diff options
Diffstat (limited to 'include/asm-x86/div64.h')
| -rw-r--r-- | include/asm-x86/div64.h | 60 |
1 files changed, 57 insertions, 3 deletions
diff --git a/include/asm-x86/div64.h b/include/asm-x86/div64.h index 8ac7da6ca284..e98d16e7a37a 100644 --- a/include/asm-x86/div64.h +++ b/include/asm-x86/div64.h @@ -1,5 +1,59 @@ +#ifndef _ASM_X86_DIV64_H +#define _ASM_X86_DIV64_H + #ifdef CONFIG_X86_32 -# include "div64_32.h" + +#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); + #else -# include "div64_64.h" -#endif +# include <asm-generic/div64.h> +#endif /* CONFIG_X86_32 */ + +#endif /* _ASM_X86_DIV64_H */ |