2014-09-30 04:28:46 +00:00
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// Copyright (C) 2014 The 6502-rs Developers
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions
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// are met:
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// 1. Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the distribution.
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// 3. Neither the names of the copyright holders nor the names of any
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// contributors may be used to endorse or promote products derived from this
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// software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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2014-10-04 21:47:32 +00:00
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use std;
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2014-10-04 20:33:42 +00:00
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2014-10-20 01:37:43 +00:00
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use address::{Address, AddressDiff};
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2014-10-04 20:33:42 +00:00
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use instruction;
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2014-10-04 20:47:42 +00:00
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use instruction::{DecodedInstr};
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2014-09-30 04:28:46 +00:00
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use memory::Memory;
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2014-10-25 23:04:52 +00:00
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use registers::{ Registers, StackPointer, Status, StatusArgs };
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2014-11-02 19:23:38 +00:00
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use registers::{ PS_NEGATIVE, PS_DECIMAL_MODE, PS_OVERFLOW, PS_ZERO, PS_CARRY,
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PS_DISABLE_INTERRUPTS };
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2014-09-30 04:28:46 +00:00
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pub struct Machine {
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pub registers: Registers,
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pub memory: Memory
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}
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impl Machine {
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pub fn new() -> Machine {
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Machine{
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registers: Registers::new(),
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memory: Memory::new()
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}
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}
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2014-10-20 01:37:43 +00:00
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2014-09-30 04:28:46 +00:00
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pub fn reset(&mut self) {
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*self = Machine::new();
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}
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2014-10-01 22:02:45 +00:00
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2014-10-04 20:33:42 +00:00
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pub fn fetch_next_and_decode(&mut self) -> Option<DecodedInstr> {
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let x: u8 = self.memory.get_byte(self.registers.program_counter);
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2014-10-07 04:07:09 +00:00
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match instruction::OPCODES[x as uint] {
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2014-10-04 20:33:42 +00:00
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Some((instr, am)) => {
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let extra_bytes = am.extra_bytes();
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let num_bytes = AddressDiff(1) + extra_bytes;
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2014-10-01 22:19:28 +00:00
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2014-10-04 20:33:42 +00:00
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let data_start = self.registers.program_counter
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+ AddressDiff(1);
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2014-10-01 22:02:45 +00:00
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2014-10-04 20:33:42 +00:00
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let slice = self.memory.get_slice(data_start, extra_bytes);
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let am_out = am.process(self, slice);
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// Increment program counter
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self.registers.program_counter =
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self.registers.program_counter + num_bytes;
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Some((instr, am_out))
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}
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_ => None
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2014-10-01 22:38:07 +00:00
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}
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2014-10-04 20:33:42 +00:00
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}
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pub fn execute_instruction(&mut self, decoded_instr: DecodedInstr) {
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match decoded_instr {
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(instruction::ADC, instruction::UseImmediate(val)) => {
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2014-10-25 22:42:48 +00:00
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debug!("add with carry immediate: {}", val);
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2014-10-04 20:33:42 +00:00
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self.add_with_carry(val as i8);
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2014-11-02 19:23:38 +00:00
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}
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2014-10-04 20:33:42 +00:00
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(instruction::ADC, instruction::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr) as i8;
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2014-10-25 22:42:48 +00:00
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debug!("add with carry. address: {}. value: {}", addr, val);
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2014-10-04 20:33:42 +00:00
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self.add_with_carry(val);
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2014-11-02 19:23:38 +00:00
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}
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2014-10-04 20:33:42 +00:00
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2014-11-07 00:17:38 +00:00
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(instruction::AND, instruction::UseImmediate(val)) => {
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self.and(val as i8);
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}
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(instruction::AND, instruction::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr) as i8;
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self.and(val as i8);
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}
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2014-11-03 02:56:02 +00:00
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(instruction::ASL, instruction::UseImplied) => {
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// Accumulator mode
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let mut val = self.registers.accumulator as u8;
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Machine::shift_left_with_flags(&mut val,
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&mut self.registers.status);
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self.registers.accumulator = val as i8;
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}
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(instruction::ASL, instruction::UseAddress(addr)) => {
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Machine::shift_left_with_flags(
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self.memory.get_byte_mut_ref(addr),
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&mut self.registers.status);
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}
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2014-10-25 23:39:36 +00:00
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(instruction::BIT, instruction::UseAddress(addr)) => {
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let a: u8 = self.registers.accumulator as u8;
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let m: u8 = self.memory.get_byte(addr);
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let res = a & m;
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// The zero flag is set based on the result of the 'and'.
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let is_zero = 0 == res;
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// The N flag is set to bit 7 of the byte from memory.
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let bit7 = 0 != (0x80 & res);
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// The V flag is set to bit 6 of the byte from memory.
