project64/Source/Glide64/FixedPoint.asm.cpp

87 lines
2.5 KiB
C++

/*
* Glide64 - Glide video plugin for Nintendo 64 emulators.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/****************************************************************
;
; Glide64 - Glide Plugin for Nintendo 64 emulators
; Project started on December 29th, 2001
;
; Authors:
; Dave2001, original author, founded the project in 2001, left it in 2002
; Gugaman, joined the project in 2002, left it in 2002
; Sergey 'Gonetz' Lipski, joined the project in 2002, main author since fall of 2002
; Hiroshi 'KoolSmoky' Morii, joined the project in 2007
;
;****************************************************************
;
; To modify Glide64:
; * Write your name and (optional)email, commented by your work, so I know who did it, and so that you can find which parts you modified when it comes time to send it to me.
; * Do NOT send me the whole project or file that you modified. Take out your modified code sections, and tell me where to put them. If people sent the whole thing, I would have many different versions, but no idea how to combine them all.
;
;****************************************************************/
#if defined(_MSC_VER) && !defined(_STDINT)
typedef signed __int64 int64_t;
#else
#include <stdint.h>
#endif
#ifdef _M_IX86
// (x * y) >> 16
extern "C" int __declspec(naked) imul16(int x, int y)
{
_asm {
push ebp
mov ebp,esp
mov eax, [x]
mov edx, [y]
imul edx
shrd eax,edx,16
leave
ret
}
}
//(x * y) >> 14
extern "C" int __declspec(naked) imul14(int x, int y)
{
_asm {
push ebp
mov ebp,esp
mov eax, [x]
mov edx, [y]
imul edx
shrd eax,edx,14
leave
ret
}
}
#else
DebugBreak();
#endif
int idiv16(int x, int y)
{
int64_t result;
const int64_t m = (int64_t)(x);
const int64_t n = (int64_t)(y);
result = (m << 16) / n;
return (int)(result);
}