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Merge pull request #93 from micahcowan/apple2

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Apple2: Allow uploaded firmware ROM replacement
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Steven Hugg 2022-02-01 11:35:45 -06:00 committed by GitHub
commit e439f16249
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1 changed files with 62 additions and 19 deletions
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81
src/machine/apple2.ts
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@ -1,6 +1,6 @@
import { MOS6502, MOS6502State } from "../common/cpu/MOS6502";
import { Bus, BasicScanlineMachine, SavesState } from "../common/devices";
import { Bus, BasicScanlineMachine, SavesState, AcceptsBIOS } from "../common/devices";
import { KeyFlags } from "../common/emu"; // TODO
import { hex, lzgmini, stringToByteArray, RGBA, printFlags } from "../common/util";
@ -33,7 +33,7 @@ interface SlotDevice extends Bus {
readConst(address: number) : number;
}
export class AppleII extends BasicScanlineMachine {
export class AppleII extends BasicScanlineMachine implements AcceptsBIOS {
// approx: http://www.cs.columbia.edu/~sedwards/apple2fpga/
cpuFrequency = 1022727;
@ -66,17 +66,47 @@ export class AppleII extends BasicScanlineMachine {
// fake disk drive that loads program into RAM
fakeDrive : SlotDevice = {
readROM: (a) => {
switch (a) {
// JMP VM_BASE
case 0: {
// load program into RAM
if (this.rom)
this.ram.set(this.rom.slice(HDR_SIZE), PGM_BASE);
return 0x4c;
}
case 1: return VM_BASE&0xff;
case 2: return (VM_BASE>>8)&0xff;
default: return 0;
var pc = this.cpu.getPC();
if (pc >= 0xC600 && pc < 0xC700) {
// We're reading code to EXECUTE.
// Load the built program directly into memory, and "read"
// a JMP directly to it.
//console.log(`fakeDrive (EXEC): ${a.toString(16)}`);
switch (a) {
// JMP VM_BASE
case 0:
// SHOULD load program into RAM here, but have to do it
// below instead.
return 0;
case 1: return VM_BASE&0xff;
case 2: return (VM_BASE>>8)&0xff;
default: return 0;
}
}
else {
// We're reading code, but not executing it.
// This is probably the Monitor routine to identify whether
// this slot is a Disk ][ drive, so... give it what it wants.
//console.log(`fakeDrive (NOEX): ${a.toString(16)}`);
switch (a) {
case 0:
// Actually, if we get here, we probably ARE being
// executed. For some reason, the instruction at $C600
// gets read for execution, BEFORE the PC gets set to
// the correct location. So we handle loading the program
// into RAM and returning the JMP here, instead of above
// where it would otherwise belong.
if (this.rom) {
console.log(`Loading program into Apple ][ RAM at \$${PGM_BASE.toString(16)}`);
this.ram.set(this.rom.slice(HDR_SIZE), PGM_BASE);
}
return 0x4c; // JMP
case 1: return 0x20;
case 3: return 0x00;
case 5: return 0x03;
case 7: return 0x3c;
default: return 0;
}
}
},
readConst: (a) => {
@ -88,12 +118,13 @@ export class AppleII extends BasicScanlineMachine {
constructor() {
super();
this.bios = new lzgmini().decode(stringToByteArray(atob(APPLEIIGO_LZG)));
this.bios[0x39a] = 0x60; // $d39a = RTS
this.ram.set(this.bios, 0xd000);
this.ram[0xbf00] = 0x4c; // fake DOS detect for C
this.ram[0xbf6f] = 0x01; // fake DOS detect for C
this.loadBIOS(new lzgmini().decode(stringToByteArray(atob(APPLEIIGO_LZG))));
this.connectCPUMemoryBus(this);
// This line is inappropriate for real ROMs, but was there for
// the APPLE][GO ROM, so keeping it only in the constructor, for
// that special case (in case it really is important for this
// address to be an RTS).
this.bios[0xD39A - (0x10000 - this.bios.length)] = 0x60; // $d39a = RTS
}
saveState() : AppleIIState {
// TODO: automagic
@ -131,6 +162,16 @@ export class AppleII extends BasicScanlineMachine {
loadControlsState(s:AppleIIControlsState) {
this.kbdlatch = s.kbdlatch;
}
loadBIOS(data, title?) {
if (data.length != 0x3000) {
console.log(`apple2 loadBIOS !!!WARNING!!!: BIOS wants length 0x3000, but BIOS '${title}' has length 0x${data.length.toString(16)}`);
console.log("will load BIOS to end of memory anyway...");
}
this.bios = Uint8Array.from(data);
this.ram.set(this.bios, 0x10000 - this.bios.length);
this.ram[0xbf00] = 0x4c; // fake DOS detect for C
this.ram[0xbf6f] = 0x01; // fake DOS detect for C
}
loadROM(data) {
if (data.length == 35*16*256) { // is it a disk image?
var diskii = new DiskII(this, data);
@ -145,6 +186,8 @@ export class AppleII extends BasicScanlineMachine {
this.auxRAMselected = false;
this.auxRAMbank = 1;
this.writeinhibit = true;
this.ram.fill(0, 0x300, 0x400); // Clear soft-reset vector
// (force hard reset)
this.skipboot();
}
skipboot() {
@ -164,7 +207,7 @@ export class AppleII extends BasicScanlineMachine {
return this.ram[address];
} else if (address >= 0xd000) {
if (!this.auxRAMselected)
return this.bios[address - 0xd000];
return this.bios[address - (0x10000 - this.bios.length)];
else if (address >= 0xe000)
return this.ram[address];
else