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let bit6 = 0 != (0x40 & res);
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self.registers.status.set_with_mask(
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PS_ZERO | PS_NEGATIVE | PS_OVERFLOW,
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Status::new(StatusArgs { zero: is_zero,
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negative: bit7,
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overflow: bit6,
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..StatusArgs::none() } ));
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}
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2014-10-25 22:30:05 +00:00
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(instruction::BMI, instruction::UseRelative(rel)) => {
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let addr = self.registers.program_counter
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+ AddressDiff(rel as i32);
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2014-10-25 22:42:48 +00:00
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debug!("branch if minus relative. address: {}", addr);
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2014-10-25 22:30:05 +00:00
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self.branch_if_minus(addr);
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2014-11-02 19:23:38 +00:00
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}
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(instruction::CLC, instruction::UseImplied) => {
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self.registers.status.and(!PS_CARRY);
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}
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(instruction::CLD, instruction::UseImplied) => {
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self.registers.status.and(!PS_DECIMAL_MODE);
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}
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(instruction::CLI, instruction::UseImplied) => {
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self.registers.status.and(!PS_DISABLE_INTERRUPTS);
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}
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(instruction::CLV, instruction::UseImplied) => {
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self.registers.status.and(!PS_OVERFLOW);
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}
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2014-10-25 22:30:05 +00:00
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2014-10-20 01:20:19 +00:00
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(instruction::DEC, instruction::UseAddress(addr)) => {
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self.decrement_memory(addr)
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}
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2014-10-08 03:52:38 +00:00
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(instruction::DEX, instruction::UseImplied) => {
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self.dec_x();
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2014-11-02 19:23:38 +00:00
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}
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2014-10-20 01:37:43 +00:00
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2014-11-02 20:40:34 +00:00
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(instruction::INC, instruction::UseAddress(addr)) => {
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let m = self.memory.get_byte(addr);
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let m = m + 1;
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self.memory.set_byte(addr, m);
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let i = m as i8;
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Machine::set_flags_from_i8(&mut self.registers.status, i);
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}
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(instruction::INX, instruction::UseImplied) => {
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let x = self.registers.index_x + 1;
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self.load_x_register(x);
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}
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(instruction::INY, instruction::UseImplied) => {
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let y = self.registers.index_y + 1;
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self.load_y_register(y);
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}
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2014-10-20 01:37:43 +00:00
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(instruction::JMP, instruction::UseAddress(addr)) => {
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self.jump(addr)
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2014-11-02 19:23:38 +00:00
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}
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2014-10-08 03:52:38 +00:00
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2014-10-04 20:33:42 +00:00
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(instruction::LDA, instruction::UseImmediate(val)) => {
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2014-10-25 22:42:48 +00:00
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debug!("load A immediate: {}", val);
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2014-10-04 20:33:42 +00:00
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self.load_accumulator(val as i8);
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2014-11-02 19:23:38 +00:00
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}
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2014-10-04 20:33:42 +00:00
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(instruction::LDA, instruction::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr);
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2014-10-25 22:42:48 +00:00
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debug!("load A. address: {}. value: {}", addr, val);
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2014-10-04 20:33:42 +00:00
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self.load_accumulator(val as i8);
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2014-11-02 19:23:38 +00:00
