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bswapdi2.S revision 1.1.1.1 
      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 //
     13 // extern uint64_t __bswapdi2(uint64_t);
     14 //
     15 // Reverse all the bytes in a 64-bit integer.
     16 //
     17 .align 2
     18 DEFINE_COMPILERRT_FUNCTION(__bswapdi2)
     19 #if __ARM_ARCH < 6
     20     // before armv6 does not have "rev" instruction
     21     // r2 = rev(r0)
     22     eor r2, r0, r0, ror #16
     23     bic r2, r2, #0xff0000
     24     mov r2, r2, lsr #8
     25     eor r2, r2, r0, ror #8
     26     // r0 = rev(r1)
     27     eor r0, r1, r1, ror #16
     28     bic r0, r0, #0xff0000
     29     mov r0, r0, lsr #8
     30     eor r0, r0, r1, ror #8
     31 #else
     32     rev r2, r0  // r2 = rev(r0)
     33     rev r0, r1  // r0 = rev(r1)
     34 #endif
     35     mov r1, r2  // r1 = r2 = rev(r0)
     36     JMP(lr)
     37 END_COMPILERRT_FUNCTION(__bswapdi2)
     38