xref: /aosp_15_r20/external/compiler-rt/lib/builtins/arm/modsi3.S (revision 7c3d14c8b49c529e04be81a3ce6f5cc23712e4c6)
1*7c3d14c8STreehugger Robot/*===-- modsi3.S - 32-bit signed integer modulus --------------------------===//
2*7c3d14c8STreehugger Robot *
3*7c3d14c8STreehugger Robot *                     The LLVM Compiler Infrastructure
4*7c3d14c8STreehugger Robot *
5*7c3d14c8STreehugger Robot * This file is dual licensed under the MIT and the University of Illinois Open
6*7c3d14c8STreehugger Robot * Source Licenses. See LICENSE.TXT for details.
7*7c3d14c8STreehugger Robot *
8*7c3d14c8STreehugger Robot *===----------------------------------------------------------------------===//
9*7c3d14c8STreehugger Robot *
10*7c3d14c8STreehugger Robot * This file implements the __modsi3 (32-bit signed integer modulus) function
11*7c3d14c8STreehugger Robot * for the ARM architecture as a wrapper around the unsigned routine.
12*7c3d14c8STreehugger Robot *
13*7c3d14c8STreehugger Robot *===----------------------------------------------------------------------===*/
14*7c3d14c8STreehugger Robot
15*7c3d14c8STreehugger Robot#include "../assembly.h"
16*7c3d14c8STreehugger Robot
17*7c3d14c8STreehugger Robot#define ESTABLISH_FRAME \
18*7c3d14c8STreehugger Robot    push   {r4, r7, lr}    ;\
19*7c3d14c8STreehugger Robot    add     r7,     sp, #4
20*7c3d14c8STreehugger Robot#define CLEAR_FRAME_AND_RETURN \
21*7c3d14c8STreehugger Robot    pop    {r4, r7, pc}
22*7c3d14c8STreehugger Robot
23*7c3d14c8STreehugger Robot	.syntax unified
24*7c3d14c8STreehugger Robot	.text
25*7c3d14c8STreehugger Robot#if __ARM_ARCH_ISA_THUMB == 2
26*7c3d14c8STreehugger Robot	.thumb
27*7c3d14c8STreehugger Robot#endif
28*7c3d14c8STreehugger Robot
29*7c3d14c8STreehugger Robot@ int __modsi3(int divident, int divisor)
30*7c3d14c8STreehugger Robot@   Calculate and return the remainder of the (signed) division.
31*7c3d14c8STreehugger Robot
32*7c3d14c8STreehugger Robot	.p2align 3
33*7c3d14c8STreehugger Robot#if __ARM_ARCH_ISA_THUMB == 2
34*7c3d14c8STreehugger RobotDEFINE_COMPILERRT_THUMB_FUNCTION(__modsi3)
35*7c3d14c8STreehugger Robot#else
36*7c3d14c8STreehugger RobotDEFINE_COMPILERRT_FUNCTION(__modsi3)
37*7c3d14c8STreehugger Robot#endif
38*7c3d14c8STreehugger Robot#if __ARM_ARCH_EXT_IDIV__
39*7c3d14c8STreehugger Robot	tst     r1, r1
40*7c3d14c8STreehugger Robot	beq     LOCAL_LABEL(divzero)
41*7c3d14c8STreehugger Robot	sdiv	r2, r0, r1
42*7c3d14c8STreehugger Robot	mls 	r0, r2, r1, r0
43*7c3d14c8STreehugger Robot	bx      lr
44*7c3d14c8STreehugger RobotLOCAL_LABEL(divzero):
45*7c3d14c8STreehugger Robot	mov     r0, #0
46*7c3d14c8STreehugger Robot	bx      lr
47*7c3d14c8STreehugger Robot#else
48*7c3d14c8STreehugger Robot    ESTABLISH_FRAME
49*7c3d14c8STreehugger Robot    //  Set aside the sign of the dividend.
50*7c3d14c8STreehugger Robot    mov     r4,     r0
51*7c3d14c8STreehugger Robot    //  Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
52*7c3d14c8STreehugger Robot    eor     r2,     r0, r0, asr #31
53*7c3d14c8STreehugger Robot    eor     r3,     r1, r1, asr #31
54*7c3d14c8STreehugger Robot    sub     r0,     r2, r0, asr #31
55*7c3d14c8STreehugger Robot    sub     r1,     r3, r1, asr #31
56*7c3d14c8STreehugger Robot    //  abs(a) % abs(b)
57*7c3d14c8STreehugger Robot    bl     SYMBOL_NAME(__umodsi3)
58*7c3d14c8STreehugger Robot    //  Apply sign of dividend to result and return.
59*7c3d14c8STreehugger Robot    eor     r0,     r0, r4, asr #31
60*7c3d14c8STreehugger Robot    sub     r0,     r0, r4, asr #31
61*7c3d14c8STreehugger Robot    CLEAR_FRAME_AND_RETURN
62*7c3d14c8STreehugger Robot#endif
63*7c3d14c8STreehugger RobotEND_COMPILERRT_FUNCTION(__modsi3)
64*7c3d14c8STreehugger Robot
65*7c3d14c8STreehugger RobotNO_EXEC_STACK_DIRECTIVE
66*7c3d14c8STreehugger Robot
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