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}
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2014-10-04 20:33:42 +00:00
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(instruction::LDX, instruction::UseImmediate(val)) => {
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2014-10-25 22:42:48 +00:00
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debug!("load X immediate: {}", val);
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2014-10-04 20:33:42 +00:00
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self.load_x_register(val as i8);
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2014-11-02 19:23:38 +00:00
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}
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2014-10-04 20:33:42 +00:00
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(instruction::LDX, instruction::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr);
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2014-10-25 22:42:48 +00:00
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debug!("load X. address: {}. value: {}", addr, val);
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2014-10-04 20:33:42 +00:00
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self.load_x_register(val as i8);
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2014-11-02 19:23:38 +00:00
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}
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2014-10-04 20:33:42 +00:00
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(instruction::LDY, instruction::UseImmediate(val)) => {
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2014-10-25 22:42:48 +00:00
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debug!("load Y immediate: {}", val);
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2014-10-04 20:33:42 +00:00
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self.load_y_register(val as i8);
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2014-11-02 19:23:38 +00:00
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}
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2014-10-04 20:33:42 +00:00
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(instruction::LDY, instruction::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr);
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2014-10-25 22:42:48 +00:00
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debug!("load Y. address: {}. value: {}", addr, val);
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2014-10-04 20:33:42 +00:00
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self.load_y_register(val as i8);
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2014-11-02 19:23:38 +00:00
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}
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2014-11-02 20:40:34 +00:00
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(instruction::LSR, instruction::UseImplied) => {
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// Accumulator mode
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let mut val = self.registers.accumulator as u8;
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Machine::shift_right_with_flags(&mut val,
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&mut self.registers.status);
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self.registers.accumulator = val as i8;
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}
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(instruction::LSR, instruction::UseAddress(addr)) => {
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Machine::shift_right_with_flags(
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self.memory.get_byte_mut_ref(addr),
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&mut self.registers.status);
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}
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2014-11-03 02:56:02 +00:00
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(instruction::PHA, instruction::UseImplied) => {
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// Push accumulator
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let val = self.registers.accumulator as u8;
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self.push_on_stack(val);
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}
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(instruction::PHP, instruction::UseImplied) => {
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// Push status
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let val = self.registers.status.bits();
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self.push_on_stack(val);
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}
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(instruction::PLA, instruction::UseImplied) => {
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// Pull accumulator
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let val: u8 = self.pull_from_stack();
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self.registers.accumulator = val as i8;
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}
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(instruction::PLP, instruction::UseImplied) => {
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// Pull status
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let val: u8 = self.pull_from_stack();
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// The `truncate` here won't do anything because we have a
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// constant for the single unused flags bit. This probably
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// corresponds to the behavior of the 6502...? FIXME: verify
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self.registers.status = Status::from_bits_truncate(val);
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}
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(instruction::ROL, instruction::UseImplied) => {
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// Accumulator mode
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let mut val = self.registers.accumulator as u8;
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Machine::rotate_left_with_flags(&mut val,
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&mut self.registers.status);
