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divsi3.S revision 1.1.1.3.4.2 
      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 
     33 @ int __divsi3(int divident, int divisor)
     34 @   Calculate and return the quotient of the (signed) division.
     35 
     36 DEFINE_COMPILERRT_FUNCTION(__divsi3)
     37 #if __ARM_ARCH_EXT_IDIV__
     38    tst     r1,r1
     39    beq     LOCAL_LABEL(divzero)
     40    sdiv    r0, r0, r1
     41    bx      lr
     42 LOCAL_LABEL(divzero):
     43    mov     r0,#0
     44    bx      lr
     45 #else
     46 ESTABLISH_FRAME
     47 //  Set aside the sign of the quotient.
     48     eor     r4,     r0, r1
     49 //  Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
     50     eor     r2,     r0, r0, asr #31
     51     eor     r3,     r1, r1, asr #31
     52     sub     r0,     r2, r0, asr #31
     53     sub     r1,     r3, r1, asr #31
     54 //  abs(a) / abs(b)
     55     bl      SYMBOL_NAME(__udivsi3)
     56 //  Apply sign of quotient to result and return.
     57     eor     r0,     r0, r4, asr #31
     58     sub     r0,     r0, r4, asr #31
     59     CLEAR_FRAME_AND_RETURN
     60 #endif
     61 END_COMPILERRT_FUNCTION(__divsi3)
     62