diff options
Diffstat (limited to 'libc/stdlib/_rand48.c')
| -rw-r--r-- | libc/stdlib/_rand48.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/libc/stdlib/_rand48.c b/libc/stdlib/_rand48.c new file mode 100644 index 0000000..7c950f7 --- /dev/null +++ b/libc/stdlib/_rand48.c @@ -0,0 +1,47 @@ +/* $OpenBSD: _rand48.c,v 1.3 2005/08/08 08:05:36 espie Exp $ */ +/* + * Copyright (c) 1993 Martin Birgmeier + * All rights reserved. + * + * You may redistribute unmodified or modified versions of this source + * code provided that the above copyright notice and this and the + * following conditions are retained. + * + * This software is provided ``as is'', and comes with no warranties + * of any kind. I shall in no event be liable for anything that happens + * to anyone/anything when using this software. + */ + +#include "rand48.h" + +unsigned short __rand48_seed[3] = { + RAND48_SEED_0, + RAND48_SEED_1, + RAND48_SEED_2 +}; +unsigned short __rand48_mult[3] = { + RAND48_MULT_0, + RAND48_MULT_1, + RAND48_MULT_2 +}; +unsigned short __rand48_add = RAND48_ADD; + +void +__dorand48(unsigned short xseed[3]) +{ + unsigned long accu; + unsigned short temp[2]; + + accu = (unsigned long) __rand48_mult[0] * (unsigned long) xseed[0] + + (unsigned long) __rand48_add; + temp[0] = (unsigned short) accu; /* lower 16 bits */ + accu >>= sizeof(unsigned short) * 8; + accu += (unsigned long) __rand48_mult[0] * (unsigned long) xseed[1] + + (unsigned long) __rand48_mult[1] * (unsigned long) xseed[0]; + temp[1] = (unsigned short) accu; /* middle 16 bits */ + accu >>= sizeof(unsigned short) * 8; + accu += __rand48_mult[0] * xseed[2] + __rand48_mult[1] * xseed[1] + __rand48_mult[2] * xseed[0]; + xseed[0] = temp[0]; + xseed[1] = temp[1]; + xseed[2] = (unsigned short) accu; +} |