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Memory controller implemented.

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This commit is contained in:
Anachronaut
2026-08-15 20:43:53 -04:00
parent c4b2c27a2d
commit 04dfcd707b
32 changed files with 1842 additions and 21 deletions
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Source/Emulator/cpu.c
+39 -5
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@@ -67,6 +67,25 @@ static uint8_t enterInterrupt(CPURegisters *cpu, uint16_t base, uint8_t index, u
return 0;
}
// A device that refused what it was asked stops the machine where it stands, rather than
// raising a line and letting execution carry on past the mistake. The frame carries the
// address of the instruction that asked, so a handler can see which one it was, and so a
// bare RETI meets it again the way every other fault on this machine does.
//
// Returns 1 if the machine has stopped because nothing was installed to catch it.
static uint8_t answerRefusal(CPURegisters *cpu, uint16_t site) {
uint8_t refusal = takeRefusal();
if (refusal == 0) {
return 0;
}
if (enterInterrupt(cpu, SOFTWARE_VECTOR_BASE, refusal, site)) {
cpu->Fault = FAULT_DEVICE_REFUSED;
cpu->FaultVector = refusingPort();
cpu->ProgramCounter = site - 1;
}
return 0;
}
void initializeCPU(CPURegisters *cpu, uint8_t *programMemory, uint8_t *dataMemory) {
cpu->A = 0;
cpu->B = 0;
@@ -544,33 +563,48 @@ uint8_t executeOperation(uint8_t Instruction, CPURegisters *cpu) {
//
// Dx - Output Operations:
//
case 0xD0:
case 0xD0: {
// OUTQ - Write the value of Q to an output port.
uint16_t site = cpu->ProgramCounter;
cpu->ProgramCounter++;
OutputHandler(cpu->Q, cpu->Program[cpu->ProgramCounter]);
answerRefusal(cpu, site);
}
break;
case 0xD1:
case 0xD1: {
// OUTA - Write the value of A to an output port.
uint16_t site = cpu->ProgramCounter;
cpu->ProgramCounter++;
OutputHandler(cpu->A, cpu->Program[cpu->ProgramCounter]);
answerRefusal(cpu, site);
}
break;
case 0xD2:
case 0xD2: {
// OUTB - Write the value of B to an output port.
uint16_t site = cpu->ProgramCounter;
cpu->ProgramCounter++;
OutputHandler(cpu->B, cpu->Program[cpu->ProgramCounter]);
answerRefusal(cpu, site);
}
break;
//
// Ex - Input Operations:
//
case 0xE0:
case 0xE0: {
// INA - Read an Input to A.
uint16_t site = cpu->ProgramCounter;
cpu->ProgramCounter++;
cpu->A = InputHandler(cpu->Program[cpu->ProgramCounter]);
answerRefusal(cpu, site);
}
break;
case 0xE1:
case 0xE1: {
// INB - Read an Input to B.
uint16_t site = cpu->ProgramCounter;
cpu->ProgramCounter++;
cpu->B = InputHandler(cpu->Program[cpu->ProgramCounter]);
answerRefusal(cpu, site);
}
break;
//
// Fx - Special Operations: