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bswapdi2.S revision 1.1.1.3.4.2 
      1 //===------- bswapdi2 - Implement bswapdi2 --------------------------------===//
      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 #include "../assembly.h"
     11 
     12 	.syntax unified
     13 	.text
     14 #if __ARM_ARCH_ISA_THUMB == 2
     15 	.thumb
     16 #endif
     17 
     18 //
     19 // extern uint64_t __bswapdi2(uint64_t);
     20 //
     21 // Reverse all the bytes in a 64-bit integer.
     22 //
     23 	.p2align 2
     24 DEFINE_COMPILERRT_FUNCTION(__bswapdi2)
     25 #if __ARM_ARCH < 6
     26     // before armv6 does not have "rev" instruction
     27     // r2 = rev(r0)
     28     eor r2, r0, r0, ror #16
     29     bic r2, r2, #0xff0000
     30     mov r2, r2, lsr #8
     31     eor r2, r2, r0, ror #8
     32     // r0 = rev(r1)
     33     eor r0, r1, r1, ror #16
     34     bic r0, r0, #0xff0000
     35     mov r0, r0, lsr #8
     36     eor r0, r0, r1, ror #8
     37 #else
     38     rev r2, r0  // r2 = rev(r0)
     39     rev r0, r1  // r0 = rev(r1)
     40 #endif
     41     mov r1, r2  // r1 = r2 = rev(r0)
     42     JMP(lr)
     43 END_COMPILERRT_FUNCTION(__bswapdi2)
     44