apple2js/test/cpu6502.spec.ts

import CPU6502, {
    CpuState,
    FLAVOR_ROCKWELL_65C02,
    flags
} from '../js/cpu6502';
import { TestMemory } from './util/memory';
import { bios, Program } from './util/bios';
import { toReadableState } from './util/cpu';

const DEFAULT_STATE: CpuState = {
    cycles: 0,
    s: flags.X,
    sp: 0xff,
    a: 0x00,
    x: 0x00,
    y: 0x00,
    pc: 0x0400
};

let memory;
let cpu: CPU6502;
let program;

function initState(initialState: Partial<CpuState>) {
    const state = {...DEFAULT_STATE, ...initialState};
    cpu.setState(state);
}

function expectState(initialState: CpuState, expectedState: Partial<CpuState>) {
    const state  = {...initialState, ...expectedState};
    expect(toReadableState(cpu.getState())).toEqual(toReadableState(state));
}

function initMemory(memAry: [page: number, off: number, data: number[]][]) {
    for (let idx = 0; idx < memAry.length; idx++) {
        const mem = memAry[idx];
        let page = mem[0];
        let off = mem[1];
        const data = mem[2];
        for (let jdx = 0; jdx < data.length; jdx++) {
            cpu.write(page, off++, data[jdx]);
            if (off > 0xff) {
                page++;
                off = 0;
            }
        }
    }
}

function expectMemory(expectAry: [page: number, off: number, data: number[]][]) {
    const memAry = [];
    for (let idx = 0; idx < expectAry.length; idx++) {
        const mem = expectAry[idx];
        let page = mem[0];
        let off = mem[1];
        const expectData = mem[2];
        const data = [];
        for (let jdx = 0; jdx < expectData.length; jdx++) {
            data.push(cpu.read(page, off++));
            if (off > 0xff) {
                page++;
                off = 0;
            }
        }
        memAry.push([mem[0], mem[1], data]);
    }
    expect(memAry).toEqual(expectAry);
}

function expectStack(expectAry: number[]) {
    const state = cpu.getState();
    expectMemory([[0x01, state.sp + 1, expectAry]]);
}

function testCode(code: number[], steps: number, setupState: Partial<CpuState>, expectedState: Partial<CpuState>) {
    const initialState = {...DEFAULT_STATE, ...setupState};
    const finalState =  { pc: initialState.pc + code.length, ...expectedState };

    program = new Program(0x04, code);
    cpu.addPageHandler(program);

    cpu.setState(initialState);
    cpu.stepN(steps);
    expectState(initialState, finalState);
}

describe('CPU6502', function() {
    beforeEach(function() {
        cpu = new CPU6502();
        memory = new TestMemory(4);

        cpu.addPageHandler(memory);
        cpu.addPageHandler(bios);
    });

    describe('#step functions', function() {
        const code = [0xEA, 0xEA, 0xEA, 0xEA, 0xEA, 0xEA, 0xEA, 0xEA];
        const initialState = {...DEFAULT_STATE};

        it('step', function() {
            cpu.setState(initialState);
            program = new Program(0x04, code);
            cpu.addPageHandler(program);
            cpu.step();
            expect(cpu.getState()).toEqual(
                { ...DEFAULT_STATE, pc: 0x401, cycles: 2 }
            );
            expect(cpu.getCycles()).toEqual(2);
        });

        it('step with callback', function() {
            const callback = jest.fn();
            cpu.setState(initialState);
            program = new Program(0x04, code);
            cpu.addPageHandler(program);
            cpu.step(callback);
            expect(cpu.getState()).toEqual({
                ...DEFAULT_STATE, pc: 0x401, cycles: 2,
            });
            expect(cpu.getCycles()).toEqual(2);
            expect(callback).toHaveBeenCalledTimes(1);
        });

        it('stepN', function() {
            cpu.setState(initialState);
            program = new Program(0x04, code);
            cpu.addPageHandler(program);
            cpu.stepN(4);
            expect(cpu.getState()).toEqual({
                ...DEFAULT_STATE, pc: 0x404, cycles: 8,
            });
            expect(cpu.getCycles()).toEqual(8);
        });

