diff options
Diffstat (limited to 'linux/src/include/asm-i386/delay.h')
-rw-r--r-- | linux/src/include/asm-i386/delay.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/linux/src/include/asm-i386/delay.h b/linux/src/include/asm-i386/delay.h new file mode 100644 index 00000000..2f4a41b9 --- /dev/null +++ b/linux/src/include/asm-i386/delay.h @@ -0,0 +1,63 @@ +#ifndef _I386_DELAY_H +#define _I386_DELAY_H + +/* + * Copyright (C) 1993 Linus Torvalds + * + * Delay routines, using a pre-computed "loops_per_second" value. + */ + +#include <linux/linkage.h> + +#ifdef __SMP__ +#include <asm/smp.h> +#endif + +extern void __do_delay(void); /* Special register call calling convention */ + +extern __inline__ void __delay(int loops) +{ + __asm__ __volatile__( + "call " SYMBOL_NAME_STR(__do_delay) + :/* no outputs */ + :"a" (loops) + :"ax"); +} + +/* + * 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 *= 0x000010c6; /* 2**32 / 1000000 */ + __asm__("mull %0" + :"=d" (usecs) +#ifdef __SMP__ + :"a" (usecs),"0" (cpu_data[smp_processor_id()].udelay_val) +#else + :"a" (usecs),"0" (loops_per_sec) +#endif + :"ax"); + + __delay(usecs); +} + +extern __inline__ unsigned long muldiv(unsigned long a, unsigned long b, unsigned long c) +{ + __asm__("mull %1 ; divl %2" + :"=a" (a) + :"d" (b), + "r" (c), + "0" (a) + :"dx"); + return a; +} + +#endif /* defined(_I386_DELAY_H) */ |