projects / linux-2.6-block.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> | |
| d0a533b1 | 12 | #include <asm/delay.h> |
| 215e362d | 13 | |
| 1da177e4 LT |
14 | .text |
| 15 | ||
| 8adbb371 | 16 | .LC0: .word loops_per_jiffy |
| d0a533b1 | 17 | .LC1: .word UDELAY_MULT |
| 1da177e4 LT |
18 | |
| 19 | /* | |
| 207b1150 NP |
20 | * loops = r0 * HZ * loops_per_jiffy / 1000000 |
| 21 | * | |
| 6d4518d7 | 22 | * r0 <= 2000 |
| 6d4518d7 | 23 | * HZ <= 1000 |
| 1da177e4 | 24 | */ |
| 6d4518d7 | 25 | |
| d0a533b1 | 26 | ENTRY(__loop_udelay) |
| 6d4518d7 | 27 | ldr r2, .LC1 |
| 207b1150 NP |
28 | mul r0, r2, r0 @ r0 = delay_us * UDELAY_MULT |
| 29 | ENTRY(__loop_const_udelay) @ 0 <= r0 <= 0xfffffaf0 | |
| 8adbb371 | 30 | ldr r2, .LC0 |
| 215e362d | 31 | ldr r2, [r2] |
| 207b1150 NP |
32 | umull r1, r0, r2, r0 @ r0-r1 = r0 * loops_per_jiffy |
| 33 | adds r1, r1, #0xffffffff @ rounding up ... | |
| 34 | adcs r0, r0, r0 @ and right shift by 31 | |
| 6ebbf2ce | 35 | reteq lr |
| 1da177e4 | 36 | |
| 11d4bb1b | 37 | .align 3 |
| 1da177e4 LT |
38 | |
| 39 | @ Delay routine | |
| d0a533b1 | 40 | ENTRY(__loop_delay) |
| 1da177e4 LT |
41 | subs r0, r0, #1 |
| 42 | #if 0 | |
| 6ebbf2ce | 43 | retls lr |
| 1da177e4 | 44 | subs r0, r0, #1 |
| 6ebbf2ce | 45 | retls lr |
| 1da177e4 | 46 | subs r0, r0, #1 |
| 6ebbf2ce | 47 | retls lr |
| 1da177e4 | 48 | subs r0, r0, #1 |
| 6ebbf2ce | 49 | retls lr |
| 1da177e4 | 50 | subs r0, r0, #1 |
| 6ebbf2ce | 51 | retls lr |
| 1da177e4 | 52 | subs r0, r0, #1 |
| 6ebbf2ce | 53 | retls lr |
| 1da177e4 | 54 | subs r0, r0, #1 |
| 6ebbf2ce | 55 | retls lr |
| 1da177e4 LT |
56 | subs r0, r0, #1 |
| 57 | #endif | |
| d0a533b1 | 58 | bhi __loop_delay |
| 6ebbf2ce | 59 | ret lr |
| d0a533b1 WD |
60 | ENDPROC(__loop_udelay) |
| 61 | ENDPROC(__loop_const_udelay) | |
| 62 | ENDPROC(__loop_delay) |