        it('stepN with callback', function() {
            const callback = jest.fn();
            cpu.setState(initialState);
            program = new Program(0x04, code);
            cpu.addPageHandler(program);
            cpu.stepN(4, callback);
            expect(cpu.getState()).toEqual({
                ...DEFAULT_STATE, pc: 0x404, cycles: 8,
            });
            expect(cpu.getCycles()).toEqual(8);
            expect(callback).toHaveBeenCalledTimes(4);
        });

        it('stepN with breakpoint', function() {
            const callback = jest.fn().mockReturnValue(true);
            cpu.setState(initialState);
            program = new Program(0x04, code);
            cpu.addPageHandler(program);
            cpu.stepN(4, callback);
            expect(cpu.getState()).toEqual({
                ...DEFAULT_STATE, pc: 0x401, cycles: 2,
            });
            expect(cpu.getCycles()).toEqual(2);
            expect(callback).toHaveBeenCalledTimes(1);
        });

        it('stepCycles', function() {
            cpu.setState(initialState);
            program = new Program(0x04, code);
            cpu.addPageHandler(program);
            cpu.stepCycles(4);
            expect(cpu.getState()).toEqual({
                ...DEFAULT_STATE, pc: 0x402, cycles: 4,
            });
            expect(cpu.getCycles()).toEqual(4);
        });

        it('stepCyclesDebug', function() {
            cpu.setState(initialState);
            program = new Program(0x04, code);
            cpu.addPageHandler(program);
            cpu.stepCyclesDebug(4);
            expect(cpu.getState()).toEqual({
                ...DEFAULT_STATE, pc: 0x402, cycles: 4,
            });
            expect(cpu.getCycles()).toEqual(4);
        });

        it('stepCyclesDebug with callback', function() {
            const callback = jest.fn();

            cpu.setState(initialState);
            program = new Program(0x04, code);
            cpu.addPageHandler(program);
            cpu.stepCyclesDebug(4, callback);
            expect(cpu.getState()).toEqual({
                ...DEFAULT_STATE, pc: 0x402, cycles: 4,
            });
            expect(cpu.getCycles()).toEqual(4);
            expect(callback).toHaveBeenCalledTimes(2);
        });

        it('stepCyclesDebug with breakpoint', function() {
            const callback = jest.fn().mockReturnValue(true);

            cpu.setState(initialState);
            program = new Program(0x04, code);
            cpu.addPageHandler(program);
            cpu.stepCyclesDebug(4, callback);
            expect(cpu.getState()).toEqual({
                ...DEFAULT_STATE, pc: 0x401, cycles: 2,
            });
            expect(cpu.getCycles()).toEqual(2);
            expect(callback).toHaveBeenCalledTimes(1);
        });
    });

    describe('#signals', function () {
        it('should reset', function () {
            cpu.reset();

            expectState(DEFAULT_STATE, {
                cycles: 2
            });
        });

        it('should irq', function () {
            cpu.irq();

            expectState(DEFAULT_STATE, {
                cycles: 5,
                s: flags.X | flags.I,
                sp: 0xfc,
                pc: 0xff00
            });
        });

        it('should not irq if I set', function () {
            initState({
                s: flags.X | flags.I
            });

            cpu.irq();

            expectState(DEFAULT_STATE, {
                s: flags.X | flags.I,
                pc: 0x400
            });
        });

        it('should nmi', function () {
            cpu.nmi();

            expectState(DEFAULT_STATE, {
                cycles: 5,
                s: flags.X | flags.I,
                sp: 0xfc,
                pc: 0xff00
            });
        });
    });

    describe('#misc', function () {
        it('should NOP', function () {
            testCode([0xEA], 1, {}, {
                cycles: 2
            });
        });

        it('should BRK', function () {
            testCode([0x00, 0x00], 1, {}, {
                cycles: 7,
                s: flags.X | flags.I,
                sp: 0xfc,
                pc: 0xff00
            });
        });

        it('should RTI', function () {
            initMemory([[0x01, 0xFD, [0xA0, 0x34, 0x12]]]);
            testCode([0x40], 1, {
                sp: 0xFC
            }, {
                cycles: 6,
                s: flags.X | flags.N,
                sp: 0xFF,
                pc: 0x1234
            });
        });
    });

    describe('#registers', function() {
        it('should LDA immediate', function () {
            testCode([0xA9, 0x44], 1, {}, {
                cycles: 2,
                a: 0x44
            });
        });

