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-r6, lr} 20#define CLEAR_FRAME_AND_RETURN \ 21 pop {r4-r6, pc} 22 23 .syntax unified 24 .text 25#if __ARM_ARCH_ISA_THUMB == 2 26 .thumb 27#endif 28 29@ int __divmodsi4(int divident, int divisor, int *remainder) 30@ Calculate the quotient and remainder of the (signed) division. The return 31@ value is the quotient, the remainder is placed in the variable. 32 33 .p2align 3 34#if __ARM_ARCH_ISA_THUMB == 2 35DEFINE_COMPILERRT_THUMB_FUNCTION(__divmodsi4) 36#else 37DEFINE_COMPILERRT_FUNCTION(__divmodsi4) 38#endif 39#if __ARM_ARCH_EXT_IDIV__ 40 tst r1, r1 41 beq LOCAL_LABEL(divzero) 42 mov r3, r0 43 sdiv r0, r3, r1 44 mls r1, r0, r1, r3 45 str r1, [r2] 46 bx lr 47LOCAL_LABEL(divzero): 48 mov r0, #0 49 bx lr 50#else 51 ESTABLISH_FRAME 52// Set aside the sign of the quotient and modulus, and the address for the 53// modulus. 54 eor r4, r0, r1 55 mov r5, r0 56 mov r6, r2 57// Take the absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31). 58 eor ip, r0, r0, asr #31 59 eor lr, r1, r1, asr #31 60 sub r0, ip, r0, asr #31 61 sub r1, lr, r1, asr #31 62// Unsigned divmod: 63 bl SYMBOL_NAME(__udivmodsi4) 64// Apply the sign of quotient and modulus 65 ldr r1, [r6] 66 eor r0, r0, r4, asr #31 67 eor r1, r1, r5, asr #31 68 sub r0, r0, r4, asr #31 69 sub r1, r1, r5, asr #31 70 str r1, [r6] 71 CLEAR_FRAME_AND_RETURN 72#endif 73END_COMPILERRT_FUNCTION(__divmodsi4) 74