| /* |
| * Fast, simple, yet decent quality random number generator based on |
| * a paper by David G. Carta ("Two Fast Implementations of the |
| * `Minimal Standard' Random Number Generator," Communications of the |
| * ACM, January, 1990). |
| * |
| * Copyright (C) 2002 Hewlett-Packard Co |
| * David Mosberger-Tang <davidm@hpl.hp.com> |
| */ |
| |
| #include <asm/asmmacro.h> |
| |
| #define a r2 |
| #define m r3 |
| #define lo r8 |
| #define hi r9 |
| #define t0 r16 |
| #define t1 r17 |
| #define seed r32 |
| |
| GLOBAL_ENTRY(carta_random32) |
| movl a = (16807 << 16) | 16807 |
| ;; |
| pmpyshr2.u t0 = a, seed, 0 |
| pmpyshr2.u t1 = a, seed, 16 |
| ;; |
| unpack2.l t0 = t1, t0 |
| dep m = -1, r0, 0, 31 |
| ;; |
| zxt4 lo = t0 |
| shr.u hi = t0, 32 |
| ;; |
| dep t0 = 0, hi, 15, 49 // t0 = (hi & 0x7fff) |
| ;; |
| shl t0 = t0, 16 // t0 = (hi & 0x7fff) << 16 |
| shr t1 = hi, 15 // t1 = (hi >> 15) |
| ;; |
| add lo = lo, t0 |
| ;; |
| cmp.gtu p6, p0 = lo, m |
| ;; |
| (p6) and lo = lo, m |
| ;; |
| (p6) add lo = 1, lo |
| ;; |
| add lo = lo, t1 |
| ;; |
| cmp.gtu p6, p0 = lo, m |
| ;; |
| (p6) and lo = lo, m |
| ;; |
| (p6) add lo = 1, lo |
| br.ret.sptk.many rp |
| END(carta_random32) |