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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/ia64/lib/carta_random.S
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/ia64/lib/carta_random.S')
-rw-r--r--arch/ia64/lib/carta_random.S54
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/ia64/lib/carta_random.S b/arch/ia64/lib/carta_random.S
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1/*
2 * Fast, simple, yet decent quality random number generator based on
3 * a paper by David G. Carta ("Two Fast Implementations of the
4 * `Minimal Standard' Random Number Generator," Communications of the
5 * ACM, January, 1990).
6 *
7 * Copyright (C) 2002 Hewlett-Packard Co
8 * David Mosberger-Tang <davidm@hpl.hp.com>
9 */
10
11#include <asm/asmmacro.h>
12
13#define a r2
14#define m r3
15#define lo r8
16#define hi r9
17#define t0 r16
18#define t1 r17
19#define seed r32
20
21GLOBAL_ENTRY(carta_random32)
22 movl a = (16807 << 16) | 16807
23 ;;
24 pmpyshr2.u t0 = a, seed, 0
25 pmpyshr2.u t1 = a, seed, 16
26 ;;
27 unpack2.l t0 = t1, t0
28 dep m = -1, r0, 0, 31
29 ;;
30 zxt4 lo = t0
31 shr.u hi = t0, 32
32 ;;
33 dep t0 = 0, hi, 15, 49 // t0 = (hi & 0x7fff)
34 ;;
35 shl t0 = t0, 16 // t0 = (hi & 0x7fff) << 16
36 shr t1 = hi, 15 // t1 = (hi >> 15)
37 ;;
38 add lo = lo, t0
39 ;;
40 cmp.gtu p6, p0 = lo, m
41 ;;
42(p6) and lo = lo, m
43 ;;
44(p6) add lo = 1, lo
45 ;;
46 add lo = lo, t1
47 ;;
48 cmp.gtu p6, p0 = lo, m
49 ;;
50(p6) and lo = lo, m
51 ;;
52(p6) add lo = 1, lo
53 br.ret.sptk.many rp
54END(carta_random32)