llvm-project/compiler-rt/lib/arm/bswapsi2.S

29 lines
755 B
ArmAsm

//===------- bswapsi2 - Implement bswapsi2 --------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "../assembly.h"
//
// extern uint32_t __bswapsi2(uint32_t);
//
// Reverse all the bytes in a 32-bit integer.
//
.align 2
DEFINE_COMPILERRT_FUNCTION(__bswapsi2)
#if __ARM_ARCH_5TEJ__ || __ARM_ARCH_4T__
// before armv6 does not have "rev" instruction
eor r1, r0, r0, ror #16
bic r1, r1, #0xff0000
mov r1, r1, lsr #8
eor r0, r1, r0, ror #8
#else
rev r0, r0
#endif
bx lr