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a7800: pia timer, timing changes

This commit is contained in:
Steven Hugg 2023-07-08 12:10:45 -05:00
parent 47cabad5ec
commit 5a93bc8b75
1 changed files with 78 additions and 11 deletions
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89
src/machine/atari7800.ts
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@ -28,6 +28,10 @@ interface Atari7800State extends Atari7800StateBase, Atari7800ControlsState {
offset,dll,dlstart : number;
dli,h16,h8 : boolean;
};
pia : {
timer: number;
interval: number;
}
}
const SWCHA = 0;
@ -56,11 +60,14 @@ const Atari7800_KEYCODE_MAP = makeKeycodeMap([
// http://www.ataripreservation.org/websites/freddy.offenga/megazine/ISSUE5-PALNTSC.html
// http://7800.8bitdev.org/index.php/7800_Software_Guide#APPENDIX_4:_FRAME_TIMING
// https://forums.atariage.com/topic/224025-7800-hardware-facts/
const CLK = 3579545;
const linesPerFrame = 262;
const linesPerFrame = 263;
const numVisibleLines = 258-16;
const colorClocksPerLine = 454; // 456?
const colorClocksPerLine = 451; // 451? 452? 456?
const colorClocksPreDMA = 28;
const colorClocksShutdownOther = 16;
const colorClocksShutdownLast = 24;
const audioOversample = 2;
const audioSampleRate = linesPerFrame*60*audioOversample;
@ -185,9 +192,9 @@ class MARIA {
return false;
}
readDMA(a : number) : number {
if (this.isHoley(a))
if (this.isHoley(a)) {
return 0;
else {
} else {
this.cycles += 3;
return this.bus.read(a);
}
@ -197,7 +204,8 @@ class MARIA {
this.cycles = 0;
this.pixels.fill(this.regs[0x0]);
if (this.isDMAEnabled()) {
this.cycles += 16; // TODO: last line in zone gets additional 8 cycles
// last line in zone gets additional 8 cycles
this.cycles += this.offset == 0 ? colorClocksShutdownLast : colorClocksShutdownOther;
// time for a new DLL entry?
if (this.offset < 0) {
this.readDLLEntry(bus);
@ -317,6 +325,8 @@ export class Atari7800 extends BasicMachine implements RasterFrameBased {
cpu : MOS6502;
ram : Uint8Array = new Uint8Array(0x1000);
regs6532 = new Uint8Array(4);
piatimer : number = 0;
timerinterval : number = 1;
tia : TIA = new TIA();
maria : MARIA = new MARIA();
pokey1; //TODO: type
@ -340,7 +350,7 @@ export class Atari7800 extends BasicMachine implements RasterFrameBased {
[0x0040, 0x00ff, 0xff, (a) => { return this.ram[a + 0x800]; }],
[0x0100, 0x013f, 0xff, (a) => { return this.read(a); }], // shadow
[0x0140, 0x01ff, 0x1ff, (a) => { return this.ram[a + 0x800]; }],
[0x0280, 0x02ff, 0x3, (a) => { this.xtracyc++; return this.inputs[a]; }],
[0x0280, 0x02ff, 0x7f, (a) => { this.xtracyc++; return this.readPIA(a); }],
[0x1800, 0x27ff, 0xffff, (a) => { return this.ram[a - 0x1800]; }],
[0x2800, 0x3fff, 0x7ff, (a) => { return this.read(a | 0x2000); }], // shadow
[0x4000, 0xffff, 0xffff, (a) => { return this.rom ? this.rom[a - 0x4000] : 0; }],
@ -353,7 +363,7 @@ export class Atari7800 extends BasicMachine implements RasterFrameBased {
[0x0040, 0x00ff, 0xff, (a,v) => { this.ram[a + 0x800] = v; }],
[0x0100, 0x013f, 0xff, (a,v) => { this.write(a,v); }], // shadow
[0x0140, 0x01ff, 0x1ff, (a,v) => { this.ram[a + 0x800] = v; }],
[0x0280, 0x02ff, 0x3, (a,v) => { this.xtracyc++; this.regs6532[a] = v; /*TODO*/ }],
[0x0280, 0x02ff, 0x7f, (a,v) => { this.xtracyc++; this.writePIA(a,v) }],
[0x1800, 0x27ff, 0xffff, (a,v) => { this.ram[a - 0x1800] = v; }],
[0x2800, 0x3fff, 0x7ff, (a,v) => { this.write(a | 0x2000, v); }], // shadow
[0xbfff, 0xbfff, 0xffff, (a,v) => { }], // TODO: bank switching?
