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Annotation of Gnu-Mach/linux/src/include/asm-i386/delay.h, revision 1.1.1.1

1.1       root        1: #ifndef _I386_DELAY_H
                      2: #define _I386_DELAY_H
                      3: 
                      4: /*
                      5:  * Copyright (C) 1993 Linus Torvalds
                      6:  *
                      7:  * Delay routines, using a pre-computed "loops_per_second" value.
                      8:  */
                      9: 
                     10: #include <linux/linkage.h>
                     11: 
                     12: #ifdef __SMP__
                     13: #include <asm/smp.h>
                     14: #endif 
                     15: 
                     16: extern void __do_delay(void);  /* Special register call calling convention */
                     17: 
                     18: extern __inline__ void __delay(int loops)
                     19: {
                     20:        __asm__ __volatile__(
                     21:                "call " SYMBOL_NAME_STR(__do_delay)
                     22:                :/* no outputs */
                     23:                :"a" (loops)
                     24:                :"ax");
                     25: }
                     26: 
                     27: /*
                     28:  * division by multiplication: you don't have to worry about
                     29:  * loss of precision.
                     30:  *
                     31:  * Use only for very small delays ( < 1 msec).  Should probably use a
                     32:  * lookup table, really, as the multiplications take much too long with
                     33:  * short delays.  This is a "reasonable" implementation, though (and the
                     34:  * first constant multiplications gets optimized away if the delay is
                     35:  * a constant)
                     36:  */
                     37: extern __inline__ void udelay(unsigned long usecs)
                     38: {
                     39:        usecs *= 0x000010c6;            /* 2**32 / 1000000 */
                     40:        __asm__("mull %0"
                     41:                :"=d" (usecs)
                     42: #ifdef __SMP__
                     43:                :"a" (usecs),"0" (cpu_data[smp_processor_id()].udelay_val)
                     44: #else
                     45:                :"a" (usecs),"0" (loops_per_sec)
                     46: #endif
                     47:                :"ax");
                     48:                
                     49:        __delay(usecs);
                     50: }
                     51: 
                     52: extern __inline__ unsigned long muldiv(unsigned long a, unsigned long b, unsigned long c)
                     53: {
                     54:        __asm__("mull %1 ; divl %2"
                     55:                :"=a" (a)
                     56:                :"d" (b),
                     57:                 "r" (c),
                     58:                 "0" (a)
                     59:                :"dx");
                     60:        return a;
                     61: }
                     62: 
                     63: #endif /* defined(_I386_DELAY_H) */

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