bswapdi2.S revision 2d1fdb26e458c4ddc04155c1d421bced3ba90cd0 
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.p2align 2
18DEFINE_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)
37END_COMPILERRT_FUNCTION(__bswapdi2)
38