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Workaround(partly) 16 port acces setting cycles to zero thereby invalidating one of the ports.

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@2808
This commit is contained in:
Peter Veenstra 2007-02-22 08:32:21 +00:00
parent 4f5516925d
commit 8dbee51bd3
1 changed files with 7 additions and 9 deletions
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16
src/hardware/iohandler.cpp
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@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: iohandler.cpp,v 1.25 2007-02-04 11:10:22 qbix79 Exp $ */
/* $Id: iohandler.cpp,v 1.26 2007-02-22 08:32:21 qbix79 Exp $ */
#include <string.h>
#include "dosbox.h"
@ -195,18 +195,16 @@ inline void IO_USEC_write_delay_old() {
inline void IO_USEC_read_delay() {
Bitu delaycyc = CPU_CycleMax/IODELAY_READ_MICROSk;
if(CPU_Cycles > delaycyc) {
CPU_Cycles -= delaycyc;
CPU_IODelayRemoved += delaycyc;
} else CPU_Cycles = 0;
if(GCC_UNLIKELY(CPU_Cycles < 3*delaycyc)) delaycyc = 0; //Else port acces will set cycles to 0. which might trigger problem with games which read 16 bit values
CPU_Cycles -= delaycyc;
CPU_IODelayRemoved += delaycyc;
}
inline void IO_USEC_write_delay() {
Bitu delaycyc = CPU_CycleMax/IODELAY_WRITE_MICROSk;
if(CPU_Cycles > delaycyc) {
CPU_Cycles -= delaycyc;
CPU_IODelayRemoved += delaycyc;
} else CPU_Cycles = 0;
if(GCC_UNLIKELY(CPU_Cycles < 3*delaycyc)) delaycyc=0;
CPU_Cycles -= delaycyc;
CPU_IODelayRemoved += delaycyc;
}