diff --git a/include/callback.h b/include/callback.h
index ca919ab6..291233b3 100644
--- a/include/callback.h
+++ b/include/callback.h
@@ -16,6 +16,8 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+/* $Id: callback.h,v 1.10 2004-12-28 16:13:26 qbix79 Exp $ */
+
 #ifndef __CALLBACK_H
 #define __CALLBACK_H
 
@@ -55,5 +57,8 @@ bool CALLBACK_Free(Bitu callback);
 
 void CALLBACK_SCF(bool val);
 void CALLBACK_SZF(bool val);
+
+extern Bitu call_priv_io;
+
 #endif
 
diff --git a/include/inout.h b/include/inout.h
index bb83949b..54aaf6b8 100644
--- a/include/inout.h
+++ b/include/inout.h
@@ -16,6 +16,11 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+/* $Id: inout.h,v 1.6 2004-12-28 16:13:26 qbix79 Exp $ */
+
+#ifndef __INOUT_H
+#define __INOUT_H
+
 #define IO_MAX (64*1024+3)
 
 #define IO_MB	0x1
@@ -35,25 +40,13 @@ void IO_RegisterWriteHandler(Bitu port,IO_WriteHandler * handler,Bitu mask,Bitu
 void IO_FreeReadHandler(Bitu port,Bitu mask,Bitu range=0);
 void IO_FreeWriteHandler(Bitu port,Bitu mask,Bitu range=0);
 
-INLINE void IO_WriteB(Bitu port,Bitu val) {
-	io_writehandlers[0][port](port,val,1);
-};
-INLINE void IO_WriteW(Bitu port,Bitu val) {
-	io_writehandlers[1][port](port,val,2);
-};
-INLINE void IO_WriteD(Bitu port,Bitu val) {
-	io_writehandlers[2][port](port,val,4);
-};
+void IO_WriteB(Bitu port,Bitu val);
+void IO_WriteW(Bitu port,Bitu val);
+void IO_WriteD(Bitu port,Bitu val);
 
-INLINE Bitu IO_ReadB(Bitu port) {
-	return io_readhandlers[0][port](port,1);
-}
-INLINE Bitu IO_ReadW(Bitu port) {
-	return io_readhandlers[1][port](port,2);
-}
-INLINE Bitu IO_ReadD(Bitu port) {
-	return io_readhandlers[2][port](port,4);
-}
+Bitu IO_ReadB(Bitu port);
+Bitu IO_ReadW(Bitu port);
+Bitu IO_ReadD(Bitu port);
 
 INLINE void IO_Write(Bitu port,Bit8u val) {
 	IO_WriteB(port,val);
@@ -62,4 +55,5 @@ INLINE Bit8u IO_Read(Bitu port){
 	return IO_ReadB(port);
 }
 
+#endif
 
diff --git a/src/cpu/callback.cpp b/src/cpu/callback.cpp
index 87aaa4ac..5277031d 100644
--- a/src/cpu/callback.cpp
+++ b/src/cpu/callback.cpp
@@ -16,7 +16,7 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: callback.cpp,v 1.22 2004-08-29 11:22:37 qbix79 Exp $ */
+/* $Id: callback.cpp,v 1.23 2004-12-28 16:13:26 qbix79 Exp $ */
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -38,6 +38,7 @@ CallBack_Handler CallBack_Handlers[CB_MAX];
 char* CallBack_Description[CB_MAX];
 
 static Bitu call_stop,call_idle,call_default;
+Bitu call_priv_io;
 
