/* $Id: delay.h,v 1.2 1999/01/04 16:09:20 ralf Exp $ * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1994 by Waldorf Electronics * Copyright (C) 1995 - 1998 by Ralf Baechle */ #ifndef _ASM_DELAY_H #define _ASM_DELAY_H #include extern __inline__ void __delay(unsigned long loops) { __asm__ __volatile__ ( ".set\tnoreorder\n" "1:\tbnez\t%0,1b\n\t" "subu\t%0,1\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, unsigned long lps) { usecs *= 0x000010c6; /* 2**32 / 1000000 */ __asm__("multu\t%0,%2\n\t" "mfhi\t%0" :"=r" (usecs) :"0" (usecs),"r" (lps)); __delay(usecs); } #ifdef CONFIG_SMP #define __udelay_val cpu_data[smp_processor_id()].udelay_val #else #define __udelay_val loops_per_sec #endif #define udelay(usecs) __udelay((usecs),__udelay_val) #endif /* _ASM_DELAY_H */