minix/sys/arch/arm/include/byte_swap.h

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/* $NetBSD: byte_swap.h,v 1.12 2012/09/05 01:03:53 matt Exp $ */
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/*-
* Copyright (c) 1997, 1999, 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Charles M. Hannum, Neil A. Carson, and Jason R. Thorpe.
*
* 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 _ARM_BYTE_SWAP_H_
#define _ARM_BYTE_SWAP_H_
#ifdef _LOCORE
#if defined(_ARM_ARCH_6) || defined(_ARM_ARCH_7)
#define BSWAP16(_src, _dst, _tmp) \
rev16 _dst, _src
#define BSWAP32(_src, _dst, _tmp) \
rev _dst, _src
#else
#define BSWAP16(_src, _dst, _tmp) \
mov _tmp, _src, ror #8 ;\
orr _tmp, _tmp, _tmp, lsr #16 ;\
bic _dst, _tmp, _tmp, lsl #16
#define BSWAP32(_src, _dst, _tmp) \
eor _tmp, _src, _src, ror #16 ;\
bic _tmp, _tmp, #0x00FF0000 ;\
mov _dst, _src, ror #8 ;\
eor _dst, _dst, _tmp, lsr #8
#endif
#else
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#ifdef __GNUC__
#include <sys/types.h>
__BEGIN_DECLS
#define __BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable
static __inline uint32_t
__byte_swap_u32_variable(uint32_t v)
{
uint32_t t1;
#ifdef _ARM_ARCH_6
if (!__builtin_constant_p(v)) {
__asm("rev\t%0, %1" : "=r" (v) : "0" (v));
return v;
}
#endif
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t1 = v ^ ((v << 16) | (v >> 16));
t1 &= 0xff00ffffU;
v = (v >> 8) | (v << 24);
v ^= (t1 >> 8);
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return (v);
}
#define __BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable
static __inline uint16_t
__byte_swap_u16_variable(uint16_t v)
{
#ifdef _ARM_ARCH_6
if (!__builtin_constant_p(v)) {
__asm("rev16\t%0, %1" : "=r" (v) : "0" (v));
return v;
}
#elif !defined(__thumb__) && 0 /* gcc produces decent code for this */
if (!__builtin_constant_p(v)) {
uint32_t v0 = v;
__asm volatile(
"mov %0, %1, ror #8\n"
"orr %0, %0, %0, lsr #16\n"
"bic %0, %0, %0, lsl #16"
: "=&r" (v0)
: "0" (v0));
return v0;
}
#endif
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v &= 0xffff;
v = (v >> 8) | (v << 8);
return (v);
}
__END_DECLS
#endif
#endif /* _LOCORE */
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#endif /* _ARM_BYTE_SWAP_H_ */