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TomW 2013-04-21 14:54:35 +01:00
commit 3c253c2cf8
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@ -0,0 +1,305 @@
/*IBM AT -
Write B0
Write aa55
Expects aa55 back*/
#include <string.h>
#include "ibm.h"
#include "pit.h"
#include "video.h"
#include "cpu.h"
/*B0 to 40, two writes to 43, then two reads - value does not change!*/
/*B4 to 40, two writes to 43, then two reads - value _does_ change!*/
//Tyrian writes 4300 or 17512
int displine;
int pitsec=0;
double PITCONST;
float cpuclock;
float isa_timing, bus_timing;
int firsttime=1;
void setpitclock(float clock)
{
float temp;
// printf("PIT clock %f\n",clock);
cpuclock=clock;
PITCONST=clock/1193182.0;
SPKCONST=clock/48000.0;
CGACONST=(clock/(19687500.0/11.0));
MDACONST=(clock/1813000.0);
VGACONST1=(clock/25175000.0);
VGACONST2=(clock/28322000.0);
setsbclock(clock);
SOUNDCONST=clock/200.0;
CASCONST=PITCONST*1192;
isa_timing = clock/8000000.0;
bus_timing = clock/(double)cpu_busspeed;
video_updatetiming();
// pclog("egacycles %i egacycles2 %i temp %f clock %f\n",egacycles,egacycles2,temp,clock);
GUSCONST=(clock/3125.0)/4.0;
GUSCONST2=(clock/3125.0)/4.0; //Timer 2 at different rate to 1?
video_recalctimings();
RTCCONST=clock/32768.0;
}
//#define PITCONST (8000000.0/1193000.0)
//#define PITCONST (cpuclock/1193000.0)
int pit0;
void pit_reset()
{
memset(&pit,0,sizeof(PIT));
pit.l[0]=0xFFFF; pit.c[0]=0xFFFF*PITCONST;
pit.l[1]=0xFFFF; pit.c[1]=0xFFFF*PITCONST;
pit.l[2]=0xFFFF; pit.c[2]=0xFFFF*PITCONST;
pit.m[0]=pit.m[1]=pit.m[2]=0;
pit.ctrls[0]=pit.ctrls[1]=pit.ctrls[2]=0;
pit.thit[0]=1;
spkstat=0;
}
void clearpit()
{
pit.c[0]=(pit.l[0]<<2);
}
float pit_timer0_freq()
{
// pclog("PIT timer 0 freq %04X %f %f\n",pit.l[0],(float)pit.l[0],1193182.0f/(float)pit.l[0]);
return 1193182.0f/(float)pit.l[0];
}
extern int ins;
void pit_write(uint16_t addr, uint8_t val)
{
int t;
uint8_t oldctrl=pit.ctrl;
cycles -= (int)PITCONST;
pit0=1;
// printf("Write PIT %04X %02X %04X:%08X %i %i\n",addr,val,CS,pc,ins);
switch (addr&3)
{
case 3: /*CTRL*/
if ((val&0xC0)==0xC0)
{
if (!(val&0x20))
{
if (val&2) pit.rl[0]=pit.c[0]/PITCONST;
if (val&4) pit.rl[1]=pit.c[1]/PITCONST;
if (val&8) pit.rl[2]=pit.c[2]/PITCONST;
}
return;
}
pit.ctrls[val>>6]=pit.ctrl=val;
if ((val>>7)==3)
{
printf("Bad PIT reg select\n");
return;
// dumpregs();
// exit(-1);
}
// printf("CTRL write %02X\n",val);
if (!(pit.ctrl&0x30))
{
pit.rl[val>>6]=pit.c[val>>6]/PITCONST;
if (pit.c[val>>6]<0) pit.rl[val>>6]=0;
// pclog("Timer latch %f %04X %04X\n",pit.c[0],pit.rl[0],pit.l[0]);
pit.ctrl|=0x30;
pit.rereadlatch[val>>6]=0;
pit.rm[val>>6]=3;
}
else
{
pit.rm[val>>6]=pit.wm[val>>6]=(pit.ctrl>>4)&3;
pit.m[val>>6]=(val>>1)&7;
if (pit.m[val>>6]>5)
pit.m[val>>6]&=3;
if (!(pit.rm[val>>6]))
{
pit.rm[val>>6]=3;
pit.rl[val>>6]=pit.c[val>>6]/PITCONST;
}
pit.rereadlatch[val>>6]=1;
if ((val>>6)==2) ppispeakon=speakon=(pit.m[2]==0)?0:1;
// pclog("ppispeakon %i\n",ppispeakon);
}
pit.wp=0;
pit.thit[pit.ctrl>>6]=0;
break;
case 0: case 1: case 2: /*Timers*/
t=addr&3;
// if (t==2) ppispeakon=speakon=0;
// pclog("Write timer %02X %i\n",pit.ctrls[t],pit.wm[t]);
switch (pit.wm[t])
{
case 1:
pit.l[t]=val;
pit.thit[t]=0;
pit.c[t]=pit.l[t]*PITCONST;
picintc(1);