        it('should TAX', function () {
            testCode([0xAA], 1, {
                a: 0x44
            }, {
                cycles: 2,
                x: 0x44
            });
        });

        it('should TAY', function () {
            testCode([0xA8], 1, {
                a: 0x44
            }, {
                cycles: 2,
                y: 0x44
            });
        });

        it('should LDX immediate', function () {
            testCode([0xA2, 0x44], 1, {}, {
                cycles: 2,
                x: 0x44
            });
        });

        it('should TXA', function () {
            testCode([0x8A], 1, {
                x: 0x44
            }, {
                cycles: 2,
                a: 0x44
            });
        });

        it('should DEX', function () {
            testCode([0xCA], 1, {
                x: 0x44
            }, {
                cycles: 2,
                x: 0x43
            });
        });

        it('should INX', function () {
            testCode([0xE8], 1, {
                x: 0x44
            }, {
                cycles: 2,
                x: 0x45
            });
        });

        it('should LDY immediate', function () {
            testCode([0xA0, 0x44], 1, {}, {
                cycles: 2,
                y: 0x44
            });
        });

        it('should TYA', function () {
            testCode([0x98], 1, {
                y: 0x44
            }, {
                cycles: 2,
                a: 0x44
            });
        });

        it('should DEY', function () {
            testCode([0x88], 1, {
                y: 0x44
            }, {
                cycles: 2,
                y: 0x43
            });
        });

        it('should INY', function () {
            testCode([0xC8], 1, {
                y: 0x44
            }, {
                cycles: 2,
                y: 0x45
            });
        });
    });

    describe('#flags', function() {
        it('should SEC', function () {
            testCode([0x38], 1, {}, {
                cycles: 2,
                s: flags.X | flags.C
            });
        });

        it('should CLC', function () {
            testCode([0x18], 1, {
                s: flags.X | flags.C
            }, {
                cycles: 2,
                s: flags.X
            });
        });

        it('should SEI', function () {
            testCode([0x78], 1, {}, {
                cycles: 2,
                s: flags.X | flags.I
            });
        });

        it('should CLI', function () {
            testCode([0x58], 1, {
                s: flags.X | flags.I
            }, {
                cycles: 2,
                s: flags.X
            });
        });

        it('should CLV', function () {
            testCode([0xB8], 1, {
                s: flags.X | flags.V
            }, {
                cycles: 2,
                s: flags.X
            });
        });

        it('should SED', function () {
            testCode([0xF8], 1, {}, {
                cycles: 2,
                s: flags.X | flags.D
            });
        });

        it('should CLD', function () {
            testCode([0xD8], 1, {
                s: flags.X | flags.D
            }, {
                cycles: 2,
                s: flags.X
            });
        });
    });

    describe('#stack', function() {
        it('should TXS', function() {
            testCode([0x9A], 1, {
                x: 0x44
            }, {
                cycles: 2,
                sp: 0x44
            });
        });

        it('should TSX', function() {
            testCode([0xBA], 1, {
                sp: 0x44
            }, {
                cycles: 2,
                x: 0x44
            });
        });

        it('should PHA', function() {
            testCode([0x48], 1, {
                a: 0x44
            }, {
                cycles: 3,
                sp: 0xfe
            });
            expectStack([0x44]);
        });

        it('should PLA', function() {
            initMemory([[0x01, 0xff, [0x44]]]);
            testCode([0x68], 1, {
                sp: 0xfe
            }, {
                cycles: 4,
                a: 0x44,
                sp: 0xff
            });
        });

        it('should PHP', function() {
            testCode([0x08], 1, {
                s: flags.X | flags.N | flags.C
            }, {
                cycles: 3,
                sp: 0xfe
            });
            expectStack([flags.X | flags.B | flags.N | flags.C]);
        });

        it('should PLP', function() {
            initMemory([[0x01, 0xff, [flags.N | flags.C]]]);
            testCode([0x28], 1, {
                sp: 0xfe
            }, {
                cycles: 4,
                s: flags.X | flags.N | flags.C,
                sp: 0xff
            });
        });
    });

    describe('#jumps', function() {
        it('should JMP abs', function () {
            testCode([0x4C, 0x34, 0x12], 1, {}, {
                cycles: 3,
                pc: 0x1234
            });
        });

