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Start stuff with an REFT instead of IRET. Fixes CyberRace.(Beta 2)

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3260
This commit is contained in:
Peter Veenstra 2009-01-14 22:16:00 +00:00
parent 4e8f79fd9e
commit f47d48ba07
4 changed files with 33 additions and 12 deletions
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5
include/callback.h
View file

@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: callback.h,v 1.21 2007-06-12 20:22:07 c2woody Exp $ */
/* $Id: callback.h,v 1.22 2009-01-14 22:16:00 qbix79 Exp $ */
#ifndef DOSBOX_CALLBACK_H
#define DOSBOX_CALLBACK_H
@ -30,7 +30,8 @@ extern CallBack_Handler CallBack_Handlers[];
enum { CB_RETN,CB_RETF,CB_RETF8,CB_IRET,CB_IRETD,CB_IRET_STI,CB_IRET_EOI_PIC1,
CB_IRQ0,CB_IRQ1,CB_IRQ9,CB_IRQ12,CB_IRQ12_RET,CB_IRQ6_PCJR,CB_MOUSE,
CB_INT29,CB_INT16,CB_HOOKABLE,CB_TDE_IRET,CB_IPXESR,CB_IPXESR_RET };
CB_INT29,CB_INT16,CB_HOOKABLE,CB_TDE_IRET,CB_IPXESR,CB_IPXESR_RET,
CB_INT21 };
#define CB_MAX 128
#define CB_SIZE 32

14
src/cpu/callback.cpp
View file

@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: callback.cpp,v 1.37 2007-06-03 16:46:33 c2woody Exp $ */
/* $Id: callback.cpp,v 1.38 2009-01-14 22:16:00 qbix79 Exp $ */
#include <stdlib.h>
#include <string.h>
@ -403,6 +403,18 @@ Bitu CALLBACK_SetupExtra(Bitu callback, Bitu type, PhysPt physAddress, bool use_
phys_writeb(physAddress+0x0d,(Bit8u)0x1f); // pop ds
phys_writeb(physAddress+0x0e,(Bit8u)0xcf); //An IRET Instruction
return 0x0f; */
case CB_INT21:
phys_writeb(physAddress+0x00,(Bit8u)0xFB); //STI
if (use_cb) {
phys_writeb(physAddress+0x01,(Bit8u)0xFE); //GRP 4
phys_writeb(physAddress+0x02,(Bit8u)0x38); //Extra Callback instruction
phys_writew(physAddress+0x03, callback); //The immediate word
physAddress+=4;
}
phys_writeb(physAddress+0x01,(Bit8u)0xCF); //An IRET Instruction
phys_writeb(physAddress+0x02,(Bit8u)0xCB); //A RETF Instruction
return (use_cb?7:3);
default:
E_Exit("CALLBACK:Setup:Illegal type %d",type);
}

11
src/dos/dos.cpp
View file

@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: dos.cpp,v 1.114 2008-12-11 09:16:31 qbix79 Exp $ */
/* $Id: dos.cpp,v 1.115 2009-01-14 22:16:00 qbix79 Exp $ */
#include <stdlib.h>
#include <string.h>
@ -1041,7 +1041,7 @@ static Bitu DOS_21Handler(void) {
break;
};
return CBRET_NONE;
};
}
static Bitu DOS_20Handler(void) {
@ -1091,8 +1091,13 @@ public:
callback[0].Install(DOS_20Handler,CB_IRET,"DOS Int 20");
callback[0].Set_RealVec(0x20);
callback[1].Install(DOS_21Handler,CB_IRET_STI,"DOS Int 21");
callback[1].Install(DOS_21Handler,CB_INT21,"DOS Int 21");
callback[1].Set_RealVec(0x21);
//Pseudo code for int 21
// sti
// callback
// iret
// retf <- int 21 4c jumps here to mimic a retf Cyber
callback[2].Install(DOS_25Handler,CB_RETF,"DOS Int 25");
callback[2].Set_RealVec(0x25);

15
src/dos/dos_execute.cpp
View file

@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: dos_execute.cpp,v 1.65 2008-10-05 14:44:52 qbix79 Exp $ */
/* $Id: dos_execute.cpp,v 1.66 2009-01-14 22:16:00 qbix79 Exp $ */
#include <string.h>
#include <ctype.h>
@ -457,13 +457,16 @@ bool DOS_Execute(char * name,PhysPt block_pt,Bit8u flags) {
/* Set the stack for new program */
SegSet16(ss,RealSeg(sssp));reg_sp=RealOff(sssp);
/* Add some flags and CS:IP on the stack for the IRET */
reg_sp-=6;
reg_sp-=4;
mem_writew(SegPhys(ss)+reg_sp+0,RealOff(csip));
mem_writew(SegPhys(ss)+reg_sp+2,RealSeg(csip));
/* DOS starts programs with a RETF, so our IRET
should not modify critical flags (IOPL in v86 mode);
interrupt flag is set explicitly, test flags cleared */
mem_writew(SegPhys(ss)+reg_sp+4,(reg_flags&(~FMASK_TEST))|FLAG_IF);
/* Old info, we now jump to a RETF:
* DOS starts programs with a RETF, so our IRET
* should not modify critical flags (IOPL in v86 mode);
* interrupt flag is set explicitly, test flags cleared */
reg_flags=(reg_flags&(~FMASK_TEST))|FLAG_IF;
//Jump to retf so that we only need to store cs:ip on the stack
reg_ip++;
/* Setup the rest of the registers */
reg_ax=reg_bx=0;reg_cx=0xff;
reg_dx=pspseg;