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Added stuff. Fixed bug.

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Data Pointer value now properly displayed in debug mode.
Added conditional calls to match conditional branches.
This commit is contained in:
Anachronaut
2024-10-31 13:30:15 -04:00
committed by GitHub
parent f8848adf8c
commit 228cf0593a
12 changed files with 414 additions and 44 deletions
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Source/Emulator/cpu.c
+59 -32
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@@ -31,6 +31,31 @@ void genericBranch(CPURegisters *cpu){
cpu->ProgramCounter = DestinationAddress-1;
}
void genericCall(CPURegisters *cpu){
// Order, low byte, high byte
cpu->Data[cpu->StackPointer] = cpu->ProgramCounter & 0xFF;
cpu->StackPointer--;
cpu->Data[cpu->StackPointer] = (cpu->ProgramCounter >> 8) & 0xFF;
cpu->StackPointer--;
// Push the Data Pointer to the Stack.
// Order, low byte, high byte
cpu->Data[cpu->StackPointer] = cpu->DataPointer & 0xFF;
cpu->StackPointer--;
cpu->Data[cpu->StackPointer] = (cpu->DataPointer >> 8) & 0xFF;
cpu->StackPointer--;
// Push Q to the Stack.
cpu->Data[cpu->StackPointer] = cpu->Q;
cpu->StackPointer--;
// Push B to the Stack.
cpu->Data[cpu->StackPointer] = cpu->B;
cpu->StackPointer--;
// Push A to the Stack.
cpu->Data[cpu->StackPointer] = cpu->A;
cpu->StackPointer--;
// Perform a Generic Branch to the Address.
genericBranch(cpu);
}
uint8_t executeOperation(uint8_t Instruction, CPURegisters *cpu) {
switch(Instruction) {
// 0x - Arithmetic and Logic Operations.
@@ -131,31 +156,41 @@ uint8_t executeOperation(uint8_t Instruction, CPURegisters *cpu) {
}
break;
case 0x14:
// CALL - Push the Program Counter to the Stack, and perform an immediate branch.
// Order, low byte, high byte
cpu->Data[cpu->StackPointer] = cpu->ProgramCounter & 0xFF;
cpu->StackPointer--;
cpu->Data[cpu->StackPointer] = (cpu->ProgramCounter >> 8) & 0xFF;
cpu->StackPointer--;
// Push the Data Pointer to the Stack.
// Order, low byte, high byte
cpu->Data[cpu->StackPointer] = cpu->DataPointer & 0xFF;
cpu->StackPointer--;
cpu->Data[cpu->StackPointer] = (cpu->DataPointer >> 8) & 0xFF;
cpu->StackPointer--;
// Push Q to the Stack.
cpu->Data[cpu->StackPointer] = cpu->Q;
cpu->StackPointer--;
// Push B to the Stack.
cpu->Data[cpu->StackPointer] = cpu->B;
cpu->StackPointer--;
// Push A to the Stack.
cpu->Data[cpu->StackPointer] = cpu->A;
cpu->StackPointer--;
// Perform a Generic Branch to the Address.
genericBranch(cpu);
// BRC - Do an immediate branch if the Carry Flag is set.
if (cpu->Status & 0x01) {
genericBranch(cpu);
} else {
cpu->ProgramCounter+=2;
}
break;
case 0x15:
case 0x17:
// CALL - Push the Program Counter to the Stack, and perform an immediate branch.
genericCall(cpu);
break;
case 0x18:
// CALLA
if (cpu->A == 0) {
genericCall(cpu);
}
break;
case 0x19:
// CALLB
if (cpu->B == 0) {
genericCall(cpu);
}
break;
case 0x1A:
// CALLQ
if (cpu->Q == 0) {
genericCall(cpu);
}
case 0x1B:
// CALLCF
if (cpu->Status & 0x01) {
genericCall(cpu);
}
break;
case 0x1F:
// RET - Return from subroutine, restore the registers and set the Program Counter to the Return Address.
// Pop A from the Stack.
cpu->StackPointer++;
@@ -179,14 +214,6 @@ uint8_t executeOperation(uint8_t Instruction, CPURegisters *cpu) {
// Add 2 to the Program Counter to skip over the address when it returns.
cpu->ProgramCounter += 2;
break;
case 0x16:
// BRC - Do an immediate branch is the Carry Flag is set.
if (cpu->Status & 0x01) {
genericBranch(cpu);
} else {
cpu->ProgramCounter+=2;
}
break;
//
// 2x - Register Operations:
//