diff options
Diffstat (limited to 'include/asm-alpha/delay.h')
-rw-r--r-- | include/asm-alpha/delay.h | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/include/asm-alpha/delay.h b/include/asm-alpha/delay.h new file mode 100644 index 000000000..87e69f657 --- /dev/null +++ b/include/asm-alpha/delay.h @@ -0,0 +1,38 @@ +#ifndef __ALPHA_DELAY_H +#define __ALPHA_DELAY_H + +extern unsigned long loops_per_sec; + +/* + * Copyright (C) 1993 Linus Torvalds + * + * Delay routines, using a pre-computed "loops_per_second" value. + */ + +extern __inline__ void __delay(unsigned long loops) +{ + __asm__ __volatile__(".align 3\n" + "1:\tsubq %0,1,%0\n\t" + "bge %0,1b": "=r" (loops) : "0" (loops)); +} + +/* + * division by multiplication: you don't have to worry about + * loss of precision. + * + * Use only for very small delays ( < 1 msec). Should probably use a + * lookup table, really, as the multiplications take much too long with + * short delays. This is a "reasonable" implementation, though (and the + * first constant multiplications gets optimized away if the delay is + * a constant) + */ +extern __inline__ void udelay(unsigned long usecs) +{ + usecs *= 0x000010c6f7a0b5edUL; /* 2**64 / 1000000 */ + __asm__("umulh %1,%2,%0" + :"=r" (usecs) + :"r" (usecs),"r" (loops_per_sec)); + __delay(usecs); +} + +#endif /* defined(__ALPHA_DELAY_H) */ |