 static Bitu illegal_handler(void) {
 	E_Exit("Illegal CallBack Called");
@@ -237,6 +238,24 @@ void CALLBACK_Init(Section* sec) {
 	real_writed(0,0x67*4,CALLBACK_RealPointer(call_default));
 	real_writed(0,0x5c*4,CALLBACK_RealPointer(call_default)); //Network stuff
 	//real_writed(0,0xf*4,0); some games don't like it
+
+	call_priv_io=CALLBACK_Allocate();
+
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x00,(Bit8u)0xec);	// in al, dx
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x01,(Bit8u)0xcb);	// retf
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x02,(Bit8u)0xed);	// in ax, dx
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x03,(Bit8u)0xcb);	// retf
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x04,(Bit8u)0x66);	// in eax, dx
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x05,(Bit8u)0xed);
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x06,(Bit8u)0xcb);	// retf
+
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x08,(Bit8u)0xee);	// out dx, al
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x09,(Bit8u)0xcb);	// retf
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x0a,(Bit8u)0xef);	// out dx, ax
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x0b,(Bit8u)0xcb);	// retf
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x0c,(Bit8u)0x66);	// out dx, eax
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x0d,(Bit8u)0xef);
+	phys_writeb(CB_BASE+(call_priv_io<<4)+0x0e,(Bit8u)0xcb);	// retf
 }
 
 
diff --git a/src/hardware/iohandler.cpp b/src/hardware/iohandler.cpp
index 904af71f..85874967 100644
--- a/src/hardware/iohandler.cpp
+++ b/src/hardware/iohandler.cpp
@@ -16,9 +16,16 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+/* $Id: iohandler.cpp,v 1.15 2004-12-28 16:13:26 qbix79 Exp $ */
+
 #include "dosbox.h"
 #include "inout.h"
 
+#include <string.h>
+#include "cpu.h"
+#include "../src/cpu/lazyflags.h"
+#include "callback.h"
+
 IO_WriteHandler * io_writehandlers[3][IO_MAX];
 IO_ReadHandler * io_readhandlers[3][IO_MAX];
 
@@ -99,10 +106,236 @@ void IO_FreeWriteHandler(Bitu port,Bitu mask,Bitu range) {
 }
 
