| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * include/asm-v850/delay.h -- Delay routines, using a pre-computed |
| 3 | * "loops_per_second" value |
| 4 | * |
| 5 | * Copyright (C) 2001,03 NEC Corporation |
| 6 | * Copyright (C) 2001,03 Miles Bader <miles@gnu.org> |
| 7 | * Copyright (C) 1994 Hamish Macdonald |
| 8 | * |
| 9 | * This file is subject to the terms and conditions of the GNU General |
| 10 | * Public License. See the file COPYING in the main directory of this |
| 11 | * archive for more details. |
| 12 | */ |
| 13 | |
| 14 | #ifndef __V850_DELAY_H__ |
| 15 | #define __V850_DELAY_H__ |
| 16 | |
| 17 | #include <asm/param.h> |
| 18 | |
| 19 | extern __inline__ void __delay(unsigned long loops) |
| 20 | { |
| 21 | if (loops) |
| 22 | __asm__ __volatile__ ("1: add -1, %0; bnz 1b" |
| 23 | : "=r" (loops) : "0" (loops)); |
| 24 | } |
| 25 | |
| 26 | /* |
| 27 | * Use only for very small delays ( < 1 msec). Should probably use a |
| 28 | * lookup table, really, as the multiplications take much too long with |
| 29 | * short delays. This is a "reasonable" implementation, though (and the |
| 30 | * first constant multiplications gets optimized away if the delay is |
| 31 | * a constant) |
| 32 | */ |
| 33 | |
| 34 | extern unsigned long loops_per_jiffy; |
| 35 | |
| 36 | extern __inline__ void udelay(unsigned long usecs) |
| 37 | { |
| 38 | register unsigned long full_loops, part_loops; |
| 39 | |
| 40 | full_loops = ((usecs * HZ) / 1000000) * loops_per_jiffy; |
| 41 | usecs %= (1000000 / HZ); |
| 42 | part_loops = (usecs * HZ * loops_per_jiffy) / 1000000; |
| 43 | |
| 44 | __delay(full_loops + part_loops); |
| 45 | } |
| 46 | |
| 47 | #endif /* __V850_DELAY_H__ */ |