/* * Precise Delay Loops for i386 * * Copyright (C) 1993 Linus Torvalds * Copyright (C) 1997 Martin Mares * * 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 #include #ifdef __SMP__ #include #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 */ }