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

36 lines
856 B
ArmAsm

//===------- bswapsi2 - Implement bswapsi2 --------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "../assembly.h"
.syntax unified
.text
DEFINE_CODE_STATE
//
// extern uint32_t __bswapsi2(uint32_t);
//
// Reverse all the bytes in a 32-bit integer.
//
.p2align 2
DEFINE_COMPILERRT_FUNCTION(__bswapsi2)
#if __ARM_ARCH < 6
// 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
JMP(lr)
END_COMPILERRT_FUNCTION(__bswapsi2)
NO_EXEC_STACK_DIRECTIVE