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self.registers.accumulator = val as i8;
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}
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(instruction::ROL, instruction::UseAddress(addr)) => {
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Machine::rotate_left_with_flags(
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self.memory.get_byte_mut_ref(addr),
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&mut self.registers.status);
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}
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(instruction::ROR, instruction::UseImplied) => {
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// Accumulator mode
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let mut val = self.registers.accumulator as u8;
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Machine::rotate_right_with_flags(&mut val,
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&mut self.registers.status);
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self.registers.accumulator = val as i8;
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}
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(instruction::ROR, instruction::UseAddress(addr)) => {
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Machine::rotate_right_with_flags(
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self.memory.get_byte_mut_ref(addr),
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&mut self.registers.status);
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}
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2014-11-02 19:23:38 +00:00
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(instruction::SBC, instruction::UseImmediate(val)) => {
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debug!("subtract with carry immediate: {}", val);
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self.subtract_with_carry(val as i8);
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}
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(instruction::SBC, instruction::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr) as i8;
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debug!("subtract with carry. address: {}. value: {}",
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addr, val);
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self.subtract_with_carry(val);
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}
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(instruction::SEC, instruction::UseImplied) => {
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self.registers.status.or(PS_CARRY);
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}
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(instruction::SED, instruction::UseImplied) => {
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self.registers.status.or(PS_DECIMAL_MODE);
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}
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(instruction::SEI, instruction::UseImplied) => {
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self.registers.status.or(PS_DISABLE_INTERRUPTS);
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}
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2014-10-04 20:33:42 +00:00
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2014-10-25 22:30:05 +00:00
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(instruction::STA, instruction::UseAddress(addr)) => {
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self.memory.set_byte(addr, self.registers.accumulator as u8);
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2014-11-02 19:23:38 +00:00
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}
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2014-10-25 22:30:05 +00:00
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(instruction::STX, instruction::UseAddress(addr)) => {
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self.memory.set_byte(addr, self.registers.index_x as u8);
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2014-11-02 19:23:38 +00:00
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}
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2014-10-25 22:30:05 +00:00
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(instruction::STY, instruction::UseAddress(addr)) => {
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self.memory.set_byte(addr, self.registers.index_y as u8);
|
2014-11-02 19:23:38 +00:00
|
|
|
}
|
2014-10-25 22:30:05 +00:00
|
|
|
|
2014-10-25 23:04:52 +00:00
|
|
|
(instruction::TAX, instruction::UseImplied) => {
|
|
|
|
let val = self.registers.accumulator;
|
|
|
|
self.load_x_register(val);
|
2014-11-02 19:23:38 +00:00
|
|
|
}
|
2014-10-25 23:04:52 +00:00
|
|
|
(instruction::TAY, instruction::UseImplied) => {
|
|
|
|
let val = self.registers.accumulator;
|
|
|
|
self.load_y_register(val);
|
2014-11-02 19:23:38 +00:00
|
|
|
}
|
2014-10-25 23:04:52 +00:00
|
|
|
(instruction::TSX, instruction::UseImplied) => {
|
|
|
|
let StackPointer(val) = self.registers.stack_pointer;
|
|
|
|
let val = val as i8;
|
|
|
|
self.load_x_register(val);
|
2014-11-02 19:23:38 +00:00
|
|
|
}
|
2014-10-25 23:04:52 +00:00
|
|
|
(instruction::TXA, instruction::UseImplied) => {
|
|
|
|
let val = self.registers.index_x;
|
|
|
|
self.load_accumulator(val);
|
2014-11-02 19:23:38 +00:00
|
|
|
}
|
2014-10-25 23:04:52 +00:00
|
|
|
(instruction::TXS, instruction::UseImplied) => {
|
|
|
|
// Note that this is the only 'transfer' instruction that does
|
|
|
|
// NOT set the zero and negative flags. (Because the target
|
|
|
|
// is the stack pointer)
|
|
|
|
let val = self.registers.index_x;
|
|
|
|
self.registers.stack_pointer = StackPointer(val as u8);
|
2014-11-02 19:23:38 +00:00
|
|
|
}
|
2014-10-25 23:04:52 +00:00
|
|
|
(instruction::TYA, instruction::UseImplied) => {
|
|
|
|
let val = self.registers.index_y;
|
|
|
|
self.load_accumulator(val);
|
2014-11-02 19:23:38 +00:00
|
|
|
}
|
2014-10-25 23:04:52 +00:00
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
(instruction::NOP, instruction::UseImplied) => {
|
|
|
|
debug!("NOP instruction");
|
|
|
|
}
|
2014-10-04 20:33:42 +00:00
|
|
|
(_, _) => {
|
2014-11-02 19:23:38 +00:00
|
|
|
debug!("attempting to execute unimplemented or invalid \
|
|
|
|
instruction");
|
|
|
|
}
|
2014-10-01 22:02:45 +00:00
|
|
|
};
|
|
|
|
}
|
2014-10-04 20:33:42 +00:00
