diff --git a/src/instruction.rs b/src/instruction.rs index 3d0b57d..9ddb5ae 100644 --- a/src/instruction.rs +++ b/src/instruction.rs @@ -522,6 +522,7 @@ impl Instruction { cycles } MATHTarget::ImmediateByte(n) => { + // ADC A, n | Add immediate byte plus the carry flag to A let mut flags: Flags = cpu.register(Register::Flag).into(); let value = n + (flags.c as u8); let sum = Self::add_u8s(cpu.register(Register::A), value, &mut flags); @@ -565,6 +566,7 @@ impl Instruction { cycles } MATHTarget::ImmediateByte(n) => { + // SUB n | Subtract the immediate byte from register A, then store in A let mut flags: Flags = cpu.register(Register::Flag).into(); let diff = Self::sub_u8s(cpu.register(Register::A), n, &mut flags); @@ -609,6 +611,8 @@ impl Instruction { cycles } MATHTarget::ImmediateByte(n) => { + // SBC A, n | Subtract the value from immediate byte from A, add the carry flag and then store in A + // FIXME: The Fixme aboe applies to this variant as well let mut flags: Flags = cpu.register(Register::Flag).into(); let value = n + (flags.c as u8); let diff = Self::sub_u8s(cpu.register(Register::A), value, &mut flags); @@ -657,6 +661,7 @@ impl Instruction { cycles } MATHTarget::ImmediateByte(n) => { + // AND n | Bitwise AND immediate byte and register A, sotre in register A let mut flags: Flags = cpu.register(Register::Flag).into(); let result = cpu.register(Register::A) & n; @@ -709,6 +714,7 @@ impl Instruction { cycles } MATHTarget::ImmediateByte(n) => { + // XOR n | Bitwise XOR immediate byte and register A, store in register A let mut flags: Flags = cpu.register(Register::Flag).into(); let result = cpu.register(Register::A) ^ n; @@ -761,6 +767,7 @@ impl Instruction { cycles } MATHTarget::ImmediateByte(n) => { + // OR n | Bitwise OR on immediate byte n and register A, store in register A let mut flags: Flags = cpu.register(Register::Flag).into(); let result = cpu.register(Register::A) | n; @@ -806,6 +813,7 @@ impl Instruction { cycles } MATHTarget::ImmediateByte(n) => { + // CP n | Same behaviour as SUB, except the result is not stored, let mut flags: Flags = cpu.register(Register::Flag).into(); let _ = Self::sub_u8s(cpu.register(Register::A), n, &mut flags); @@ -1050,6 +1058,7 @@ impl Instruction { cpu.set_register_pair(RegisterPair::SP, sp_value); Cycles(16) } + _ => unimplemented!(), } }