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WebSVN – planix.SVN – Blame – /os/branches/feature_posix/sys/src/ape/lib/v/rand.c – Rev 2

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#define _RESEARCH_SOURCE
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#include <stdlib.h>
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#include <libv.h>
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/*
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	random number generator from cacm 31 10, oct 88
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	for 32 bit integers (called long here)
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*/
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#ifdef	MAIN
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#define	A	16807
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#define	M	2147483647
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#define	Q	127773
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#define	R	2836
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#else
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#define	A	48271
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#define	M	2147483647
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#define	Q	44488
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#define	R	3399
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#endif
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static long seed = 1;
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void
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srand(unsigned int newseed)
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{
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	seed = newseed;
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}
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long
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lrand(void)
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{
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	long lo, hi, test;
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	hi = seed/Q;
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	lo = seed%Q;
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	test = A*lo - R*hi;
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	if(test > 0)
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		seed = test;
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	else
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		seed = test+M;
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	return(seed);
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}
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int
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rand(void)
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{
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	return lrand()%(RAND_MAX+1);
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}
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#ifdef	MAIN
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main()
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{
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	int i;
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	for(i = 0; i < 10000; i++)
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		rand();
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	if(seed == 1043618065)
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		printf("     rand: pass\n");
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	else
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		printf("*****rand: fail; seed=%u, should be 1043618065\n", seed);
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	exit(0);
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}
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#endif