jehanne/sys/src/lib/jehanne/port/frand.c

27 lines
646 B
C

/*
* This file is part of the UCB release of Plan 9. It is subject to the license
* terms in the LICENSE file found in the top-level directory of this
* distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
* part of the UCB release of Plan 9, including this file, may be copied,
* modified, propagated, or distributed except according to the terms contained
* in the LICENSE file.
*/
#include <u.h>
#include <libc.h>
#define MASK 0x7fffffffL
#define NORM (1.0/(1.0+MASK))
double
jehanne_frand(void)
{
double x;
do {
x = jehanne_lrand() * NORM;
x = (x + jehanne_lrand()) * NORM;
} while(x >= 1);
return x;
}