1 /*===-- divsi3.S - 32-bit signed integer divide ---------------------------===// 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 __divsi3 (32-bit signed integer divide) 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 .p2align 3 30 // Ok, APCS and AAPCS agree on 32 bit args, so it's safe to use the same routine. 31 DEFINE_AEABI_FUNCTION_ALIAS(__aeabi_idiv, __divsi3) 32 DEFINE_COMPILERRT_FUNCTION(__divsi3) 33 #if __ARM_ARCH_EXT_IDIV__ 34 tst r1,r1 35 beq LOCAL_LABEL(divzero) 36 sdiv r0, r0, r1 37 bx lr 38 LOCAL_LABEL(divzero): 39 mov r0,#0 40 bx lr 41 #else 42 ESTABLISH_FRAME 43 // Set aside the sign of the quotient. 44 eor r4, r0, r1 45 // Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31). 46 eor r2, r0, r0, asr #31 47 eor r3, r1, r1, asr #31 48 sub r0, r2, r0, asr #31 49 sub r1, r3, r1, asr #31 50 // abs(a) / abs(b) 51 bl SYMBOL_NAME(__udivsi3) 52 // Apply sign of quotient to result and return. 53 eor r0, r0, r4, asr #31 54 sub r0, r0, r4, asr #31 55 CLEAR_FRAME_AND_RETURN 56 #endif 57 END_COMPILERRT_FUNCTION(__divsi3) 58
