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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [include/] [asm-alpha/] [delay.h] - Rev 1777
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#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); } /* * 64-bit integers means we don't have to worry about overflow as * on some other architectures.. */ extern __inline__ unsigned long muldiv(unsigned long a, unsigned long b, unsigned long c) { return (a*b)/c; } #endif /* defined(__ALPHA_DELAY_H) */
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