projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * linux/arch/arm/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 r0, r2, r0 | |
| 23 | ENTRY(__const_udelay) @ 0 <= r0 <= 0x01ffffff | |
| 24 | ldr r2, LC0 | |
| 25 | ldr r2, [r2] @ max = 0x0fffffff | |
| 26 | mov r0, r0, lsr #11 @ max = 0x00003fff | |
| 27 | mov r2, r2, lsr #11 @ max = 0x0003ffff | |
| 28 | mul r0, r2, r0 @ max = 2^32-1 | |
| 29 | movs r0, r0, lsr #6 | |
| 30 | RETINSTR(moveq,pc,lr) | |
| 31 | ||
| 32 | /* | |
| 33 | * loops = (r0 * 0x10c6 * 100 * loops_per_jiffy) / 2^32 | |
| 34 | * | |
| 35 | * Oh, if only we had a cycle counter... | |
| 36 | */ | |
| 37 | ||
| 38 | @ Delay routine | |
| 39 | ENTRY(__delay) | |
| 40 | subs r0, r0, #1 | |
| 41 | #if 0 | |
| 42 | RETINSTR(movls,pc,lr) | |
| 43 | subs r0, r0, #1 | |
| 44 | RETINSTR(movls,pc,lr) | |
| 45 | subs r0, r0, #1 | |
| 46 | RETINSTR(movls,pc,lr) | |
| 47 | subs r0, r0, #1 | |
| 48 | RETINSTR(movls,pc,lr) | |
| 49 | subs r0, r0, #1 | |
| 50 | RETINSTR(movls,pc,lr) | |
| 51 | subs r0, r0, #1 | |
| 52 | RETINSTR(movls,pc,lr) | |
| 53 | subs r0, r0, #1 | |
| 54 | RETINSTR(movls,pc,lr) | |
| 55 | subs r0, r0, #1 | |
| 56 | #endif | |
| 57 | bhi __delay | |
| 58 | RETINSTR(mov,pc,lr) |