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Add Inc(A) and handle Return #10

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Merged
OpenSauce merged 2 commits into from
Mar 15, 2025
Merged

Add Inc(A) and handle Return #10

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d6660be
Handle Inc A and update Makefile
OpenSauce Mar 15, 2025
ca5cc6f
Handle Return
OpenSauce Mar 15, 2025
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5 changes: 4 additions & 1 deletion Makefile
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
.PHONY: all fmt clippy test
.PHONY: all fmt clippy test cpu-test

all: clippy fmt test

Expand All @@ -10,3 +10,6 @@ fmt:

clippy:
cargo clippy --fix --allow-dirty

cpu-test:
cargo run -- roms/blargg/cpu_instrs/cpu_instrs.gb
17 changes: 17 additions & 0 deletions src/emulator/cpu.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,13 @@ impl Cpu {
println!("HALT not implemented");
self.pc.wrapping_add(1)
}
Instruction::Return() => {
let low = mmu.read_byte(self.sp) as u16;
self.sp = self.sp.wrapping_add(1);
let high = mmu.read_byte(self.sp) as u16;
self.sp = self.sp.wrapping_add(1);
(high << 8) | low
}
Instruction::Load(target) => {
match target {
Target::SP => {
Expand Down Expand Up @@ -114,6 +121,13 @@ impl Cpu {
Target::SP => {
self.sp = self.sp.wrapping_add(1);
}
Target::A => {
let value = self.registers.a;
self.registers.a = self.registers.a.wrapping_add(1);
self.registers.f.zero = self.registers.a == 0;
self.registers.f.subtract = false;
self.registers.f.half_carry = (value & 0xF) + 1 > 0xF;
}
Target::B => {
let value = self.registers.b;
self.registers.b = self.registers.b.wrapping_add(1);
Expand Down Expand Up @@ -485,6 +499,7 @@ enum Instruction {
LoadHC(),
LoadHA(),
Restart(u16),
Return(),
}

impl Instruction {
Expand Down Expand Up @@ -551,6 +566,7 @@ impl Instruction {
0x33 => Some(Instruction::Inc(Target::SP)),
0x34 => Some(Instruction::IncHl()),
0x36 => Some(Instruction::LoadN8(Target::HL)),
0x3C => Some(Instruction::Inc(Target::A)),
0x3E => Some(Instruction::LoadN8(Target::A)),
0x76 => Some(Instruction::Halt()),
0x80 => Some(Instruction::Add(Target::B)),
Expand All @@ -564,6 +580,7 @@ impl Instruction {
0xC2 => Some(Instruction::Jump(JumpTest::NotZero)),
0xC3 => Some(Instruction::Jump(JumpTest::Always)),
0xCA => Some(Instruction::Jump(JumpTest::Zero)),
0xC9 => Some(Instruction::Return()),
0xD2 => Some(Instruction::Jump(JumpTest::NotCarry)),
0xDA => Some(Instruction::Jump(JumpTest::Carry)),
0xE0 => Some(Instruction::LoadHC()),
Expand Down