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#pragma once
#include "types.h"
#include "util/debug.h"
/* Approximate numbers taken from various points in Linux kernel */
#define LOOPS_PER_JIFFY (1 << 12)
#define HZ 100 /* Found this in a random place in the kernel */
/* From arch/x86/lib/delay.c in Linux kernel */
/*
* Precise Delay Loops for i386
*
* Copyright (C) 1993 Linus Torvalds
* Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
* Copyright (C) 2008 Jiri Hladky <hladky _dot_ jiri _at_ gmail _dot_ com>
*
* The __delay function must _NOT_ be inlined as its execution time
* depends wildly on alignment on many x86 processors. The additional
* jump magic is needed to get the timing stable on all the CPU's
* we have to worry about.
*/
static void __delay(unsigned long loops)
{
__asm__ volatile(
" test %0,%0 \n"
" jz 3f \n"
" jmp 1f \n"
".align 16 \n"
"1: jmp 2f \n"
".align 16 \n"
"2: dec %0 \n"
" jnz 2b \n"
"3: dec %0 \n"
: /* we don't need output */
: "a"(loops));
}
static inline void __const_udelay(unsigned long xloops)
{
int d0;
xloops *= 4;
__asm__ volatile("mull %%edx"
: "=d"(xloops), "=&a"(d0)
: "1"(xloops), "0"(LOOPS_PER_JIFFY * (HZ / 4)));
__delay(++xloops);
}
static inline void __udelay(unsigned long usecs)
{
__const_udelay(usecs * 4295); /* 2**32 / 1000000 */
}
static inline void __ndelay(unsigned long nsecs)
{
__const_udelay(nsecs * 5); /* 2**32 / 1000000000 */
}
#define udelay(n) \
(__builtin_constant_p(n) ? ((n) > 20000 ? panic("Delay too large!") \
: __const_udelay((n)*4295)) \
: __udelay(n))
#define ndelay(n) \
(__builtin_constant_p(n) \
? ((n) > 20000 ? panic("Delay too large!") : __const_udelay((n)*5)) \
: __ndelay(n))
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