diff options
Diffstat (limited to 'src/mos6502.rs')
| -rw-r--r-- | src/mos6502.rs | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/src/mos6502.rs b/src/mos6502.rs index 45c4166..59e17de 100644 --- a/src/mos6502.rs +++ b/src/mos6502.rs @@ -388,22 +388,19 @@ mod ops { } fn rol(cpu: &mut CPU) { - let mut status = cpu.status & !(CARRY_FLAG | ZERO_FLAG | NEG_FLAG); let res = match cpu.acc { true => { - let old = cpu.a; - let t = old.rotate_left(1); - cpu.a = t as u8; - status |= old >> 7 as u8; /* carry flag */ + let t = (cpu.a as u16) << 1; + cpu.a = t as u8 | cpu.get_carry(); t }, false => { - let old = cpu.mem.read(cpu.ea); - let t = old.rotate_left(1); - cpu.mem.write(cpu.ea, t as u8); - status |= old >> 7 as u8; /* carry flag */ + let t = (cpu.mem.read(cpu.ea) as u16) << 1; + cpu.mem.write(cpu.ea, t as u8 | cpu.get_carry()); t }}; + let mut status = cpu.status & !(CARRY_FLAG | ZERO_FLAG | NEG_FLAG); + status |= (res >> 8) as u8; /* carry flag */ check_zero!(status, res); check_neg!(status, res); cpu.status = status; @@ -414,16 +411,16 @@ mod ops { let res = match cpu.acc { true => { let old = cpu.a; - let t = old.rotate_right(1); - cpu.a = t as u8; - status |= old & 1 as u8; /* carry flag */ + let t = old >> 1; + cpu.a = t as u8 | (cpu.get_carry() << 7); + status |= (old & 1) as u8; /* carry flag */ t }, false => { let old = cpu.mem.read(cpu.ea); - let t = old.rotate_right(1); - cpu.mem.write(cpu.ea, t as u8); - status |= old & 1 as u8; /* carry flag */ + let t = old >> 1; + cpu.mem.write(cpu.ea, t as u8 | (cpu.get_carry() << 7)); + status |= (old & 1) as u8; /* carry flag */ t }}; check_zero!(status, res); @@ -751,8 +748,9 @@ impl<'a> CPU<'a> { for i in 0..len as u16 { code[i as usize] = self.mem.read(pc + i); } - println!("0x{:04x} {} a:{} x:{} y:{}", - pc, disasm::parse(opcode as u8, &code[1..]), self.a, self.x, self.y); + //println!("0x{:04x} {} a:{:02x} x:{:02x} y:{:02x} s: {:02x} sp: {:02x}", + // pc, disasm::parse(opcode as u8, &code[1..]), + // self.a, self.x, self.y, self.status, self.sp); /* update opr pointing to operands of current inst */ self.opr = pc.wrapping_add(1); /* update program counter pointing to next inst */ |