Cxbx-Reloaded/Include/Win32/CxbxKrnl/EmuFS.h

142 lines
4.8 KiB
C

// ******************************************************************
// *
// * .,-::::: .,:: .::::::::. .,:: .:
// * ,;;;'````' `;;;, .,;; ;;;'';;' `;;;, .,;;
// * [[[ '[[,,[[' [[[__[[\. '[[,,[['
// * $$$ Y$$$P $$""""Y$$ Y$$$P
// * `88bo,__,o, oP"``"Yo, _88o,,od8P oP"``"Yo,
// * "YUMMMMMP",m" "Mm,""YUMMMP" ,m" "Mm,
// *
// * Cxbx->Win32->CxbxKrnl->EmuFS.h
// *
// * This file is part of the Cxbx project.
// *
// * Cxbx and Cxbe are free software; you can redistribute them
// * and/or modify them under the terms of the GNU General Public
// * License as published by the Free Software Foundation; either
// * version 2 of the license, or (at your option) 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 recieved a copy of the GNU General Public License
// * along with this program; see the file COPYING.
// * If not, write to the Free Software Foundation, Inc.,
// * 59 Temple Place - Suite 330, Bostom, MA 02111-1307, USA.
// *
// * (c) 2002-2003 Aaron Robinson <caustik@caustik.com>
// *
// * All rights reserved
// *
// ******************************************************************
#ifndef EMUFS_H
#define EMUFS_H
#include "Xbe.h"
// word @ FS:[0x14] := wSwapFS
// byte @ FS:[0x16] := bIsXboxFS
#undef FIELD_OFFSET // prevent macro redefinition warnings
#include <windows.h>
// ******************************************************************
// * func: EmuGenerateFS
// ******************************************************************
extern void EmuGenerateFS(Xbe::TLS *pTLS, void *pTLSData);
// ******************************************************************
// * func: EmuCleanupFS
// ******************************************************************
extern void EmuCleanupFS();
// ******************************************************************
// * func: EmuInitFS
// ******************************************************************
extern void EmuInitFS();
// ******************************************************************
// * func: EmuIsXboxFS
// ******************************************************************
// *
// * This function will return true if the current FS register is
// * the Xbox emulation variety. Alternatively, false means the
// * Win2k/XP FS register is currently loaded.
// *
// ******************************************************************
static inline bool EmuIsXboxFS()
{
unsigned char chk;
__asm
{
mov ah, fs:[0x16]
mov chk, ah
}
return (chk == 1);
}
// ******************************************************************
// * data: EmuAutoSleepRate
// ******************************************************************
// *
// * Xbox is a single process system, and because of this fact, demos
// * and games are likely to suffer from Xbox-Never-Sleeps syndrome.
// *
// * Basically, there are situations where the Xbe will have no
// * reason to bother yielding to other threads. One solution to this
// * problem is to keep track of the number of function intercepts,
// * and every so often, force a sleep. This is the rate at which
// * those forced sleeps occur.
// *
// ******************************************************************
extern uint32 EmuAutoSleepRate;
// ******************************************************************
// * func: EmuSwapFS
// ******************************************************************
// *
// * This function is used to swap between the native Win2k/XP FS:
// * structure, and the Emu FS: structure. Before running Windows
// * code, you *must* swap over to Win2k/XP FS. Similarly, before
// * running Xbox code, you *must* swap back over to Emu FS.
// *
// ******************************************************************
static inline void EmuSwapFS()
{
// Note that this is only the *approximate* interception count,
// because not all interceptions swap the FS register, and some
// non-interception code uses it
static uint32 dwInterceptionCount = 0;
__asm
{
mov ax, fs:[0x14]
mov fs, ax
}
// ******************************************************************
// * Every "N" interceptions, perform various periodic services
// ******************************************************************
if(dwInterceptionCount++ == EmuAutoSleepRate)
{
// If we're in the Xbox FS, wait until the next swap
if(EmuIsXboxFS())
{
dwInterceptionCount--;
return;
}
// Yield!
Sleep(1);
// Back to Zero!
dwInterceptionCount = 0;
}
}
#endif