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- #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)
- 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;
- }
- #endif
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