#ifndef __I386_DIV64 #define __I386_DIV64 #include <linux/types.h> /* * do_div() is NOT a C function. It wants to return * two values (the quotient and the remainder), but * since that doesn't work very well in C, what it * does is: * * - modifies the 64-bit dividend _in_place_ * - returns the 32-bit remainder * * This ends up being the most efficient "calling * convention" on x86. */ #define do_div(n,base) ({ \ unsigned long __upper, __low, __high, __mod, __base; \ __base = (base); \ asm("":"=a" (__low), "=d" (__high):"A" (n)); \ __upper = __high; \ if (__high) { \ __upper = __high % (__base); \ __high = __high / (__base); \ } \ asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (__base), "0" (__low), "1" (__upper)); \ asm("":"=A" (n):"a" (__low),"d" (__high)); \ __mod; \ }) /* * (long)X = ((long long)divs) / (long)div * (long)rem = ((long long)divs) % (long)div * * Warning, this will do an exception if X overflows. */ #define div_long_long_rem(a,b,c) div_ll_X_l_rem(a,b,c) static inline long div_ll_X_l_rem(long long divs, long div, long *rem) { long dum2; __asm__("divl %2":"=a"(dum2), "=d"(*rem) : "rm"(div), "A"(divs)); return dum2; } extern uint64_t div64_64(uint64_t dividend, uint64_t divisor); #endif