| #ifndef __I386_DIV64 |
| #define __I386_DIV64 |
| |
| /* |
| * 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) |
| |
| extern 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; |
| |
| } |
| #endif |
