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Move random() from kernel.

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This commit is contained in:
mycroft 1998-02-22 09:33:27 +00:00
parent bb0363853f
commit 8a66afbcba
2 changed files with 90 additions and 2 deletions
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4
sys/lib/libkern/arch/sparc/Makefile.inc
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@ -1,4 +1,4 @@
# $NetBSD: Makefile.inc,v 1.21 1998/02/22 06:57:31 mycroft Exp $
# $NetBSD: Makefile.inc,v 1.22 1998/02/22 09:33:27 mycroft Exp $
SRCS+= __main.c __assert.c \
imax.c imin.c lmax.c lmin.c max.c min.c ulmax.c ulmin.c \
@ -8,7 +8,7 @@ SRCS+= __main.c __assert.c \
strcat.c strcmp.c strcpy.c strlen.S strncasecmp.c strncmp.c strncpy.c \
scanc.c skpc.c \
htonl.S htons.S ntohl.S ntohs.S \
random.c
random.S
SRCS+= umul.S mul.S rem.S sdiv.S udiv.S umul.S urem.S
SRCS+= mul.S saveregs.S umul.S

88
sys/lib/libkern/arch/sparc/random.S Normal file
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@ -0,0 +1,88 @@
/* $NetBSD: random.S,v 1.1 1998/02/22 09:33:27 mycroft Exp $ */
/*
* Copyright (c) 1990,1993 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Here is a very good random number generator. This implementation is
* based on ``Two Fast Implementations of the "Minimal Standard" Random
* Number Generator'', David G. Carta, Communications of the ACM, Jan 1990,
* Vol 33 No 1. Do NOT modify this code unless you have a very thorough
* understanding of the algorithm. It's trickier than you think. If
* you do change it, make sure that its 10,000'th invocation returns
* 1043618065.
*
* Here is easier-to-decipher pseudocode:
*
* p = (16807*seed)<30:0> # e.g., the low 31 bits of the product
* q = (16807*seed)<62:31> # e.g., the high 31 bits starting at bit 32
* if (p + q < 2^31)
* seed = p + q
* else
* seed = ((p + q) & (2^31 - 1)) + 1
* return (seed);
*
* The result is in (0,2^31), e.g., it's always positive.
*/
#include <machine/asm.h>
.data
randseed:
.long 1
.text
ENTRY(random)
sethi %hi(16807), %o1
wr %o1, %lo(16807), %y
sethi %hi(randseed), %g1
ld [%g1 + %lo(randseed)], %o0
andcc %g0, 0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %o0, %o2
mulscc %o2, %g0, %o2
rd %y, %o3
srl %o2, 16, %o1
set 0xffff, %o4
and %o4, %o2, %o0
sll %o0, 15, %o0
srl %o3, 17, %o3
or %o3, %o0, %o0
addcc %o0, %o1, %o0
bneg 1f
sethi %hi(0x7fffffff), %o1
retl
st %o0, [%g1 + %lo(randseed)]
1:
or %o1, %lo(0x7fffffff), %o1
add %o0, 1, %o0
and %o1, %o0, %o0
retl
st %o0, [%g1 + %lo(randseed)]