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added basic BCD counting

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@1695
This commit is contained in:
Peter Veenstra 2004-03-03 12:37:12 +00:00
parent 2c8d03d6b6
commit 11b3ee2999
1 changed files with 49 additions and 13 deletions
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62
src/hardware/timer.cpp
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@ -16,7 +16,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* $Id: timer.cpp,v 1.21 2004-02-07 18:34:03 harekiet Exp $ */
/* $Id: timer.cpp,v 1.22 2004-03-03 12:37:12 qbix79 Exp $ */
#include "dosbox.h"
#include "inout.h"
@ -27,6 +27,17 @@
#include "mixer.h"
#include "timer.h"
static INLINE void BIN2BCD(Bit16u& val) {
Bit16u temp=val%10 + (((val/10)%10)<<4)+ (((val/100)%10)<<8) + (((val/1000)%10)<<12);
val=temp;
}
static INLINE void BCD2BIN(Bit16u& val) {
Bit16u temp= (val&0x0f) +((val>>4)&0x0f) *10 +((val>>8)&0x0f) *100 +((val>>12)&0x0f) *1000;
val=temp;
}
struct PIT_Block {
Bit8u mode; /* Current Counter Mode */
@ -36,9 +47,11 @@ struct PIT_Block {
Bit8u latch_mode;
Bit8u read_state;
Bit16s read_latch;
Bit16u read_latch;
Bit8u write_state;
Bit16u write_latch;
bool bcd;
bool go_read_latch;
};
static PIT_Block pit[3];
@ -51,6 +64,7 @@ static void PIT0_Event(Bitu val) {
static void counter_latch(Bitu counter) {
/* Fill the read_latch of the selected counter with current count */
PIT_Block * p=&pit[counter];
p->go_read_latch=false;
Bit64s micro=PIC_MicroCount()-p->start;
@ -91,6 +105,8 @@ static void counter_latch(Bitu counter) {
static void write_latch(Bit32u port,Bit8u val) {
Bitu counter=port-0x40;
PIT_Block * p=&pit[counter];
if(p->bcd == true) BIN2BCD(p->write_latch);
switch (p->write_state) {
case 0:
p->write_latch = p->write_latch | ((val & 0xff) << 8);
@ -106,9 +122,14 @@ static void write_latch(Bit32u port,Bit8u val) {
case 2:
p->write_latch = (val & 0xff) << 8;
break;
}
}
if(p->bcd==true) BCD2BIN(p->write_latch);
if (p->write_state != 0) {
if (p->write_latch == 0) p->cntr = 0x10000;
if (p->write_latch == 0) {
if(p->bcd == false) {p->cntr = 0x10000;} else {p->cntr=9999;}
}
else p->cntr = p->write_latch;
p->start=PIC_MicroCount();
p->micro=(Bits)(1000000/((float)PIT_TICK_RATE/(float)p->cntr));
@ -130,14 +151,16 @@ static void write_latch(Bit32u port,Bit8u val) {
static Bit8u read_latch(Bit32u port) {
Bit32u counter=port-0x40;
if (pit[counter].read_latch == -1)
if (pit[counter].go_read_latch == true)
counter_latch(counter);
Bit8u ret;
if( pit[counter].bcd == true) BIN2BCD(pit[counter].read_latch);
switch (pit[counter].read_state) {
case 0: /* read MSB & return to state 3 */
ret=(pit[counter].read_latch >> 8) & 0xff;
pit[counter].read_state = 3;
pit[counter].read_latch = -1;
pit[counter].go_read_latch = true;
break;
case 3: /* read LSB followed by MSB */
ret = (pit[counter].read_latch & 0xff);
@ -147,17 +170,19 @@ static Bit8u read_latch(Bit32u port) {
break;
case 1: /* read LSB */
ret = (pit[counter].read_latch & 0xff);
pit[counter].read_latch = -1;
pit[counter].go_read_latch = true;
break;
case 2: /* read MSB */
ret = (pit[counter].read_latch >> 8) & 0xff;
pit[counter].read_latch = -1;
pit[counter].go_read_latch = true;
break;
default:
ret=0;
E_Exit("Timer.cpp: error in readlatch");
break;
}
}
if( pit[counter].bcd == true) BCD2BIN(pit[counter].read_latch);
return ret;
}
@ -167,7 +192,10 @@ static void write_p43(Bit32u port,Bit8u val) {
case 0:
case 1:
case 2:
if (val & 1) E_Exit("PIT:Timer %d set to unsupported bcd mode",latch);
pit[latch].bcd = (val&1)>0;
if (val & 1) if(pit[latch].cntr>=9999) pit[latch].cntr=9999;
if ((val & 0x30) == 0) {
/* Counter latch command */
counter_latch(latch);
@ -201,16 +229,24 @@ void TIMER_Init(Section* sect) {
pit[0].cntr=0x10000;
pit[0].write_state = 3;
pit[0].read_state = 3;
pit[0].read_latch=-1;
pit[0].read_latch=0;
pit[0].write_latch=0;
pit[0].mode=3;
pit[0].bcd = false;
pit[0].go_read_latch = true;
pit[1].bcd = false;
pit[1].go_read_latch = true;
pit[1].mode = 3;
pit[1].write_state = 3;
pit[0].micro=(Bits)(1000000/((float)PIT_TICK_RATE/(float)pit[0].cntr));
pit[2].micro=100;
pit[2].read_latch=-1; /* MadTv1 */
pit[2].read_latch=0; /* MadTv1 */
pit[2].write_state = 3; /* Chuck Yeager */
pit[2].mode=3;
pit[2].bcd=false;
pit[2].go_read_latch=true;
PIC_AddEvent(PIT0_Event,pit[0].micro);
}