coreboot-kgpe-d16/src/arch/i386/include/div64.h
Maciej Pijanka ea92185755 Add few missing prototypes, and remove few unused (thus lonelly) variables.
TODO
 - x86emu need (imo) some common header with prototypes at least
 - clog2, ulzma, hardwaremain prototypes added by this patch probably should 
   be moved to some header too.
 - in src/devices/device_util.c prototype is before function because seems, 
   it is used only within same file, if not it should be moved to debug
   section of prototypes in include/device/device.h

Signed-off-by: Maciej Pijanka <maciej.pijanka@gmail.com>
Acked-by: Myles Watson <mylesgw@gmail.com>


git-svn-id: svn://svn.coreboot.org/coreboot/trunk@4871 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
2009-10-27 14:29:29 +00:00

51 lines
1.2 KiB
C

#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);
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