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      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, lr}
     19 #define CLEAR_FRAME_AND_RETURN \
     20     pop    {r4, pc}
     21 
     22 	.syntax unified
     23 	.text
     24 #if __ARM_ARCH_ISA_THUMB == 2
     25 	.thumb
     26 #endif
     27 
     28 	.p2align 3
     29 // Ok, APCS and AAPCS agree on 32 bit args, so it's safe to use the same routine.
     30 DEFINE_AEABI_FUNCTION_ALIAS(__aeabi_idiv, __divsi3)
     31 
     32 @ int __divsi3(int divident, int divisor)
     33 @   Calculate and return the quotient of the (signed) division.
     34 
     35 #if __ARM_ARCH_ISA_THUMB == 2
     36 DEFINE_COMPILERRT_THUMB_FUNCTION(__divsi3)
     37 #else
     38 DEFINE_COMPILERRT_FUNCTION(__divsi3)
     39 #endif
     40 #if __ARM_ARCH_EXT_IDIV__
     41    tst     r1,r1
     42    beq     LOCAL_LABEL(divzero)
     43    sdiv    r0, r0, r1
     44    bx      lr
     45 LOCAL_LABEL(divzero):
     46    mov     r0,#0
     47    bx      lr
     48 #else
     49 ESTABLISH_FRAME
     50 //  Set aside the sign of the quotient.
     51     eor     r4,     r0, r1
     52 //  Take absolute value of a and b via abs(x) = (x^(x >> 31)) - (x >> 31).
     53     eor     r2,     r0, r0, asr #31
     54     eor     r3,     r1, r1, asr #31
     55     sub     r0,     r2, r0, asr #31
     56     sub     r1,     r3, r1, asr #31
     57 //  abs(a) / abs(b)
     58     bl      SYMBOL_NAME(__udivsi3)
     59 //  Apply sign of quotient to result and return.
     60     eor     r0,     r0, r4, asr #31
     61     sub     r0,     r0, r4, asr #31
     62     CLEAR_FRAME_AND_RETURN
     63 #endif
     64 END_COMPILERRT_FUNCTION(__divsi3)
     65