?? delay.c
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/* * Precise Delay Loops for x86-64 * * Copyright (C) 1993 Linus Torvalds * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> * * The __delay function must _NOT_ be inlined as its execution time * depends wildly on alignment on many x86 processors. */#include <linux/config.h>#include <linux/sched.h>#include <linux/delay.h>#include <asm/delay.h>#include <asm/msr.h>#ifdef CONFIG_SMP#include <asm/smp.h>#endifint read_current_timer(unsigned long *timer_value){ rdtscll(*timer_value); return 0;}void __delay(unsigned long loops){ unsigned bclock, now; rdtscl(bclock); do { rep_nop(); rdtscl(now); } while((now-bclock) < loops);}inline void __const_udelay(unsigned long xloops){ __delay(((xloops * cpu_data[raw_smp_processor_id()].loops_per_jiffy) >> 32) * HZ);}void __udelay(unsigned long usecs){ __const_udelay(usecs * 0x000010c6); /* 2**32 / 1000000 */}void __ndelay(unsigned long nsecs){ __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */}
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