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 .p2align 3 31 DEFINE_COMPILERRT_FUNCTION(__divmodsi4) 32 #if __ARM_ARCH_EXT_IDIV__ 33 tst r1, r1 34 beq LOCAL_LABEL(divzero) 35 mov r3, r0 36 sdiv r0, r3, r1 37 mls r1, r0, r1, r3 38 str r1, [r2] 39 bx lr 40 LOCAL_LABEL(divzero): 41 mov r0, #0 42 bx lr 43 #else 44 ESTABLISH_FRAME 45 // Set aside the sign of the quotient and modulus, and the address for the 46 // modulus. 47 eor r4, r0, r1 48 mov r5, r0 49 mov r6, r2 50 // Take the absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31). 51 eor ip, r0, r0, asr #31 52 eor lr, r1, r1, asr #31 53 sub r0, ip, r0, asr #31 54 sub r1, lr, r1, asr #31 55 // Unsigned divmod: 56 bl SYMBOL_NAME(__udivmodsi4) 57 // Apply the sign of quotient and modulus 58 ldr r1, [r6] 59 eor r0, r0, r4, asr #31 60 eor r1, r1, r5, asr #31 61 sub r0, r0, r4, asr #31 62 sub r1, r1, r5, asr #31 63 str r1, [r6] 64 CLEAR_FRAME_AND_RETURN 65 #endif 66 END_COMPILERRT_FUNCTION(__divmodsi4) 67
