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 .align 3 26 DEFINE_COMPILERRT_FUNCTION(__divmodsi4) 27 #if __ARM_ARCH_7S__ 28 tst r1, r1 29 beq LOCAL_LABEL(divzero) 30 mov r3, r0 31 sdiv r0, r3, r1 32 mls r1, r0, r1, r3 33 str r1, [r2] 34 bx lr 35 LOCAL_LABEL(divzero): 36 mov r0, #0 37 bx lr 38 #else 39 ESTABLISH_FRAME 40 // Set aside the sign of the quotient and modulus, and the address for the 41 // modulus. 42 eor r4, r0, r1 43 mov r5, r0 44 mov r6, r2 45 // Take the absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31). 46 eor ip, r0, r0, asr #31 47 eor lr, r1, r1, asr #31 48 sub r0, ip, r0, asr #31 49 sub r1, lr, r1, asr #31 50 // Unsigned divmod: 51 bl SYMBOL_NAME(__udivmodsi4) 52 // Apply the sign of quotient and modulus 53 ldr r1, [r6] 54 eor r0, r0, r4, asr #31 55 eor r1, r1, r5, asr #31 56 sub r0, r0, r4, asr #31 57 sub r1, r1, r5, asr #31 58 str r1, [r6] 59 CLEAR_FRAME_AND_RETURN 60 #endif 61
