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move callbacks into read-only memory (Pinball/Adventure construction kit booters)

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@2612
This commit is contained in:
Sebastian Strohhäcker 2006-04-22 15:25:45 +00:00
parent 1d11c37e23
commit 1d89346c16
8 changed files with 131 additions and 140 deletions
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19
src/ints/xms.cpp
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@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: xms.cpp,v 1.40 2006-04-14 13:53:58 qbix79 Exp $ */
/* $Id: xms.cpp,v 1.41 2006-04-22 15:25:45 c2woody Exp $ */
#include <stdlib.h>
#include <string.h>
@ -413,20 +413,9 @@ public:
Bitu i;
BIOS_ZeroExtendedSize(true);
DOS_AddMultiplexHandler(multiplex_xms);
callbackhandler.Install(&XMS_Handler,CB_RETF, "XMS Handler");
xms_callback=callbackhandler.Get_RealPointer();
Bit16u call_xms=callbackhandler.Get_callback();
/* Override the callback with one that can be hooked */
phys_writeb(CB_BASE+(call_xms<<4)+0,(Bit8u)0xeb); //jump near
phys_writeb(CB_BASE+(call_xms<<4)+1,(Bit8u)0x03); //offset
phys_writeb(CB_BASE+(call_xms<<4)+2,(Bit8u)0x90); //NOP
phys_writeb(CB_BASE+(call_xms<<4)+3,(Bit8u)0x90); //NOP
phys_writeb(CB_BASE+(call_xms<<4)+4,(Bit8u)0x90); //NOP
phys_writeb(CB_BASE+(call_xms<<4)+5,(Bit8u)0xFE); //GRP 4
phys_writeb(CB_BASE+(call_xms<<4)+6,(Bit8u)0x38); //Extra Callback instruction
phys_writew(CB_BASE+(call_xms<<4)+7,call_xms); //The immediate word
phys_writeb(CB_BASE+(call_xms<<4)+9,(Bit8u)0xCB); //A RETF Instruction
/* place hookable callback in writable memory area */
xms_callback=RealMake(DOS_GetMemory(0x1),0);
callbackhandler.Install(&XMS_Handler,CB_HOOKABLE,Real2Phys(xms_callback),"XMS Handler");
for (i=0;i<XMS_HANDLES;i++) {
xms_handles[i].free=true;