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/* $OpenBSD: _rand48.c,v 1.3 2005/08/08 08:05:36 espie 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 "rand48.h" |
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unsigned short __rand48_seed[3] = { |
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RAND48_SEED_0, |
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RAND48_SEED_1, |
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RAND48_SEED_2 |
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}; |
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unsigned short __rand48_mult[3] = { |
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RAND48_MULT_0, |
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RAND48_MULT_1, |
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RAND48_MULT_2 |
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}; |
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unsigned short __rand48_add = RAND48_ADD; |
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void |
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__dorand48(unsigned short xseed[3]) |
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{ |
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unsigned long accu; |
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unsigned short temp[2]; |
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accu = (unsigned long) __rand48_mult[0] * (unsigned long) xseed[0] + |
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(unsigned long) __rand48_add; |
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temp[0] = (unsigned short) accu; /* lower 16 bits */ |
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accu >>= sizeof(unsigned short) * 8; |
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accu += (unsigned long) __rand48_mult[0] * (unsigned long) xseed[1] + |
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(unsigned long) __rand48_mult[1] * (unsigned long) xseed[0]; |
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temp[1] = (unsigned short) accu; /* middle 16 bits */ |
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accu >>= sizeof(unsigned short) * 8; |
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accu += __rand48_mult[0] * xseed[2] + __rand48_mult[1] * xseed[1] + __rand48_mult[2] * xseed[0]; |
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xseed[0] = temp[0]; |
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xseed[1] = temp[1]; |
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xseed[2] = (unsigned short) accu; |
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} |