1 /*===-- modsi3.S - 32-bit signed integer 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 __modsi3 (32-bit signed integer modulus) function 11 * for the ARM architecture as a wrapper around the unsigned routine. 12 * 13 *===----------------------------------------------------------------------===*/ 14 15 #include "../assembly.h" 16 17 #define ESTABLISH_FRAME \ 18 push {r4, r7, lr} ;\ 19 add r7, sp, #4 20 #define CLEAR_FRAME_AND_RETURN \ 21 pop {r4, r7, pc} 22 23 .syntax unified 24 .text 25 #if __ARM_ARCH_ISA_THUMB == 2 26 .thumb 27 #endif 28 29 @ int __modsi3(int divident, int divisor) 30 @ Calculate and return the remainder of the (signed) division. 31 32 .p2align 3 33 #if __ARM_ARCH_ISA_THUMB == 2 34 DEFINE_COMPILERRT_THUMB_FUNCTION(__modsi3) 35 #else 36 DEFINE_COMPILERRT_FUNCTION(__modsi3) 37 #endif 38 #if __ARM_ARCH_EXT_IDIV__ 39 tst r1, r1 40 beq LOCAL_LABEL(divzero) 41 sdiv r2, r0, r1 42 mls r0, r2, r1, r0 43 bx lr 44 LOCAL_LABEL(divzero): 45 mov r0, #0 46 bx lr 47 #else 48 ESTABLISH_FRAME 49 // Set aside the sign of the dividend. 50 mov r4, r0 51 // Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31). 52 eor r2, r0, r0, asr #31 53 eor r3, r1, r1, asr #31 54 sub r0, r2, r0, asr #31 55 sub r1, r3, r1, asr #31 56 // abs(a) % abs(b) 57 bl SYMBOL_NAME(__umodsi3) 58 // Apply sign of dividend to result and return. 59 eor r0, r0, r4, asr #31 60 sub r0, r0, r4, asr #31 61 CLEAR_FRAME_AND_RETURN 62 #endif 63 END_COMPILERRT_FUNCTION(__modsi3) 64
