diff options
Diffstat (limited to 'linux/src/arch/i386/lib/delay.c')
| -rw-r--r-- | linux/src/arch/i386/lib/delay.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/linux/src/arch/i386/lib/delay.c b/linux/src/arch/i386/lib/delay.c new file mode 100644 index 0000000..b1551b2 --- /dev/null +++ b/linux/src/arch/i386/lib/delay.c @@ -0,0 +1,45 @@ +/* + * Precise Delay Loops for i386 + * + * 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. The additional + * jump magic is needed to get the timing stable on all the CPU's + * we have to worry about. + */ + +#include <linux/sched.h> +#include <linux/delay.h> + +#ifdef __SMP__ +#include <asm/smp.h> +#endif + +void __delay(unsigned long loops) +{ + int d0; + __asm__ __volatile__( + "\tjmp 1f\n" + ".align 16\n" + "1:\tjmp 2f\n" + ".align 16\n" + "2:\tdecl %0\n\tjns 2b" + :"=&a" (d0) + :"0" (loops)); +} + +inline void __const_udelay(unsigned long xloops) +{ + int d0; + __asm__("mull %0" + :"=d" (xloops), "=&a" (d0) + :"1" (xloops),"0" (loops_per_sec)); + __delay(xloops); +} + +void __udelay(unsigned long usecs) +{ + __const_udelay(usecs * 0x000010c6); /* 2**32 / 1000000 */ +} |