1 a8a775ab 2017-09-01 0intro #include	<u.h>
 2 a8a775ab 2017-09-01 0intro #include	<libc.h>
 3 a8a775ab 2017-09-01 0intro 
 4 a8a775ab 2017-09-01 0intro #define	MASK	0x7fffffffL
 5 a8a775ab 2017-09-01 0intro #define	NORM	(1.0/(1.0+MASK))
 6 a8a775ab 2017-09-01 0intro 
 7 a8a775ab 2017-09-01 0intro double
 8 a8a775ab 2017-09-01 0intro p9frand(void)
 9 a8a775ab 2017-09-01 0intro {
10 a8a775ab 2017-09-01 0intro 	double x;
11 a8a775ab 2017-09-01 0intro 
12 a8a775ab 2017-09-01 0intro 	do {
13 a8a775ab 2017-09-01 0intro 		x = lrand() * NORM;
14 a8a775ab 2017-09-01 0intro 		x = (x + lrand()) * NORM;
15 a8a775ab 2017-09-01 0intro 	} while(x >= 1);
16 a8a775ab 2017-09-01 0intro 	return x;
17 a8a775ab 2017-09-01 0intro }