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basic ppu background rendering

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Lauchmelder 2022-03-03 17:29:56 +01:00
parent f9f401c6c0
commit aef80e42fb
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GPG key ID: C2403C69D78F011D
21 changed files with 468 additions and 41 deletions
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57
src/CPU.cpp
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@ -150,6 +150,7 @@ void CPU::CreateInstructionTable()
InstructionTable[0x48] = NEW_INSTRUCTION(PHA, IMP, 1, 3);
InstructionTable[0x49] = NEW_INSTRUCTION(EOR, IMM, 2, 2);
InstructionTable[0x4A] = NEW_INSTRUCTION(LSR, ACC, 1, 2);
InstructionTable[0x4B] = NEW_ILLGL_INSTR(ALR, IMM, 2, 2);
InstructionTable[0x4C] = NEW_INSTRUCTION(JMP, ABS, 3, 3);
InstructionTable[0x4D] = NEW_INSTRUCTION(EOR, ABS, 3, 4);
InstructionTable[0x4E] = NEW_INSTRUCTION(LSR, ABS, 3, 6);
@ -212,6 +213,7 @@ void CPU::CreateInstructionTable()
InstructionTable[0x88] = NEW_INSTRUCTION(DEY, IMP, 1, 2);
InstructionTable[0x89] = NEW_ILLGL_INSTR(NOP, IMM, 2, 2);
InstructionTable[0x8A] = NEW_INSTRUCTION(TXA, IMP, 1, 2);
InstructionTable[0x8B] = NEW_ILLGL_INSTR(ANE, IMM, 2, 2);
InstructionTable[0x8C] = NEW_INSTRUCTION(STY, ABS, 3, 4);
InstructionTable[0x8D] = NEW_INSTRUCTION(STA, ABS, 3, 4);
InstructionTable[0x8E] = NEW_INSTRUCTION(STX, ABS, 3, 4);
@ -239,6 +241,7 @@ void CPU::CreateInstructionTable()
InstructionTable[0xA8] = NEW_INSTRUCTION(TAY, IMP, 1, 2);
InstructionTable[0xA9] = NEW_INSTRUCTION(LDA, IMM, 2, 2);
InstructionTable[0xAA] = NEW_INSTRUCTION(TAX, IMP, 1, 2);
InstructionTable[0xAB] = NEW_ILLGL_INSTR(LXA, IMM, 2, 2);
InstructionTable[0xAC] = NEW_INSTRUCTION(LDY, ABS, 3, 4);
InstructionTable[0xAD] = NEW_INSTRUCTION(LDA, ABS, 3, 4);
InstructionTable[0xAE] = NEW_INSTRUCTION(LDX, ABS, 3, 4);
@ -352,6 +355,20 @@ void CPU::Reset()
halted = false;
}
void CPU::IRQ()
{
if (status.Flag.InterruptDisable)
return;
Push(pc.Bytes.hi);
Push(pc.Bytes.lo);
Push(status.Raw | (0x20 << 4));
status.Flag.InterruptDisable = 1;
pc.Bytes.lo = Read(0xFFFE);
pc.Bytes.hi = Read(0xFFFF);
}
void CPU::NMI()
{
Push(pc.Bytes.hi);
@ -484,6 +501,20 @@ void CPU::ADC()
status.Flag.Carry = ((result & 0x100) == 0x100);
}
void CPU::ALR()
{
FetchValue();
acc &= fetchedVal;
status.Flag.Carry = ((acc & 0x01) == 0x01);
acc >>= 1;
status.Flag.Negative = 0;
CHECK_ZERO(acc);
additionalCycles = 0;
}
void CPU::AND()
{
FetchValue();
@ -493,6 +524,19 @@ void CPU::AND()
CHECK_ZERO(acc);
}
void CPU::ANE()
{
FetchValue();
Byte result = (acc | 0xFF) & idx & fetchedVal;
acc = result;
CHECK_NEGATIVE(result);
CHECK_ZERO(result);
additionalCycles = 0;
}
void CPU::ASL()
{
FetchValue();
@ -847,6 +891,19 @@ void CPU::LSR()
Write(absoluteAddress.Raw, fetchedVal);
}
void CPU::LXA()
{
FetchValue();
Byte result = (acc & 0xFF) & fetchedVal;
acc = result;
idx = result;
CHECK_NEGATIVE(result);
CHECK_ZERO(result);
additionalCycles = 0;
}
void CPU::NOP()
{
// Nothing to do