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