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1 | /* |
2 | * Copyright (c) 1993 Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 3. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This product includes software developed by the Computer Systems | |
16 | * Engineering Group at Lawrence Berkeley Laboratory. | |
17 | * 4. Neither the name of the University nor of the Laboratory may be used | |
18 | * to endorse or promote products derived from this software without | |
19 | * specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | * SUCH DAMAGE. | |
32 | */ | |
33 | ||
34 | /* | |
35 | * LBL BSD kernel random number generator (used by statclock). | |
36 | * | |
37 | * Written by Steve McCanne & Chris Torek (mccanne@ee.lbl.gov, | |
38 | * torek@ee.lbl.gov), November, 1992. | |
39 | * | |
40 | * This implementation is based on ``Two Fast Implementations of | |
41 | * the "Minimal Standard" Random Number Generator", David G. Carta, | |
42 | * Communications of the ACM, Jan 1990, Vol 33 No 1. | |
43 | */ | |
44 | ||
45 | #ifdef sparc | |
46 | asm("\ | |
47 | .global _kernrand ;\ | |
48 | _kernrand: ;\ | |
49 | sethi %hi(16807), %o1 ;\ | |
50 | wr %o1, %lo(16807), %y ;\ | |
51 | set 0xffff, %o4 ;\ | |
52 | andcc %g0, 0, %o2 ;\ | |
53 | mulscc %o2, %o0, %o2 ;\ | |
54 | mulscc %o2, %o0, %o2 ;\ | |
55 | mulscc %o2, %o0, %o2 ;\ | |
56 | mulscc %o2, %o0, %o2 ;\ | |
57 | mulscc %o2, %o0, %o2 ;\ | |
58 | mulscc %o2, %o0, %o2 ;\ | |
59 | mulscc %o2, %o0, %o2 ;\ | |
60 | mulscc %o2, %o0, %o2 ;\ | |
61 | mulscc %o2, %o0, %o2 ;\ | |
62 | mulscc %o2, %o0, %o2 ;\ | |
63 | mulscc %o2, %o0, %o2 ;\ | |
64 | mulscc %o2, %o0, %o2 ;\ | |
65 | mulscc %o2, %o0, %o2 ;\ | |
66 | mulscc %o2, %o0, %o2 ;\ | |
67 | mulscc %o2, %o0, %o2 ;\ | |
68 | mulscc %o2, %g0, %o2 ;\ | |
69 | rd %y, %o3 ;\ | |
70 | srl %o2, 16, %o1 ;\ | |
71 | and %o4, %o2, %o0 ;\ | |
72 | sll %o0, 15, %o0 ;\ | |
73 | srl %o3, 17, %o3 ;\ | |
74 | or %o3, %o0, %o0 ;\ | |
75 | addcc %o0, %o1, %o0 ;\ | |
76 | bl 1f ;\ | |
77 | sethi %hi(0x7fffffff), %o1 ;\ | |
78 | retl ;\ | |
79 | nop ;\ | |
80 | 1: ;\ | |
81 | or %o1, %lo(0x7fffffff), %o1 ;\ | |
82 | add %o0, 1, %o0 ;\ | |
83 | retl ;\ | |
84 | and %o1, %o0, %o0 "); | |
85 | #else | |
86 | long | |
87 | kernrand(x) | |
88 | register long x; | |
89 | { | |
90 | register long hi, lo, t; | |
91 | ||
92 | hi = x / 127773; | |
93 | lo = x % 127773; | |
94 | t = 16807 * lo - 2836 * hi; | |
95 | if (t > 0) | |
96 | return (t); | |
97 | else | |
98 | return (t + 0x7fffffff); | |
99 | } | |
100 | #endif |