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add io delay patch from h-al-9000

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@2763
This commit is contained in:
Peter Veenstra 2007-01-13 10:43:40 +00:00
parent c05b3e6810
commit 1d3b064824
1 changed files with 45 additions and 5 deletions
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50
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 1.23 2007-01-08 19:45:40 qbix79 Exp $ */
/* $Id: iohandler.cpp,v 1.24 2007-01-13 10:43:40 qbix79 Exp $ */
#include <string.h>
#include "dosbox.h"
@ -162,6 +162,34 @@ static Bits IOFaultCore(void) {
return 0;
}
/* Some code to make io operations take some virtual time. Helps certain
* games with their timing of certain operations
*/
extern Bit32s CPU_CycleMax;
#define IODELAY_READ_MICROS 1.0
#define IODELAY_WRITE_MICROS 0.75
inline void IO_USEC_read_delay() {
if(CPU_CycleMax > static_cast<Bit32s>((IODELAY_READ_MICROS*1000.0))) {
// this could be calculated whenever CPU_CycleMax changes
Bitu delaycyc = static_cast<Bitu>((CPU_CycleMax/1000)*IODELAY_READ_MICROS);
if(CPU_Cycles > delaycyc) CPU_Cycles -= delaycyc;
else CPU_Cycles = 0;
}
}
inline void IO_USEC_write_delay() {
if(CPU_CycleMax > static_cast<Bit32s>((IODELAY_WRITE_MICROS*1000.0))) {
// this could be calculated whenever CPU_CycleMax changes
Bitu delaycyc = static_cast<Bitu>((CPU_CycleMax/1000)*IODELAY_WRITE_MICROS);
if(CPU_Cycles > delaycyc) CPU_Cycles -= delaycyc;
else CPU_Cycles = 0;
}
}
void IO_WriteB(Bitu port,Bitu val) {
if (GCC_UNLIKELY(GETFLAG(VM) && (CPU_IO_Exception(port,1)))) {
LazyFlags old_lflags;
@ -192,7 +220,10 @@ void IO_WriteB(Bitu port,Bitu val) {
memcpy(&lflags,&old_lflags,sizeof(LazyFlags));
cpudecoder=old_cpudecoder;
}
else io_writehandlers[0][port](port,val,1);
else {
IO_USEC_write_delay();
io_writehandlers[0][port](port,val,1);
}
};
void IO_WriteW(Bitu port,Bitu val) {
@ -225,7 +256,10 @@ void IO_WriteW(Bitu port,Bitu val) {
memcpy(&lflags,&old_lflags,sizeof(LazyFlags));
cpudecoder=old_cpudecoder;
}
else io_writehandlers[1][port](port,val,2);
else {
IO_USEC_write_delay();
io_writehandlers[1][port](port,val,2);
}
};
void IO_WriteD(Bitu port,Bitu val) {
@ -291,7 +325,10 @@ Bitu IO_ReadB(Bitu port) {
cpudecoder=old_cpudecoder;
return retval;
}
else return io_readhandlers[0][port](port,1);
else {
IO_USEC_read_delay();
return io_readhandlers[0][port](port,1);
}
};
Bitu IO_ReadW(Bitu port) {
@ -324,7 +361,10 @@ Bitu IO_ReadW(Bitu port) {
cpudecoder=old_cpudecoder;
return retval;
}
else return io_readhandlers[1][port](port,2);
else {
IO_USEC_read_delay();
return io_readhandlers[1][port](port,2);
}
};
Bitu IO_ReadD(Bitu port) {