
41LOCAL_LABEL(divzero):
42	mov     r0, #0
43	bx      lr
44#else
45    ESTABLISH_FRAME
46//  Set aside the sign of the quotient and modulus, and the address for the
47//  modulus.
48    eor     r4,     r0, r1
49    mov     r5,     r0
50    mov     r6,     r2
51//  Take the absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
52    eor     ip,     r0, r0, asr #31
53    eor     lr,     r1, r1, asr #31
54    sub     r0,     ip, r0, asr #31
55    sub     r1,     lr, r1, asr #31
56//  Unsigned divmod:
57    bl      SYMBOL_NAME(__udivmodsi4)
58//  Apply the sign of quotient and modulus
59    ldr     r1,    [r6]
60    eor     r0,     r0, r4, asr #31
61    eor     r1,     r1, r5, asr #31
62    sub     r0,     r0, r4, asr #31
63    sub     r1,     r1, r5, asr #31
64    str     r1,    [r6]
65    CLEAR_FRAME_AND_RETURN
66#endif
67END_COMPILERRT_FUNCTION(__divmodsi4)
68
69NO_EXEC_STACK_DIRECTIVE
70
71