NetBSD/sys/arch/riscv/include/byte_swap.h
dennis ca2461272f Shave an instruction from the generated code for the 32 bit byte
swap inline.  Prune 5 or 9 instructions (depending on what you count)
from the 64 bit byte swap inline.
2014-10-28 20:25:36 +00:00

102 lines
2.9 KiB
C

/* $NetBSD: byte_swap.h,v 1.3 2014/10/28 20:25:36 dennis Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _RISCV_BYTE_SWAP_H_
#define _RISCV_BYTE_SWAP_H_
#ifdef _LOCORE
#define BSWAP16(_src, _dst, _tmp) \
andi _dst, _src, 0xff ;\
slli _dst, _dst, 8 ;\
srli _tmp, _src, 8 ;\
and _tmp, _tmp, 0xff ;\
ori _dst, _dst, _tmp
#define BSWAP32(_src, _dst, _tmp) \
li v1, 0xff00 ;\
slli _dst, _src, 24 ;\
srli _tmp, _src, 24 ;\
ori _dst, _dst, _tmp ;\
and _tmp, _src, v1 ;\
slli _tmp, _src, 8 ;\
ori _dst, _dst, _tmp ;\
srli _tmp, _src, 8 ;\
and _tmp, _tmp, v1 ;\
ori _dst, _dst, _tmp
#else
#include <sys/types.h>
__BEGIN_DECLS
#define __BYTE_SWAP_U64_VARIABLE __byte_swap_u64_variable
static __inline uint64_t
__byte_swap_u64_variable(uint64_t v)
{
const uint64_t m1 = 0x0000ffff0000ffffull;
const uint64_t m0 = 0x00ff00ff00ff00ffull;
v = (v >> 32) | (v << 32);
v = ((v >> 16) & m1) | ((v & m1) << 16);
v = ((v >> 8) & m0) | ((v & m0) << 8);
return v;
}
#define __BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable
static __inline uint32_t
__byte_swap_u32_variable(uint32_t v)
{
const uint32_t m = 0xff00ff;
v = (v >> 16) | (v << 16);
v = ((v >> 8) & m) | ((v & m) << 8);
return v;
}
#define __BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable
static __inline uint16_t
__byte_swap_u16_variable(uint16_t v)
{
v &= 0xffff;
v = (v >> 8) | (v << 8);
return v;
}
__END_DECLS
#endif /* _LOCORE */
#endif /* _RISCV_BYTE_SWAP_H_ */