48 lines
1.2 KiB
C
48 lines
1.2 KiB
C
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/* $NetBSD: erand48_ieee754.c,v 1.2 2006/03/31 11:42:31 drochner Exp $ */
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/*
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* Copyright (c) 1993 Martin Birgmeier
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* All rights reserved.
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*
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* You may redistribute unmodified or modified versions of this source
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* code provided that the above copyright notice and this and the
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* following conditions are retained.
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*
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* This software is provided ``as is'', and comes with no warranties
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* of any kind. I shall in no event be liable for anything that happens
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* to anyone/anything when using this software.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: erand48_ieee754.c,v 1.2 2006/03/31 11:42:31 drochner Exp $");
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#endif /* LIBC_SCCS and not lint */
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#include "namespace.h"
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#include <assert.h>
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#include <machine/ieee.h>
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#include "rand48.h"
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#ifdef __weak_alias
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__weak_alias(erand48,_erand48)
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#endif
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double
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erand48(unsigned short xseed[3])
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{
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union ieee_double_u u;
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_DIAGASSERT(xseed != NULL);
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__dorand48(xseed);
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u.dblu_dbl.dbl_sign = 0;
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u.dblu_dbl.dbl_exp = DBL_EXP_BIAS; /* so we get [1,2) */
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u.dblu_dbl.dbl_frach = ((unsigned int)xseed[2] << 4)
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| ((unsigned int)xseed[1] >> 12);
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u.dblu_dbl.dbl_fracl = (((unsigned int)xseed[1] & 0x0fff) << 20)
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| ((unsigned int)xseed[0] << 4);
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return (u.dblu_d - 1);
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}
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