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divsi3.S revision 1.1.1.1.2.1 
      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 .p2align 3
     25 // Ok, APCS and AAPCS agree on 32 bit args, so it's safe to use the same routine.
     26 DEFINE_AEABI_FUNCTION_ALIAS(__aeabi_idiv, __divsi3)
     27 DEFINE_COMPILERRT_FUNCTION(__divsi3)
     28 #if __ARM_ARCH_EXT_IDIV__
     29    tst     r1,r1
     30    beq     LOCAL_LABEL(divzero)
     31    sdiv    r0, r0, r1
     32    bx      lr
     33 LOCAL_LABEL(divzero):
     34    mov     r0,#0
     35    bx      lr
     36 #else
     37 ESTABLISH_FRAME
     38 //  Set aside the sign of the quotient.
     39     eor     r4,     r0, r1
     40 //  Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
     41     eor     r2,     r0, r0, asr #31
     42     eor     r3,     r1, r1, asr #31
     43     sub     r0,     r2, r0, asr #31
     44     sub     r1,     r3, r1, asr #31
     45 //  abs(a) / abs(b)
     46     bl      SYMBOL_NAME(__udivsi3)
     47 //  Apply sign of quotient to result and return.
     48     eor     r0,     r0, r4, asr #31
     49     sub     r0,     r0, r4, asr #31
     50     CLEAR_FRAME_AND_RETURN
     51 #endif
     52 END_COMPILERRT_FUNCTION(__divsi3)
     53