| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * linux/arch/arm26/lib/delay.S |
| 3 | * |
| 4 | * Copyright (C) 1995, 1996 Russell King |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | */ |
| 10 | #include <linux/linkage.h> |
| 11 | #include <asm/assembler.h> |
| 12 | .text |
| 13 | |
| 14 | LC0: .word loops_per_jiffy |
| 15 | |
| 16 | /* |
| 17 | * 0 <= r0 <= 2000 |
| 18 | */ |
| 19 | ENTRY(udelay) |
| 20 | mov r2, #0x6800 |
| 21 | orr r2, r2, #0x00db |
| 22 | mul r1, r0, r2 |
| 23 | ldr r2, LC0 |
| 24 | ldr r2, [r2] |
| 25 | mov r1, r1, lsr #11 |
| 26 | mov r2, r2, lsr #11 |
| 27 | mul r0, r1, r2 |
| 28 | movs r0, r0, lsr #6 |
| 29 | RETINSTR(moveq,pc,lr) |
| 30 | |
| 31 | /* |
| 32 | * loops = (r0 * 0x10c6 * 100 * loops_per_jiffy) / 2^32 |
| 33 | * |
| 34 | * Oh, if only we had a cycle counter... |
| 35 | */ |
| 36 | |
| 37 | @ Delay routine |
| 38 | ENTRY(__delay) |
| 39 | subs r0, r0, #1 |
| 40 | #if 0 |
| 41 | RETINSTR(movls,pc,lr) |
| 42 | subs r0, r0, #1 |
| 43 | RETINSTR(movls,pc,lr) |
| 44 | subs r0, r0, #1 |
| 45 | RETINSTR(movls,pc,lr) |
| 46 | subs r0, r0, #1 |
| 47 | RETINSTR(movls,pc,lr) |
| 48 | subs r0, r0, #1 |
| 49 | RETINSTR(movls,pc,lr) |
| 50 | subs r0, r0, #1 |
| 51 | RETINSTR(movls,pc,lr) |
| 52 | subs r0, r0, #1 |
| 53 | RETINSTR(movls,pc,lr) |
| 54 | subs r0, r0, #1 |
| 55 | #endif |
| 56 | bhi __delay |
| 57 | RETINSTR(mov,pc,lr) |