| /* SPDX-License-Identifier: GPL-2.0 */ | |
| /* | |
| * 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) |