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#if __ARM_ARCH_ISA_THUMB == 2
25DEFINE_COMPILERRT_THUMB_FUNCTION(__bswapdi2)
26#else
27DEFINE_COMPILERRT_FUNCTION(__bswapdi2)
28#endif
29#if __ARM_ARCH < 6
30    // before armv6 does not have "rev" instruction
31    // r2 = rev(r0)
32    eor r2, r0, r0, ror #16
33    bic r2, r2, #0xff0000
34    mov r2, r2, lsr #8
35    eor r2, r2, r0, ror #8
36    // r0 = rev(r1)
37    eor r0, r1, r1, ror #16
38    bic r0, r0, #0xff0000
39    mov r0, r0, lsr #8
40    eor r0, r0, r1, ror #8
41#else
42    rev r2, r0  // r2 = rev(r0)
43    rev r0, r1  // r0 = rev(r1)
44#endif
45    mov r1, r2  // r1 = r2 = rev(r0)
46    JMP(lr)
47END_COMPILERRT_FUNCTION(__bswapdi2)
48