switch-coreboot/include/cpu/generic/x86/div64.h
Stefan Reinauer c275218a89 Add a first bit of a framework. Builds the following parts, in
accordance to the newboot document:

* reset vector (16 bytes)
* vpd (240bytes)
* boot block (8k - 256b)
* lar archive (256-8 k)

The boot block is kind of simple, still. It enables pmode, car, and
starts looking for an initram module in the lar archive.

Note: This doesnt do much at the moment,
as gas seems to produce buggy code in init.S.

Take this as a suggestion of how it might work and please provide
patches fixing it and bringing it into shape.

Signed-off-by: Stefan Reinauer <stepan@coresystems.de>
Acked-by: Ronald G. Minnich <rminnich@gmail.com>



git-svn-id: svn://coreboot.org/repository/LinuxBIOSv3@62 f3766cd6-281f-0410-b1cd-43a5c92072e9
2007-01-29 22:09:50 +00:00

48 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)
{
long dum2;
__asm__("divl %2":"=a"(dum2), "=d"(*rem)
: "rm"(div), "A"(divs));
return dum2;
}
#endif