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apple2: don't modify uploaded ROMs with RTS byte

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This commit is contained in:
Micah Cowan 2022-01-28 23:32:10 -08:00
parent fc59dd30c3
commit 3681bc65e8
1 changed files with 5 additions and 1 deletions
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6
src/machine/apple2.ts
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@ -120,6 +120,11 @@ export class AppleII extends BasicScanlineMachine implements AcceptsBIOS {
super();
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
@ -163,7 +168,6 @@ export class AppleII extends BasicScanlineMachine implements AcceptsBIOS {
console.log("will load BIOS to end of memory anyway...");
}
this.bios = Uint8Array.from(data);
this.bios[0xD39A - (0x10000 - this.bios.length)] = 0x60; // $d39a = RTS
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