|
|
|
|
|
|
|
pub fn run(&mut self) {
|
2014-10-04 20:47:42 +00:00
|
|
|
loop {
|
|
|
|
if let Some(decoded_instr) = self.fetch_next_and_decode() {
|
2014-10-04 20:33:42 +00:00
|
|
|
self.execute_instruction(decoded_instr);
|
2014-10-04 20:47:42 +00:00
|
|
|
} else {
|
|
|
|
break
|
2014-10-04 20:33:42 +00:00
|
|
|
}
|
2014-10-04 20:47:42 +00:00
|
|
|
}
|
2014-10-04 20:33:42 +00:00
|
|
|
}
|
|
|
|
|
2014-11-02 20:40:34 +00:00
|
|
|
fn set_flags_from_i8(status: &mut Status, value: i8) {
|
2014-10-04 20:33:42 +00:00
|
|
|
let is_zero = value == 0;
|
|
|
|
let is_negative = value < 0;
|
|
|
|
|
|
|
|
status.set_with_mask(
|
2014-10-08 04:07:43 +00:00
|
|
|
PS_ZERO | PS_NEGATIVE,
|
2014-10-04 20:33:42 +00:00
|
|
|
Status::new(StatusArgs { zero: is_zero,
|
|
|
|
negative: is_negative,
|
|
|
|
..StatusArgs::none() } ));
|
|
|
|
}
|
|
|
|
|
2014-11-03 02:56:02 +00:00
|
|
|
fn shift_left_with_flags(p_val: &mut u8, status: &mut Status) {
|
|
|
|
let mask = 1 << 7;
|
|
|
|
let is_bit_7_set = (*p_val & mask) == mask;
|
|
|
|
let shifted = (*p_val & !(1 << 7)) << 1;
|
|
|
|
*p_val = shifted;
|
|
|
|
status.set_with_mask(
|
|
|
|
PS_CARRY,
|
|
|
|
Status::new(StatusArgs { carry: is_bit_7_set,
|
|
|
|
..StatusArgs::none() } ));
|
|
|
|
Machine::set_flags_from_i8(status, *p_val as i8);
|
|
|
|
}
|
|
|
|
|
2014-11-02 20:40:34 +00:00
|
|
|
fn shift_right_with_flags(p_val: &mut u8, status: &mut Status) {
|
2014-11-03 02:56:02 +00:00
|
|
|
let mask = 1;
|
|
|
|
let is_bit_0_set = (*p_val & mask) == mask;
|
2014-11-02 20:40:34 +00:00
|
|
|
*p_val = *p_val >> 1;
|
|
|
|
status.set_with_mask(
|
|
|
|
PS_CARRY,
|
2014-11-03 02:56:02 +00:00
|
|
|
Status::new(StatusArgs { carry: is_bit_0_set,
|
|
|
|
..StatusArgs::none() } ));
|
|
|
|
Machine::set_flags_from_i8(status, *p_val as i8);
|
|
|
|
}
|
|
|
|
|
|
|
|
fn rotate_left_with_flags(p_val: &mut u8, status: &mut Status) {
|
|
|
|
let is_carry_set = status.contains(PS_CARRY);
|
|
|
|
let mask = 1 << 7;
|
|
|
|
let is_bit_7_set = (*p_val & mask) == mask;
|
|
|
|
let shifted = (*p_val & !(1 << 7)) << 1;
|
|
|
|
*p_val = shifted + if is_carry_set { 1 } else { 0 };
|
|
|
|
status.set_with_mask(
|
|
|
|
PS_CARRY,
|
|
|
|
Status::new(StatusArgs { carry: is_bit_7_set,
|
|
|
|
..StatusArgs::none() } ));
|
|
|
|
Machine::set_flags_from_i8(status, *p_val as i8);
|
|
|
|
}
|
|
|
|
|
|
|
|
fn rotate_right_with_flags(p_val: &mut u8, status: &mut Status) {
|
|
|
|
let is_carry_set = status.contains(PS_CARRY);
|
|
|
|
let mask = 1;
|
|
|
|
let is_bit_0_set = (*p_val & mask) == mask;
|
|
|
|
let shifted = *p_val >> 1;
|
|
|
|
*p_val = shifted + if is_carry_set { 1 << 7 } else { 0 };
|
|
|
|
status.set_with_mask(
|
|
|
|
PS_CARRY,
|
|
|
|
Status::new(StatusArgs { carry: is_bit_0_set,
|
2014-11-02 20:40:34 +00:00
|
|
|
..StatusArgs::none() } ));
|
|
|
|
Machine::set_flags_from_i8(status, *p_val as i8);
|
|
|
|
}
|
|
|
|
|
|
|
|
fn set_i8_with_flags(mem: &mut i8, status: &mut Status, value: i8) {
|
|
|
|
*mem = value;
|
|
|
|
Machine::set_flags_from_i8(status, value);
|
|
|
|
}
|
|
|
|
|
2014-10-25 22:40:20 +00:00
|
|
|
fn load_x_register(&mut self, value: i8) {
|
2014-11-02 20:40:34 +00:00
|
|
|
Machine::set_i8_with_flags(&mut self.registers.index_x,
|
|
|
|
&mut self.registers.status,
|
|
|
|
value);
|
2014-10-04 20:33:42 +00:00
|
|
|
}
|
|
|
|
|
2014-10-25 22:40:20 +00:00
|
|
|
fn load_y_register(&mut self, value: i8) {
|
2014-11-02 20:40:34 +00:00
|
|
|
Machine::set_i8_with_flags(&mut self.registers.index_y,
|
|
|
|
&mut self.registers.status,
|
|
|
|
value);
|
2014-10-04 20:33:42 +00:00
|
|
|
}
|
|
|
|
|
2014-10-25 22:40:20 +00:00
|
|
|
fn load_accumulator(&mut self, value: i8) {
|
2014-11-02 20:40:34 +00:00
|
|
|
Machine::set_i8_with_flags(&mut self.registers.accumulator,
|
|
|
|
&mut self.registers.status,
|
|
|
|
value);
|
2014-10-04 20:33:42 +00:00
|
|
|
}
|
|
|
|
|
2014-10-25 22:40:20 +00:00
|
|
|
fn add_with_carry(&mut self, value: i8) {
|
2014-11-02 19:23:38 +00:00
|
|
|
if self.registers.status.contains(PS_DECIMAL_MODE) {
|
|
|
|
// TODO akeeton: Implement binary-coded decimal.
|
|
|
|
debug!("binary-coded decimal not implemented for add_with_carry");
|
|
|
|
} else {
|
|
|
|
let a_before: i8 = self.registers.accumulator;
|
|
|
|
let c_before: i8 = if self.registers.status.contains(PS_CARRY)
|
|
|
|
{ 1 } else { 0 };
|
|
|
|
let a_after: i8 = a_before + c_before + value;
|
2014-09-30 04:28:46 +00:00
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
debug_assert_eq!(a_after as u8, a_before as u8 + c_before as u8
|
|
|
|
+ value as u8);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
let did_carry = (a_after as u8) < (a_before as u8);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
let did_overflow =
|
|
|
|
(a_before < 0 && value < 0 && a_after >= 0)
|
|
|
|
|| (a_before > 0 && value > 0 && a_after <= 0);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
let mask = PS_CARRY | PS_OVERFLOW;
|
2014-09-30 04:28:46 +00:00
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
self.registers.status.set_with_mask(mask,
|
|
|
|
Status::new(StatusArgs { carry: did_carry,
|
|
|
|
overflow: did_overflow,
|
|
|
|
..StatusArgs::none() } ));
|
|
|
|
|
|
|
|
self.load_accumulator(a_after);
|
|
|
|
|
|
|
|
debug!("accumulator: {}", self.registers.accumulator);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2014-11-07 00:07:54 +00:00
|
|
|
fn and(&mut self, value: i8) {
|
|
|
|
let a_after = self.registers.accumulator & value;
|
|
|
|
self.load_accumulator(a_after);
|
|
|
|
}
|
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
// TODO: Implement binary-coded decimal
|
|
|
|
fn subtract_with_carry(&mut self, value: i8) {
|
|
|
|
if self.registers.status.contains(PS_DECIMAL_MODE) {
|
|
|
|
debug!("binary-coded decimal not implemented for \
|
|
|
|
subtract_with_carry");
|
|
|
|
} else {
|
|
|
|
// A - M - (1 - C)
|
|
|
|
|
|
|
|
// nc -- 'not carry'
|
|
|
|
let nc: i8 = if self.registers.status.contains(PS_CARRY)
|
|
|
|
{ 0 } else { 1 };
|
|
|
|
|
|
|
|
let a_before: i8 = self.registers.accumulator;
|
|
|
|
|
|
|
|
let a_after = a_before - value - nc;
|
2014-09-30 04:28:46 +00:00
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
// The carry flag is set on unsigned overflow.
|
|
|
|
let did_carry = (a_after as u8) > (a_before as u8);
|
2014-10-04 20:33:42 +00:00
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
// The overflow flag is set on two's-complement overflow.
|
|
|
|
//
|
|
|
|
// range of A is -128 to 127
|
|
|
|
// range of - M - (1 - C) is -128 to 128
|
|
|
|
// -(127 + 1) to -(-128 + 0)
|
|
|
|
//
|
|
|
|
let over = ((nc == 0 && value < 0) || (nc == 1 && value < -1))
|
|
|
|
&& a_before >= 0
|
|
|
|
&& a_after < 0;
|
|
|
|
|
|
|
|
let under = (a_before < 0) && (-value - nc < 0)
|
|
|
|
&& a_after >= 0;
|
|
|
|
|
|
|
|
let did_overflow = over || under;
|
|
|
|
|
|
|
|
let mask = PS_CARRY | PS_OVERFLOW;
|
|
|
|
|
|
|
|
self.registers.status.set_with_mask(mask,
|
|
|
|
Status::new(StatusArgs { carry: did_carry,
|
|
|
|
overflow: did_overflow,
|
|
|
|
..StatusArgs::none() } ));
|
|
|
|
|
|
|
|
self.load_accumulator(a_after);
|
|
|
|
}
|
2014-09-30 04:28:46 +00:00
|
|
|
}
|
2014-10-08 03:52:38 +00:00
|
|
|
|
2014-10-25 22:40:20 +00:00
|
|
|
fn decrement_memory(&mut self, addr: Address) {
|
2014-10-20 01:20:19 +00:00
|
|
|
let value_new = self.memory.get_byte(addr) - 1;
|
|
|
|
|
|
|
|
self.memory.set_byte(addr, value_new);
|
|
|
|
|
|
|
|
let is_negative = (value_new as i8) < 0;
|
|
|
|
let is_zero = value_new == 0;
|
|
|
|
|
|
|
|
self.registers.status.set_with_mask(
|
|
|
|
PS_NEGATIVE | PS_ZERO,
|
2014-11-02 19:23:38 +00:00
|
|
|
Status::new(StatusArgs { negative: is_negative,
|
|
|
|
zero: is_zero,
|
|
|
|
..StatusArgs::none() } ));
|
2014-10-20 01:20:19 +00:00
|
|
|
}
|
|
|
|
|
2014-10-25 22:40:20 +00:00
|
|
|
fn dec_x(&mut self) {
|
2014-10-17 00:05:41 +00:00
|
|
|
let val = self.registers.index_x;
|
|
|
|
self.load_x_register(val - 1);
|
2014-10-08 03:52:38 +00:00
|
|
|
}
|
2014-10-20 01:37:43 +00:00
|
|
|
|
2014-10-25 22:40:20 +00:00
|
|
|
fn jump(&mut self, addr: Address) {
|
2014-10-20 01:37:43 +00:00
|
|
|
self.registers.program_counter = addr;
|
|
|
|
}
|
2014-10-25 21:13:40 +00:00
|
|
|
|
2014-11-07 00:32:15 +00:00
|
|
|
fn branch_if_carry_clear(&mut self, addr: Address) {
|
|
|
|
if !self.registers.status.contains(PS_CARRY) {
|
|
|
|
self.registers.program_counter = addr;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2014-10-25 22:40:20 +00:00
|
|
|
fn branch_if_minus(&mut self, addr: Address) {
|
2014-10-17 02:02:18 +00:00
|
|
|
if self.registers.status.contains(PS_NEGATIVE) {
|
2014-10-13 23:39:17 +00:00
|
|
|
self.registers.program_counter = addr;
|
|
|
|
}
|
|
|
|
}
|
2014-11-03 02:56:02 +00:00
|
|
|
|
|
|
|
fn push_on_stack(&mut self, val: u8) {
|
|
|
|
let addr = self.registers.stack_pointer.to_address();
|
|
|
|
self.memory.set_byte(addr, val);
|
|
|
|
self.registers.stack_pointer.decrement();
|
|
|
|
}
|
|
|
|
|
|
|
|
fn pull_from_stack(&mut self) -> u8 {
|
|
|
|
let addr = self.registers.stack_pointer.to_address();
|
|
|
|
let out = self.memory.get_byte(addr);
|
|
|
|
self.registers.stack_pointer.increment();
|
|
|
|
out
|
|
|
|
}
|
2014-09-30 04:28:46 +00:00
|
|
|
}
|
|
|
|
|
2014-10-04 21:47:32 +00:00
|
|
|
impl std::fmt::Show for Machine {
|
|
|
|
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
|
2014-10-04 20:33:42 +00:00
|
|
|
write!(f, "Machine Dump:\n\nAccumulator: {}",
|
|
|
|
self.registers.accumulator)
|
2014-10-01 22:07:57 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2014-09-30 04:28:46 +00:00
|
|
|
#[test]
|
|
|
|
fn add_with_carry_test() {
|
|
|
|
let mut machine = Machine::new();
|
|
|
|
|
|
|
|
machine.add_with_carry(1);
|
|
|
|
assert_eq!(machine.registers.accumulator, 1);
|
2014-10-08 04:07:43 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
|
|
|
machine.add_with_carry(-1);
|
|
|
|
assert_eq!(machine.registers.accumulator, 0);
|
2014-10-08 04:07:43 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
|
|
|
machine.add_with_carry(1);
|
|
|
|
assert_eq!(machine.registers.accumulator, 2);
|
2014-10-08 04:07:43 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-10-20 01:37:43 +00:00
|
|
|
|
2014-09-30 04:28:46 +00:00
|
|
|
let mut machine = Machine::new();
|
|
|
|
|
|
|
|
machine.add_with_carry(127);
|
|
|
|
assert_eq!(machine.registers.accumulator, 127);
|
2014-10-08 04:07:43 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
|
|
|
machine.add_with_carry(-127);
|
|
|
|
assert_eq!(machine.registers.accumulator, 0);
|
2014-10-08 04:07:43 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
2014-10-08 04:07:43 +00:00
|
|
|
machine.registers.status.remove(PS_CARRY);
|
2014-09-30 04:28:46 +00:00
|
|
|
machine.add_with_carry(-128);
|
|
|
|
assert_eq!(machine.registers.accumulator, -128);
|
2014-10-08 04:07:43 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
|
|
|
machine.add_with_carry(127);
|
|
|
|
assert_eq!(machine.registers.accumulator, -1);
|
2014-10-08 04:07:43 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
|
|
|
let mut machine = Machine::new();
|
|
|
|
|
|
|
|
machine.add_with_carry(127);
|
|
|
|
assert_eq!(machine.registers.accumulator, 127);
|
