mirror of
https://github.com/ZDoom/qzdoom-gpl.git
synced 2024-12-02 08:22:25 +00:00
36 lines
1.1 KiB
C
36 lines
1.1 KiB
C
|
#ifndef INTERNAL_MULSC_H
|
||
|
|
#define INTERNAL_MULSC_H
|
||
|
|
|
||
|
|
#if !defined(_MSC_VER) || !defined(_M_IX86) || _MSC_VER >= 1800
|
||
|
|
//#define MULSC(a, b) ((int)((LONG_LONG)(a) * (b) >> 16))
|
||
|
|
//#define MULSC(a, b) ((a) * ((b) >> 2) >> 14)
|
||
|
|
#define MULSCV(a, b) ((int)((LONG_LONG)(a) * (b) >> 32))
|
||
|
|
#define MULSCA(a, b) ((int)((LONG_LONG)((a) << 4) * (b) >> 32))
|
||
|
|
#define MULSC(a, b) ((int)((LONG_LONG)((a) << 4) * ((b) << 12) >> 32))
|
||
|
|
#define MULSC16(a, b) ((int)((LONG_LONG)((a) << 12) * ((b) << 12) >> 32))
|
||
|
|
#else
|
||
|
|
/* VC++ calls __allmull and __allshr for the above math. I don't know why.
|
||
|
|
* [Need to check if this still applies to recent versions of the compiler.] */
|
||
|
|
static __forceinline unsigned long long MULLL(int a, int b)
|
||
|
|
{
|
||
|
|
__asm mov eax,a
|
||
|
|
__asm imul b
|
||
|
|
}
|
||
|
|
static __forceinline int MULSCV (int a, int b)
|
||
|
|
{
|
||
|
|
#ifndef _DEBUG
|
||
|
|
union { unsigned long long q; struct { int l, h; }; } val;
|
||
|
|
val.q = MULLL(a,b);
|
||
|
|
return val.h;
|
||
|
|
#else
|
||
|
|
__asm mov eax,a
|
||
|
|
__asm imul b
|
||
|
|
__asm mov eax,edx
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
#define MULSCA(a, b) MULSCV((a) << 4, b)
|
||
|
|
#define MULSC(a, b) MULSCV((a) << 4, (b) << 12)
|
||
|
|
#define MULSC16(a, b) MULSCV((a) << 12, (b) << 12)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#endif /* INTERNAL_MULSC_H */
|