| /* 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 |
| * Copyright (C) 2002 Hewlett-Packard Co |
| * David Mosberger-Tang <davidm@hpl.hp.com> |
| #include <asm/asmmacro.h> |
| GLOBAL_ENTRY(carta_random32) |
| movl a = (16807 << 16) | 16807 |
| pmpyshr2.u t0 = a, seed, 0 |
| pmpyshr2.u t1 = a, seed, 16 |
| dep t0 = 0, hi, 15, 49 // t0 = (hi & 0x7fff) |
| shl t0 = t0, 16 // t0 = (hi & 0x7fff) << 16 |
| shr t1 = hi, 15 // t1 = (hi >> 15) |