xref: /openbsd-src/gnu/llvm/compiler-rt/lib/builtins/arm/divsi3.S (revision 3cab2bb3f667058bece8e38b12449a63a9d73c4b)
1*3cab2bb3Spatrick//===-- divsi3.S - 32-bit signed integer divide ---------------------------===//
2*3cab2bb3Spatrick//
3*3cab2bb3Spatrick// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*3cab2bb3Spatrick// See https://llvm.org/LICENSE.txt for license information.
5*3cab2bb3Spatrick// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*3cab2bb3Spatrick//
7*3cab2bb3Spatrick//===----------------------------------------------------------------------===//
8*3cab2bb3Spatrick//
9*3cab2bb3Spatrick// This file implements the __divsi3 (32-bit signed integer divide) function
10*3cab2bb3Spatrick// for the ARM architecture as a wrapper around the unsigned routine.
11*3cab2bb3Spatrick//
12*3cab2bb3Spatrick//===----------------------------------------------------------------------===//
13*3cab2bb3Spatrick
14*3cab2bb3Spatrick#include "../assembly.h"
15*3cab2bb3Spatrick
16*3cab2bb3Spatrick#define ESTABLISH_FRAME \
17*3cab2bb3Spatrick    push   {r4, r7, lr}    ;\
18*3cab2bb3Spatrick    add     r7,     sp, #4
19*3cab2bb3Spatrick#define CLEAR_FRAME_AND_RETURN \
20*3cab2bb3Spatrick    pop    {r4, r7, pc}
21*3cab2bb3Spatrick
22*3cab2bb3Spatrick   .syntax unified
23*3cab2bb3Spatrick   .text
24*3cab2bb3Spatrick   DEFINE_CODE_STATE
25*3cab2bb3Spatrick
26*3cab2bb3Spatrick	.p2align 3
27*3cab2bb3Spatrick// Ok, APCS and AAPCS agree on 32 bit args, so it's safe to use the same routine.
28*3cab2bb3SpatrickDEFINE_AEABI_FUNCTION_ALIAS(__aeabi_idiv, __divsi3)
29*3cab2bb3Spatrick
30*3cab2bb3Spatrick@ int __divsi3(int divident, int divisor)
31*3cab2bb3Spatrick@   Calculate and return the quotient of the (signed) division.
32*3cab2bb3Spatrick
33*3cab2bb3SpatrickDEFINE_COMPILERRT_FUNCTION(__divsi3)
34*3cab2bb3Spatrick#if __ARM_ARCH_EXT_IDIV__
35*3cab2bb3Spatrick   tst     r1,r1
36*3cab2bb3Spatrick   beq     LOCAL_LABEL(divzero)
37*3cab2bb3Spatrick   sdiv    r0, r0, r1
38*3cab2bb3Spatrick   bx      lr
39*3cab2bb3SpatrickLOCAL_LABEL(divzero):
40*3cab2bb3Spatrick   mov     r0,#0
41*3cab2bb3Spatrick   bx      lr
42*3cab2bb3Spatrick#else
43*3cab2bb3SpatrickESTABLISH_FRAME
44*3cab2bb3Spatrick//  Set aside the sign of the quotient.
45*3cab2bb3Spatrick#  if defined(USE_THUMB_1)
46*3cab2bb3Spatrick    movs    r4,     r0
47*3cab2bb3Spatrick    eors    r4,     r1
48*3cab2bb3Spatrick#  else
49*3cab2bb3Spatrick    eor     r4,     r0, r1
50*3cab2bb3Spatrick#  endif
51*3cab2bb3Spatrick//  Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
52*3cab2bb3Spatrick#  if defined(USE_THUMB_1)
53*3cab2bb3Spatrick    asrs    r2,     r0, #31
54*3cab2bb3Spatrick    asrs    r3,     r1, #31
55*3cab2bb3Spatrick    eors    r0,     r2
56*3cab2bb3Spatrick    eors    r1,     r3
57*3cab2bb3Spatrick    subs    r0,     r0, r2
58*3cab2bb3Spatrick    subs    r1,     r1, r3
59*3cab2bb3Spatrick#  else
60*3cab2bb3Spatrick    eor     r2,     r0, r0, asr #31
61*3cab2bb3Spatrick    eor     r3,     r1, r1, asr #31
62*3cab2bb3Spatrick    sub     r0,     r2, r0, asr #31
63*3cab2bb3Spatrick    sub     r1,     r3, r1, asr #31
64*3cab2bb3Spatrick#  endif
65*3cab2bb3Spatrick//  abs(a) / abs(b)
66*3cab2bb3Spatrick    bl      SYMBOL_NAME(__udivsi3)
67*3cab2bb3Spatrick//  Apply sign of quotient to result and return.
68*3cab2bb3Spatrick#  if defined(USE_THUMB_1)
69*3cab2bb3Spatrick    asrs    r4,     #31
70*3cab2bb3Spatrick    eors    r0,     r4
71*3cab2bb3Spatrick    subs    r0,     r0, r4
72*3cab2bb3Spatrick#  else
73*3cab2bb3Spatrick    eor     r0,     r0, r4, asr #31
74*3cab2bb3Spatrick    sub     r0,     r0, r4, asr #31
75*3cab2bb3Spatrick#  endif
76*3cab2bb3Spatrick    CLEAR_FRAME_AND_RETURN
77*3cab2bb3Spatrick#endif
78*3cab2bb3SpatrickEND_COMPILERRT_FUNCTION(__divsi3)
79*3cab2bb3Spatrick
80*3cab2bb3SpatrickNO_EXEC_STACK_DIRECTIVE
81*3cab2bb3Spatrick
82