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58 lines
1.3 KiB
C
58 lines
1.3 KiB
C
/*
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* Written by Manuel Bouyer <bouyer@netbsd.org>.
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* Public domain.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#if defined(LIBC_SCCS) && !defined(lint)
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static char *rcsid = "$NetBSD: bswap32.c,v 1.1 1997/10/09 15:42:33 bouyer Exp $";
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static char *rcsid = "$NetBSD: bswap64.c,v 1.3 2009/03/16 05:59:21 cegger Exp $";
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#endif
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#include <sys/types.h>
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#undef bswap32
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#undef bswap64
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u_int32_t bswap32(u_int32_t x);
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u_int64_t bswap64(u_int64_t x);
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u_int32_t
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bswap32(u_int32_t x)
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{
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return ((x << 24) & 0xff000000 ) |
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((x << 8) & 0x00ff0000 ) |
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((x >> 8) & 0x0000ff00 ) |
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((x >> 24) & 0x000000ff );
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}
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u_int64_t
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bswap64(u_int64_t x)
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{
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#ifdef _LP64
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/*
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* Assume we have wide enough registers to do it without touching
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* memory.
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*/
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return ( (x << 56) & 0xff00000000000000UL ) |
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( (x << 40) & 0x00ff000000000000UL ) |
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( (x << 24) & 0x0000ff0000000000UL ) |
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( (x << 8) & 0x000000ff00000000UL ) |
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( (x >> 8) & 0x00000000ff000000UL ) |
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( (x >> 24) & 0x0000000000ff0000UL ) |
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( (x >> 40) & 0x000000000000ff00UL ) |
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( (x >> 56) & 0x00000000000000ffUL );
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#else
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/*
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* Split the operation in two 32bit steps.
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*/
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u_int32_t tl, th;
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th = bswap32((u_int32_t)(x & 0x00000000ffffffffULL));
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tl = bswap32((u_int32_t)((x >> 32) & 0x00000000ffffffffULL));
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return ((u_int64_t)th << 32) | tl;
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#endif
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}
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