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 .text 26#if __ARM_ARCH_ISA_THUMB == 2 27 .thumb 28#endif 29 30@ int __divmodsi4(int divident, int divisor, int *remainder) 31@ Calculate the quotient and remainder of the (signed) division. The return 32@ value is the quotient, the remainder is placed in the variable. 33 34 .p2align 3 35DEFINE_COMPILERRT_FUNCTION(__divmodsi4) 36#if __ARM_ARCH_EXT_IDIV__ 37 tst r1, r1 38 beq LOCAL_LABEL(divzero) 39 mov r3, r0 40 sdiv r0, r3, r1 41 mls r1, r0, r1, r3 42 str r1, [r2] 43 bx lr 44LOCAL_LABEL(divzero): 45 mov r0, #0 46 bx lr 47#else 48 ESTABLISH_FRAME 49// Set aside the sign of the quotient and modulus, and the address for the 50// modulus. 51 eor r4, r0, r1 52 mov r5, r0 53 mov r6, r2 54// Take the absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31). 55 eor ip, r0, r0, asr #31 56 eor lr, r1, r1, asr #31 57 sub r0, ip, r0, asr #31 58 sub r1, lr, r1, asr #31 59// Unsigned divmod: 60 bl SYMBOL_NAME(__udivmodsi4) 61// Apply the sign of quotient and modulus 62 ldr r1, [r6] 63 eor r0, r0, r4, asr #31 64 eor r1, r1, r5, asr #31 65 sub r0, r0, r4, asr #31 66 sub r1, r1, r5, asr #31 67 str r1, [r6] 68 CLEAR_FRAME_AND_RETURN 69#endif 70END_COMPILERRT_FUNCTION(__divmodsi4) 71