@ -383,16 +393,70 @@ export class Atari7800 extends BasicMachine implements RasterFrameBased {
}
}
readPIA(a:number) : number {
switch (a) {
case 0x0:
case 0x2:
return this.inputs[a]; // SWCHA, SWCHB
case 0x1:
case 0x3:
return this.regs6532[a]; // CTLSWA, CTLSWB
case 0x4:
return this.getPIATimerValue(); // INTIM
default:
return 0;
}
}
writePIA(a:number, v:number) : void {
switch (a) {
case 0x0:
case 0x1:
case 0x2:
case 0x3:
this.regs6532[a] = v;
return;
case 0x14: this.setPIATimer(v, 0); return; // TIM1T
case 0x15: this.setPIATimer(v, 3); return; // TIM8T
case 0x16: this.setPIATimer(v, 6); return; // TIM64T
case 0x17: this.setPIATimer(v, 10); return; // T1024T
case 0x18: this.setPIATimer(v, 6); return; // TIM64TI (TODO)
}
}
setPIATimer(v:number, shift:number) : void {
this.piatimer = (v + 1) << shift;
this.timerinterval = shift;
}
getPIATimerValue() : number {
let t = this.piatimer;
if (t > 0) {
return t >> this.timerinterval;
} else {
return t & 0xff;
}
}
advanceCPU() : number {
var clk = super.advanceCPU();
this.tickPIATimer(clk); // TODO?
if (this.xtracyc) {
clk += this.xtracyc;
this.probe.logClocks(this.xtracyc);
this.tickClocks(this.xtracyc);
this.xtracyc = 0;
}
return clk;
}
tickClocks(clocks:number) {
this.probe.logClocks(clocks);
this.tickPIATimer(clocks);
}
tickPIATimer(clocks:number) {
this.piatimer = Math.max(-256, this.piatimer - clocks);
}
advanceFrame(trap) : number {
var idata = this.pixels;
var iofs = 0;
@ -423,7 +487,7 @@ export class Atari7800 extends BasicMachine implements RasterFrameBased {
if (visible) {
// do DMA for scanline?
let dmaClocks = this.maria.doDMA(this.dmaBus);
this.probe.logClocks(dmaClocks >> 2); // TODO: logDMA
this.tickClocks(dmaClocks >> 2); // TODO: logDMA
mc += dmaClocks;
// copy line to frame buffer
if (idata) {
@ -441,7 +505,7 @@ export class Atari7800 extends BasicMachine implements RasterFrameBased {
while (mc < colorClocksPerLine) {
if (this.maria.WSYNC) {
this.probe.logWait(0);
this.probe.logClocks((colorClocksPerLine - mc) >> 2);
this.tickClocks((colorClocksPerLine - mc) >> 2);
mc = colorClocksPerLine;
break;
}
@ -496,6 +560,8 @@ export class Atari7800 extends BasicMachine implements RasterFrameBased {
this.tia.loadState(state.tia);
this.maria.loadState(state.maria);
this.regs6532.set(state.regs6532);
this.piatimer = state.pia.timer;
this.timerinterval = state.pia.interval;
this.loadControlsState(state);
}
saveState() : Atari7800State {
@ -505,7 +571,8 @@ export class Atari7800 extends BasicMachine implements RasterFrameBased {
tia:this.tia.saveState(),
maria:this.maria.saveState(),
regs6532:this.regs6532.slice(0),
inputs:this.inputs.slice(0)
inputs:this.inputs.slice(0),
pia:{timer:this.piatimer, interval: this.timerinterval}
};
}
loadControlsState(state:Atari7800ControlsState) : void {