 
+struct IOF_Entry {
+	Bitu cs;
+	Bitu eip;
+};
+
+#define IOF_QUEUESIZE 16
+struct {
+	Bitu used;
+	IOF_Entry entries[IOF_QUEUESIZE];
+} iof_queue;
+
+static Bits IOFaultCore(void) {
+	CPU_CycleLeft+=CPU_Cycles;
+	CPU_Cycles=1;
+	Bitu ret=CPU_Core_Full_Run();
+	CPU_CycleLeft+=CPU_Cycles;
+	if (ret<0) E_Exit("Got a dosbox close machine in IO-fault core?");
+	if (ret) 
+		return ret;
+	if (!iof_queue.used) E_Exit("IO-faul Core without IO-faul");
+	IOF_Entry * entry=&iof_queue.entries[iof_queue.used-1];
+	if (entry->cs == SegValue(cs) && entry->eip==reg_eip)
+		return -1;
+	return 0;
+}
+
+Bitu DEBUG_EnableDebugger();
+
+void IO_WriteB(Bitu port,Bitu val) {
+	if (GETFLAG(VM) && (CPU_IO_Exception(port,1))) {
+		LazyFlags old_lflags;
+		memcpy(&old_lflags,&lflags,sizeof(LazyFlags));
+		CPU_Decoder * old_cpudecoder;
+		old_cpudecoder=cpudecoder;
+		cpudecoder=&IOFaultCore;
+		IOF_Entry * entry=&iof_queue.entries[iof_queue.used++];
+		entry->cs=SegValue(cs);
+		entry->eip=reg_eip;
+		CPU_Push16(SegValue(cs));
+		CPU_Push16(reg_ip);
+		Bit8u old_al = reg_al;
+		Bit16u old_dx = reg_dx;
+		reg_al = val;
+		reg_dx = port;
+		RealPt icb = CALLBACK_RealPointer(call_priv_io);
+		SegSet16(cs,RealSeg(icb));
+		reg_eip = RealOff(icb)+0x08;
+		FillFlags();
+		CPU_Exception(cpu.exception.which,cpu.exception.error);
+
+		DOSBOX_RunMachine();
+		iof_queue.used--;
+
+		reg_al = old_al;
+		reg_dx = old_dx;
+		memcpy(&lflags,&old_lflags,sizeof(LazyFlags));
+		cpudecoder=old_cpudecoder;
+	}
+	else io_writehandlers[0][port](port,val,1);
+};
+
+void IO_WriteW(Bitu port,Bitu val) {
+	if (GETFLAG(VM) && (CPU_IO_Exception(port,2))) {
+		LazyFlags old_lflags;
+		memcpy(&old_lflags,&lflags,sizeof(LazyFlags));
+		CPU_Decoder * old_cpudecoder;
+		old_cpudecoder=cpudecoder;
+		cpudecoder=&IOFaultCore;
+		IOF_Entry * entry=&iof_queue.entries[iof_queue.used++];
+		entry->cs=SegValue(cs);
+		entry->eip=reg_eip;
+		CPU_Push16(SegValue(cs));
+		CPU_Push16(reg_ip);
+		Bit16u old_ax = reg_ax;
+		Bit16u old_dx = reg_dx;
+		reg_al = val;
+		reg_dx = port;
+		RealPt icb = CALLBACK_RealPointer(call_priv_io);
+		SegSet16(cs,RealSeg(icb));
+		reg_eip = RealOff(icb)+0x0a;
+		FillFlags();
+		CPU_Exception(cpu.exception.which,cpu.exception.error);
+
+		DOSBOX_RunMachine();
+		iof_queue.used--;
+
+		reg_ax = old_ax;
+		reg_dx = old_dx;
+		memcpy(&lflags,&old_lflags,sizeof(LazyFlags));
+		cpudecoder=old_cpudecoder;
+	}
+	else io_writehandlers[1][port](port,val,2);
+};
+
+void IO_WriteD(Bitu port,Bitu val) {
+	if (GETFLAG(VM) && (CPU_IO_Exception(port,4))) {
+		LazyFlags old_lflags;
+		memcpy(&old_lflags,&lflags,sizeof(LazyFlags));
+		CPU_Decoder * old_cpudecoder;
+		old_cpudecoder=cpudecoder;
+		cpudecoder=&IOFaultCore;
+		IOF_Entry * entry=&iof_queue.entries[iof_queue.used++];
+		entry->cs=SegValue(cs);
+		entry->eip=reg_eip;
+		CPU_Push16(SegValue(cs));
+		CPU_Push16(reg_ip);
+		Bit32u old_eax = reg_eax;
+		Bit16u old_dx = reg_dx;
+		reg_al = val;
+		reg_dx = port;
+		RealPt icb = CALLBACK_RealPointer(call_priv_io);
+		SegSet16(cs,RealSeg(icb));
+		reg_eip = RealOff(icb)+0x0c;
+		FillFlags();
