1//===------- bswapsi2 - Implement bswapsi2 --------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "../assembly.h"
10
11 .syntax unified
12 .text
13 DEFINE_CODE_STATE
14
15//
16// extern uint32_t __bswapsi2(uint32_t);
17//
18// Reverse all the bytes in a 32-bit integer.
19//
20 .p2align 2
21DEFINE_COMPILERRT_FUNCTION(__bswapsi2)
22#if __ARM_ARCH < 6
23 // before armv6 does not have "rev" instruction
24 eor r1, r0, r0, ror #16
25 bic r1, r1, #0xff0000
26 mov r1, r1, lsr #8
27 eor r0, r1, r0, ror #8
28#else
29 rev r0, r0
30#endif
31 JMP(lr)
32END_COMPILERRT_FUNCTION(__bswapsi2)
33
34NO_EXEC_STACK_DIRECTIVE
35
36

source code of compiler-rt/lib/builtins/arm/bswapsi2.S