diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /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.S | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/ia64/lib/carta_random.S b/arch/ia64/lib/carta_random.S new file mode 100644 index 000000000000..d0674c360364 --- /dev/null +++ b/arch/ia64/lib/carta_random.S | |||
@@ -0,0 +1,54 @@ | |||
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 | |||
21 | GLOBAL_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 | ||
54 | END(carta_random32) | ||