1/*===-- divmodsi4.S - 32-bit signed integer divide and modulus ------------===//
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 __divmodsi4 (32-bit signed integer divide and
11 * modulus) function for the ARM architecture.  A naive digit-by-digit
12 * computation is employed for simplicity.
13 *
14 *===----------------------------------------------------------------------===*/
15
16#include "../assembly.h"
17
18#define ESTABLISH_FRAME    \
19    push   {r4-r7, lr}   ;\
20    add     r7,     sp, #12
21#define CLEAR_FRAME_AND_RETURN \
22    pop    {r4-r7, pc}
23
24.syntax unified
25.align 3
26DEFINE_COMPILERRT_FUNCTION(__divmodsi4)
27#if __ARM_ARCH_7S__
28	tst     r1, r1
29	beq     LOCAL_LABEL(divzero)
30	mov 	r3, r0
31	sdiv	r0, r3, r1
32	mls 	r1, r0, r1, r3
33	str 	r1, [r2]
34	bx  	lr
35LOCAL_LABEL(divzero):
36	mov     r0, #0
37	bx      lr
38#else
39    ESTABLISH_FRAME
40//  Set aside the sign of the quotient and modulus, and the address for the
41//  modulus.
42    eor     r4,     r0, r1
43    mov     r5,     r0
44    mov     r6,     r2
45//  Take the absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
46    eor     ip,     r0, r0, asr #31
47    eor     lr,     r1, r1, asr #31
48    sub     r0,     ip, r0, asr #31
49    sub     r1,     lr, r1, asr #31
50//  Unsigned divmod:
51    bl      SYMBOL_NAME(__udivmodsi4)
52//  Apply the sign of quotient and modulus
53    ldr     r1,    [r6]
54    eor     r0,     r0, r4, asr #31
55    eor     r1,     r1, r5, asr #31
56    sub     r0,     r0, r4, asr #31
57    sub     r1,     r1, r5, asr #31
58    str     r1,    [r6]
59    CLEAR_FRAME_AND_RETURN
60#endif
61