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795a3f5279
known constants at compile time rather than at run time. We have a number of nasty hacks around the place to cache ntohl() of constants (eg: nfs). This change allows the compiler to compile-time evaluate ntohl(1) as 0x01000000 rather than having to emit assembler code to do it. This has other smaller flow-on effects because the compiler can see that ntohl(constant) itself has a constant value now and can propagate the compile time evaluation. Obtained from: Ideas from NetBSD and Linux, and some code from NetBSD
183 lines
5.2 KiB
C
183 lines
5.2 KiB
C
/*-
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* Copyright (c) 1987, 1991 Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)endian.h 7.8 (Berkeley) 4/3/91
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* $FreeBSD$
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*/
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#ifndef _MACHINE_ENDIAN_H_
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#define _MACHINE_ENDIAN_H_
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#include <sys/cdefs.h>
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#include <sys/_types.h>
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/*
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* Define the order of 32-bit words in 64-bit words.
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*/
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#define _QUAD_HIGHWORD 1
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#define _QUAD_LOWWORD 0
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/*
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* Definitions for byte order, according to byte significance from low
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* address to high.
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*/
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#define _LITTLE_ENDIAN 1234 /* LSB first: i386, vax */
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#define _BIG_ENDIAN 4321 /* MSB first: 68000, ibm, net */
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#define _PDP_ENDIAN 3412 /* LSB first in word, MSW first in long */
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#define _BYTE_ORDER _LITTLE_ENDIAN
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/*
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* Deprecated variants that don't have enough underscores to be useful in more
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* strict namespaces.
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*/
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#if __BSD_VISIBLE
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#define LITTLE_ENDIAN _LITTLE_ENDIAN
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#define BIG_ENDIAN _BIG_ENDIAN
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#define PDP_ENDIAN _PDP_ENDIAN
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#define BYTE_ORDER _BYTE_ORDER
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#endif
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#ifdef __GNUC__
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#define __word_swap_int_var(x) \
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__extension__ ({ register __uint32_t __X = (x); \
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__asm ("rorl $16, %0" : "+r" (__X)); \
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__X; })
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#ifdef __OPTIMIZE__
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#define __word_swap_int_const(x) \
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((((x) & 0xffff0000) >> 16) | \
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(((x) & 0x0000ffff) << 16))
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#define __word_swap_int(x) (__builtin_constant_p(x) ? \
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__word_swap_int_const(x) : __word_swap_int_var(x))
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#else /* __OPTIMIZE__ */
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#define __word_swap_int(x) __word_swap_int_var(x)
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#endif /* __OPTIMIZE__ */
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#if defined(_KERNEL) && (defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU)) && !defined(I386_CPU)
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#define __byte_swap_int_var(x) \
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__extension__ ({ register __uint32_t __X = (x); \
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__asm ("bswap %0" : "+r" (__X)); \
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__X; })
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#else
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#define __byte_swap_int_var(x) \
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__extension__ ({ register __uint32_t __X = (x); \
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__asm ("xchgb %h0, %b0\n\trorl $16, %0\n\txchgb %h0, %b0" \
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: "+q" (__X)); \
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__X; })
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#endif
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#ifdef __OPTIMIZE__
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#define __byte_swap_int_const(x) \
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((((x) & 0xff000000) >> 24) | \
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(((x) & 0x00ff0000) >> 8) | \
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(((x) & 0x0000ff00) << 8) | \
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(((x) & 0x000000ff) << 24))
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#define __byte_swap_int(x) (__builtin_constant_p(x) ? \
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__byte_swap_int_const(x) : __byte_swap_int_var(x))
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#else /* __OPTIMIZE__ */
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#define __byte_swap_int(x) __byte_swap_int_var(x)
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#endif /* __OPTIMIZE__ */
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#define __byte_swap_word_var(x) \
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__extension__ ({ register __uint16_t __X = (x); \
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__asm ("xchgb %h0, %b0" : "+q" (__X)); \
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__X; })
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#ifdef __OPTIMIZE__
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#define __byte_swap_word_const(x) \
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((((x) & 0xff00) >> 8) | \
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(((x) & 0x00ff) << 8))
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#define __byte_swap_word(x) (__builtin_constant_p(x) ? \
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__byte_swap_word_const(x) : __byte_swap_word_var(x))
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#else /* __OPTIMIZE__ */
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#define __byte_swap_word(x) __byte_swap_word_var(x)
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#endif /* __OPTIMIZE__ */
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static __inline __uint64_t
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__bswap64(__uint64_t _x)
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{
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return ((_x >> 56) | ((_x >> 40) & 0xff00) | ((_x >> 24) & 0xff0000) |
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((_x >> 8) & 0xff000000) | ((_x << 8) & ((__uint64_t)0xff << 32)) |
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((_x << 24) & ((__uint64_t)0xff << 40)) |
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((_x << 40) & ((__uint64_t)0xff << 48)) | ((_x << 56)));
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}
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static __inline __uint32_t
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__bswap32(__uint32_t _x)
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{
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return (__byte_swap_int(_x));
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}
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static __inline __uint16_t
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__bswap16(__uint16_t _x)
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{
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return (__byte_swap_word(_x));
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}
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#define __htonl(x) __bswap32(x)
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#define __htons(x) __bswap16(x)
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#define __ntohl(x) __bswap32(x)
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#define __ntohs(x) __bswap16(x)
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#else /* !__GNUC__ */
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/*
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* No optimizations are available for this compiler. Fall back to
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* non-optimized functions by defining the constant usually used to prevent
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* redefinition.
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*/
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#define _BYTEORDER_FUNC_DEFINED
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#endif /* __GNUC__ */
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#endif /* !_MACHINE_ENDIAN_H_ */
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