2014-10-08 04:07:43 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-09-30 04:28:46 +00:00
|
|
|
|
|
|
|
machine.add_with_carry(1);
|
|
|
|
assert_eq!(machine.registers.accumulator, -128);
|
2014-10-08 04:07:43 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), true);
|
2014-09-30 04:28:46 +00:00
|
|
|
}
|
2014-10-08 03:52:38 +00:00
|
|
|
|
2014-11-06 23:58:09 +00:00
|
|
|
#[test]
|
|
|
|
fn and_test() {
|
|
|
|
let mut machine = Machine::new();
|
|
|
|
|
|
|
|
machine.registers.accumulator = 0;
|
2014-11-07 00:13:42 +00:00
|
|
|
machine.and(-1);
|
2014-11-06 23:58:09 +00:00
|
|
|
assert_eq!(machine.registers.accumulator, 0);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
|
2014-11-07 00:13:42 +00:00
|
|
|
machine.registers.accumulator = -1;
|
2014-11-06 23:58:09 +00:00
|
|
|
machine.and(0);
|
|
|
|
assert_eq!(machine.registers.accumulator, 0);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
|
2014-11-07 00:13:42 +00:00
|
|
|
machine.registers.accumulator = -1;
|
2014-11-06 23:58:09 +00:00
|
|
|
machine.and(0x0f);
|
|
|
|
assert_eq!(machine.registers.accumulator, 0x0f);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
|
2014-11-07 00:13:42 +00:00
|
|
|
machine.registers.accumulator = -1;
|
|
|
|
machine.and(-128);
|
|
|
|
assert_eq!(machine.registers.accumulator, -128);
|
2014-11-06 23:58:09 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
}
|
|
|
|
|
2014-11-02 19:23:38 +00:00
|
|
|
#[test]
|
|
|
|
fn subtract_with_carry_test() {
|
|
|
|
let mut machine = Machine::new();
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::SEC, instruction::UseImplied));
|
|
|
|
machine.registers.accumulator = 0;
|
|
|
|
|
|
|
|
machine.subtract_with_carry(1);
|
|
|
|
assert_eq!(machine.registers.accumulator, -1);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::SEC, instruction::UseImplied));
|
|
|
|
machine.registers.accumulator = -128;
|
|
|
|
machine.subtract_with_carry(1);
|
|
|
|
assert_eq!(machine.registers.accumulator, 127);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), true);
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::SEC, instruction::UseImplied));
|
|
|
|
machine.registers.accumulator = 127;
|
|
|
|
machine.subtract_with_carry(-1);
|
|
|
|
assert_eq!(machine.registers.accumulator, -128);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), true);
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::CLC, instruction::UseImplied));
|
|
|
|
machine.registers.accumulator = -64;
|
|
|
|
machine.subtract_with_carry(64);
|
|
|
|
assert_eq!(machine.registers.accumulator, 127);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), true);
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::SEC, instruction::UseImplied));
|
|
|
|
machine.registers.accumulator = 0;
|
|
|
|
machine.subtract_with_carry(-128);
|
|
|
|
assert_eq!(machine.registers.accumulator, -128);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), true);
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::CLC, instruction::UseImplied));
|
|
|
|
machine.registers.accumulator = 0;
|
|
|
|
machine.subtract_with_carry(127);
|
|
|
|
assert_eq!(machine.registers.accumulator, -128);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
|
|
|
}
|
|
|
|
|
2014-10-20 01:20:19 +00:00
|
|
|
#[test]
|
|
|
|
fn decrement_memory_test() {
|
|
|
|
let mut machine = Machine::new();
|
|
|
|
let addr = Address(0xA1B2);
|
|
|
|
|
|
|
|
machine.memory.set_byte(addr, 5);
|
|
|
|
|
|
|
|
machine.decrement_memory(addr);
|
|
|
|
assert_eq!(machine.memory.get_byte(addr), 4);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
|
|
|
|
machine.decrement_memory(addr);
|
|
|
|
assert_eq!(machine.memory.get_byte(addr), 3);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
|
|
|
|
machine.decrement_memory(addr);
|
|
|
|
machine.decrement_memory(addr);
|
|
|
|
machine.decrement_memory(addr);
|
|
|
|
assert_eq!(machine.memory.get_byte(addr), 0);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
|
|
|
|
machine.decrement_memory(addr);
|
|
|
|
assert_eq!(machine.memory.get_byte(addr) as i8, -1);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
}
|
|
|
|
|
2014-11-02 20:40:34 +00:00
|
|
|
#[test]
|
|
|
|
fn logical_shift_right_test() {
|
|
|
|
// Testing UseImplied version (which targets the accumulator) only, for now
|
|
|
|
|
|
|
|
let mut machine = Machine::new();
|
|
|
|
machine.execute_instruction((instruction::LDA,
|
|
|
|
instruction::UseImmediate(0)));
|
|
|
|
machine.execute_instruction((instruction::LSR,
|
|
|
|
instruction::UseImplied));
|
|
|
|
assert_eq!(machine.registers.accumulator, 0);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::LDA,
|
|
|
|
instruction::UseImmediate(1)));
|
|
|
|
machine.execute_instruction((instruction::LSR,
|
|
|
|
instruction::UseImplied));
