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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [include/] [asm-mips/] [delay.h] - Rev 1765
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#ifndef __ASM_MIPS_DELAY_H #define __ASM_MIPS_DELAY_H extern __inline__ void __delay(int loops) { __asm__ __volatile__ ( ".set\tnoreorder\n\t" ".set\tnoat\n\t" "1:\tbne\t$0,%0,1b\n\t" "subu\t%0,%0,1\n\t" ".set\tat\n\t" ".set\treorder" :"=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 *= 0x000010c6; /* 2**32 / 1000000 */ __asm__("multu\t%0,%1\n\t" "mfhi\t%0" :"=r" (usecs) :"0" (usecs),"r" (loops_per_sec)); __delay(usecs); } /* * The different variants for 32/64 bit are pure paranoia. The typical * range of numbers that appears for MIPS machines avoids overflows. */ extern __inline__ unsigned long muldiv(unsigned long a, unsigned long b, unsigned long c) { return (a*b)/c; } #endif /* __ASM_MIPS_DELAY_H */