+		CPU_Exception(cpu.exception.which,cpu.exception.error);
+
+		DOSBOX_RunMachine();
+		iof_queue.used--;
+
+		reg_eax = old_eax;
+		reg_dx = old_dx;
+		memcpy(&lflags,&old_lflags,sizeof(LazyFlags));
+		cpudecoder=old_cpudecoder;
+	}
+	else io_writehandlers[2][port](port,val,4);
+};
+
+Bitu IO_ReadB(Bitu port) {
+	if (GETFLAG(VM) && (CPU_IO_Exception(port,1))) {
+		LazyFlags old_lflags;
+		memcpy(&old_lflags,&lflags,sizeof(LazyFlags));
+		CPU_Decoder * old_cpudecoder;
+		old_cpudecoder=cpudecoder;
+		cpudecoder=&IOFaultCore;
+		IOF_Entry * entry=&iof_queue.entries[iof_queue.used++];
+		entry->cs=SegValue(cs);
+		entry->eip=reg_eip;
+		CPU_Push16(SegValue(cs));
+		CPU_Push16(reg_ip);
+		Bit16u old_dx = reg_dx;
+		reg_dx = port;
+		RealPt icb = CALLBACK_RealPointer(call_priv_io);
+		SegSet16(cs,RealSeg(icb));
+		reg_eip = RealOff(icb)+0x00;
+		FillFlags();
+		CPU_Exception(cpu.exception.which,cpu.exception.error);
+
+		DOSBOX_RunMachine();
+		iof_queue.used--;
+
+		Bitu retval = reg_al;
+
+		reg_dx = old_dx;		
+		memcpy(&lflags,&old_lflags,sizeof(LazyFlags));
+		cpudecoder=old_cpudecoder;
+		return retval;
+	}
+	else return io_readhandlers[0][port](port,1);
+};
+
+Bitu IO_ReadW(Bitu port) {
+	if (GETFLAG(VM) && (CPU_IO_Exception(port,2))) {
+		LazyFlags old_lflags;
+		memcpy(&old_lflags,&lflags,sizeof(LazyFlags));
+		CPU_Decoder * old_cpudecoder;
+		old_cpudecoder=cpudecoder;
+		cpudecoder=&IOFaultCore;
+		IOF_Entry * entry=&iof_queue.entries[iof_queue.used++];
+		entry->cs=SegValue(cs);
+		entry->eip=reg_eip;
+		CPU_Push16(SegValue(cs));
+		CPU_Push16(reg_ip);
+		Bit16u old_dx = reg_dx;
+		reg_dx = port;
+		RealPt icb = CALLBACK_RealPointer(call_priv_io);
+		SegSet16(cs,RealSeg(icb));
+		reg_eip = RealOff(icb)+0x02;
+		FillFlags();
+		CPU_Exception(cpu.exception.which,cpu.exception.error);
+
+		DOSBOX_RunMachine();
+		iof_queue.used--;
+
+		Bitu retval = reg_ax;
+
+		reg_dx = old_dx;		
+		memcpy(&lflags,&old_lflags,sizeof(LazyFlags));
+		cpudecoder=old_cpudecoder;
+		return retval;
+	}
+	else return io_readhandlers[1][port](port,2);
+};
+
+Bitu IO_ReadD(Bitu port) {
+	if (GETFLAG(VM) && (CPU_IO_Exception(port,4))) {
+		LazyFlags old_lflags;
+		memcpy(&old_lflags,&lflags,sizeof(LazyFlags));
+		CPU_Decoder * old_cpudecoder;
+		old_cpudecoder=cpudecoder;
+		cpudecoder=&IOFaultCore;
+		IOF_Entry * entry=&iof_queue.entries[iof_queue.used++];
+		entry->cs=SegValue(cs);
+		entry->eip=reg_eip;
+		CPU_Push16(SegValue(cs));
+		CPU_Push16(reg_ip);
+		Bit16u old_dx = reg_dx;
+		reg_dx = port;
+		RealPt icb = CALLBACK_RealPointer(call_priv_io);
+		SegSet16(cs,RealSeg(icb));
+		reg_eip = RealOff(icb)+0x04;
+		FillFlags();
+		CPU_Exception(cpu.exception.which,cpu.exception.error);
+
+		DOSBOX_RunMachine();
+		iof_queue.used--;
+
+		Bitu retval = reg_eax;
+
+		reg_dx = old_dx;		
+		memcpy(&lflags,&old_lflags,sizeof(LazyFlags));
+		cpudecoder=old_cpudecoder;
+		return retval;
+	}
+	else return io_readhandlers[2][port](port,4);
+};
+
+
 void IO_Init(Section * sect) {
+	iof_queue.used=0;
 	IO_FreeReadHandler(0,IO_MA,IO_MAX);
 	IO_FreeWriteHandler(0,IO_MA,IO_MAX);
 }
 
-
-