|
|
|
|
assert_eq!(machine.registers.accumulator, 0);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::LDA,
|
|
|
|
instruction::UseImmediate(255)));
|
|
|
|
machine.execute_instruction((instruction::LSR,
|
|
|
|
instruction::UseImplied));
|
|
|
|
assert_eq!(machine.registers.accumulator, 0x7F);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::LDA,
|
|
|
|
instruction::UseImmediate(254)));
|
|
|
|
machine.execute_instruction((instruction::LSR,
|
|
|
|
instruction::UseImplied));
|
|
|
|
assert_eq!(machine.registers.accumulator, 0x7F);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
|
|
|
}
|
|
|
|
|
2014-10-08 03:52:38 +00:00
|
|
|
#[test]
|
|
|
|
fn dec_x_test() {
|
|
|
|
let mut machine = Machine::new();
|
|
|
|
|
|
|
|
machine.dec_x();
|
|
|
|
assert_eq!(machine.registers.index_x, -1);
|
2014-10-17 00:05:41 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-10-08 03:52:38 +00:00
|
|
|
|
|
|
|
machine.dec_x();
|
|
|
|
assert_eq!(machine.registers.index_x, -2);
|
2014-10-17 00:05:41 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-10-08 03:56:27 +00:00
|
|
|
|
|
|
|
machine.load_x_register(5);
|
|
|
|
machine.dec_x();
|
|
|
|
assert_eq!(machine.registers.index_x, 4);
|
2014-10-17 00:05:41 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-10-08 03:56:27 +00:00
|
|
|
|
|
|
|
machine.dec_x();
|
|
|
|
machine.dec_x();
|
|
|
|
machine.dec_x();
|
|
|
|
machine.dec_x();
|
|
|
|
|
|
|
|
assert_eq!(machine.registers.index_x, 0);
|
2014-10-17 00:05:41 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-10-08 03:56:27 +00:00
|
|
|
|
|
|
|
machine.dec_x();
|
|
|
|
assert_eq!(machine.registers.index_x, -1);
|
2014-10-17 00:05:41 +00:00
|
|
|
assert_eq!(machine.registers.status.contains(PS_CARRY), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_ZERO), false);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
|
|
|
|
assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
|
2014-10-08 03:52:38 +00:00
|
|
|
}
|
2014-10-20 01:37:43 +00:00
|
|
|
|
|
|
|
#[test]
|
|
|
|
fn jump_test() {
|
|
|
|
let mut machine = Machine::new();
|
|
|
|
let addr = Address(0xA1B1);
|
|
|
|
|
|
|
|
machine.jump(addr);
|
|
|
|
assert_eq!(machine.registers.program_counter, addr);
|
|
|
|
}
|
2014-10-25 21:13:40 +00:00
|
|
|
|
2014-11-07 00:30:05 +00:00
|
|
|
#[test]
|
|
|
|
fn branch_if_carry_clear_test() {
|
|
|
|
let mut machine = Machine::new();
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::SEC, instruction::UseImplied));
|
|
|
|
machine.branch_if_carry_clear(Address(0xABCD));
|
|
|
|
assert_eq!(machine.registers.program_counter, Address(0));
|
|
|
|
|
|
|
|
machine.execute_instruction((instruction::CLC, instruction::UseImplied));
|
|
|
|
machine.branch_if_carry_clear(Address(0xABCD));
|
|
|
|
assert_eq!(machine.registers.program_counter, Address(0xABCD));
|
|
|
|
}
|
|
|
|
|
2014-10-13 23:39:17 +00:00
|
|
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#[test]
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fn branch_if_minus_test() {
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{
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let mut machine = Machine::new();
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let registers_before = machine.registers;
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machine.branch_if_minus(Address(0xABCD));
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assert_eq!(machine.registers, registers_before);
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assert_eq!(machine.registers.program_counter, Address(0));
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}
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{
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let mut machine = Machine::new();
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2014-11-02 19:23:38 +00:00
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machine.registers.status.or(PS_NEGATIVE);
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2014-10-13 23:39:17 +00:00
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let registers_before = machine.registers;
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machine.branch_if_minus(Address(0xABCD));
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2014-10-17 00:00:53 +00:00
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assert_eq!(machine.registers.status, registers_before.status);
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2014-10-13 23:39:17 +00:00
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assert_eq!(machine.registers.program_counter, Address(0xABCD));
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}
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}
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