break;
case 2:
pit.l[t]=(val<<8);
pit.thit[t]=0;
pit.c[t]=pit.l[t]*PITCONST;
picintc(1);
break;
case 0:
pit.l[t]&=0xFF;
pit.l[t]|=(val<<8);
pit.c[t]=pit.l[t]*PITCONST;
// pclog("%04X %f\n",pit.l[t],pit.c[t]);
pit.thit[t]=0;
pit.wm[t]=3;
picintc(1);
break;
case 3:
pit.l[t]&=0xFF00;
pit.l[t]|=val;
pit.wm[t]=0;
break;
/*
if (pit.wp)
{
pit.l[t]&=0xFF;
pit.l[t]|=(val<<8);
pit.c[t]=pit.l[t]*PITCONST;
pit.thit[t]=0;
}
else
{
pit.l[t]&=0xFF00;
pit.l[t]|=val;
}
pit.rl[t]=pit.l[t];
pit.wp^=1;
pit.rm[t]=3;
pit.rereadlatch[t]=1;
break;*/
}
speakval=(((float)pit.l[2]/(float)pit.l[0])*0x4000)-0x2000;
// printf("Speakval now %i\n",speakval);
// if (speakval>0x2000)
// printf("Speaker overflow - %i %i %04X %04X\n",pit.l[0],pit.l[2],pit.l[0],pit.l[2]);
if (speakval>0x2000) speakval=0x2000;
if (!pit.l[t])
{
pit.l[t]|=0x10000;
pit.c[t]=pit.l[t]*PITCONST;
}
break;
}
}
uint8_t pit_read(uint16_t addr)
{
uint8_t temp;
cycles -= (int)PITCONST;
// printf("Read PIT %04X ",addr);
switch (addr&3)
{
case 0: case 1: case 2: /*Timers*/
if (pit.rereadlatch[addr&3])// || !(pit.ctrls[addr&3]&0x30))
{
pit.rereadlatch[addr&3]=0;
pit.rl[addr&3]=pit.c[addr&3]/PITCONST;
if ((pit.c[addr&3]/PITCONST)>65536) pit.rl[addr&3]=0xFFFF;
}
switch (pit.rm[addr&3])
{
case 0:
temp=pit.rl[addr&3]>>8;
pit.rm[addr&3]=3;
pit.rereadlatch[addr&3]=1;
break;
case 1:
temp=(pit.rl[addr&3])&0xFF;
pit.rereadlatch[addr&3]=1;
break;
case 2:
temp=(pit.rl[addr&3])>>8;
pit.rereadlatch[addr&3]=1;
break;
case 3:
temp=(pit.rl[addr&3])&0xFF;
if (pit.m[addr&3]&0x80) pit.m[addr&3]&=7;
else pit.rm[addr&3]=0;
break;
}
break;
case 3: /*Control*/
temp=pit.ctrl;
}
// printf("%02X %i %i %04X:%04X\n",temp,pit.rm[addr&3],pit.wp,cs>>4,pc);
return temp;
}
void pit_poll()
{
pitsec++;
// printf("Poll pit %f %f %f\n",pit.c[0],pit.c[1],pit.c[2]);
if (pit.c[0]<1)
{
if (pit.m[0]==0 || pit.m[0]==4)
{
// pit.c[0]&=0xFFFF;
pit.c[0]+=(0x10000*PITCONST);
}
else if (pit.m[0]==3 || pit.m[0]==2)
{
if (pit.l[0]) pit.c[0]+=((float)(pit.l[0]*PITCONST));
else pit.c[0]+=((float)(0x10000*PITCONST));
}
// pit.c[0]+=(pit.l[0]*PITCONST);
// printf("PIT over! %f %i\n",pit.c[0],pit.m[0]);
if (!pit.thit[0] && (pit.l[0]>0x14))
{
// printf("PIT int!\n");
/// printf("%05X %05X %02X\n",pit.c[0],pit.l[0],pit.ctrls[0]);
picint(1);
}
if (!pit.m[0] || pit.m[0]==4) pit.thit[0]=1;
// if ((pit.ctrls[0]&0xE)==2) pit.thit[0]=1;
pit0=0;
pitcount++;
}
if (pit.c[1]<1)
{
// if (output) printf("PIT1 over %02X\n",pit.m[1]);
if (pit.m[1]==0 || pit.m[1]==4)
{
pit.c[1]=0xFFFFFF*PITCONST;
}
else
{
pit.c[1]+=(pit.l[1]*PITCONST);
}
// if (output) pclog("%f %04X %02X\n",pit.c[1],pit.l[1],pit.ctrls[1]);
// printf("DMA0!\n");
readdma0();
}
if (pit.c[2]<1)
{
// printf("PIT 2 over %i\n",pit.m[2]);
if (!pit.m[2] || pit.m[2]==4)
{
pit.c[2]+=(0x10000*PITCONST);
speakon^=1;
ppispeakon^=1;
}
else
{
pit.c[2]+=((pit.l[2]*PITCONST)/2);
if (pit.l[2]>0x30) /*Some games use very high frequencies as 'speaker off'. This stops them from generating noise*/
speakon^=1;
ppispeakon^=1;
// printf("Speakon %i %04X %i\n",speakon,pit.l[2],pit.c[2]);
}
// if (pit.ctrls[2]&0xE) pit.c[2]+=(pit.l[2]*PITCONST);
// spkstat^=0x20;
}
}
void pit_init()
{
io_sethandler(0x0040, 0x0004, pit_read, NULL, NULL, pit_write, NULL, NULL);
}