        it('should JMP (abs)', function () {
            initMemory([[0x03, 0x33, [0x34, 0x12]]]);
            testCode([0x6C, 0x33, 0x03], 1, {}, {
                cycles: 5,
                pc: 0x1234
            });
        });

        it('should JMP (abs) across page boundaries with bugs', function () {
            initMemory([[0x02, 0xFF, [0x34, 0x12]],
                [0x02, 0x00, [0xff]]]);
            testCode([0x6C, 0xFF, 0x02], 1, {}, {
                cycles: 5,
                pc: 0xFF34
            });
        });

        it('should JSR abs', function () {
            testCode([0x20, 0x34, 0x12], 1, {}, {
                cycles: 6,
                sp: 0xFD,
                pc: 0x1234
            });
            expectStack([0x02, 0x04]);
        });

        it('should RTS', function () {
            initMemory([[0x01, 0xFE, [0x34, 0x12]]]);
            testCode([0x60], 1, {
                sp: 0xFD
            }, {
                cycles: 6,
                sp: 0xFF,
                pc: 0x1235
            });
        });
    });

    describe('#branches', function() {
        // ********** bcs
        it('should BCS forward', function () {
            testCode([0xB0, 0x7F], 1, {
                s: flags.X | flags.C
            }, {
                cycles: 3,
                pc: 0x0481
            });
        });

        it('should BCS backward', function () {
            testCode([0xB0, 0xff], 1, {
                s: flags.X | flags.C
            }, {
                cycles: 3,
                pc: 0x0401
            });
        });

        it('should BCS across pages with an extra cycle', function () {
            testCode([0xB0, 0xfd], 1, {
                s: flags.X | flags.C
            }, {
                cycles: 4,
                pc: 0x03FF
            });
        });

        it('should not BCS if carry clear', function () {
            testCode([0xB0, 0xfd], 1, {}, {
                cycles: 2,
                pc: 0x0402
            });
        });

        it('should BCC forward', function () {
            testCode([0x90, 0x7F], 1, {}, {
                cycles: 3,
                pc: 0x0481
            });
        });

        it('should BCC backward', function () {
            testCode([0x90, 0xff], 1, {}, {
                cycles: 3,
                pc: 0x0401
            });
        });

        it('should BCC across pages with an extra cycle', function () {
            testCode([0x90, 0xfd], 1, {}, {
                cycles: 4,
                pc: 0x03FF
            });
        });

        it('should not BCC if carry set', function () {
            testCode([0x90, 0xfd], 1, {
                s: flags.X | flags.C
            }, {
                cycles: 2,
                pc: 0x0402
            });
        });
    });

    describe('#read memory', function() {
        // ********** zp
        it('should LDY zp', function () {
            initMemory([[0x00, 0x33, [0x44]]]);
            testCode([0xA4, 0x33], 1, {}, {
                cycles: 3,
                y: 0x44
            });
        });

        it('should LDA zp', function () {
            initMemory([[0x00, 0x33, [0x44]]]);
            testCode([0xA5, 0x33], 1, {}, {
                cycles: 3,
                a: 0x44
            });
        });

        it('should LDX zp', function () {
            initMemory([[0x00, 0x33, [0x44]]]);
            testCode([0xA6, 0x33], 1, {}, {
                cycles: 3,
                x: 0x44
            });
        });

        // ********** zp,x
        it('should LDY zp,x', function () {
            initMemory([[0x00, 0x36, [0x44]]]);
            testCode([0xB4, 0x33], 1, {
                x: 3
            }, {
                cycles: 4,
                y: 0x44
            });
        });

        it('should LDA zp,x', function () {
            initMemory([[0x00, 0x36, [0x44]]]);
            testCode([0xB5, 0x33], 1, {
                x: 3
            }, {
                cycles: 4,
                a: 0x44
            });
        });

        // ********** zp,y
        it('should LDX zp,y', function () {
            initMemory([[0x00, 0x36, [0x44]]]);
            testCode([0xB6, 0x33], 1, {
                y: 3
            }, {
                cycles: 4,
                x: 0x44
            });
        });

        // ********** (zp,x)
        it('should LDA (zp,x)', function () {
            initMemory([
                [0x00, 0x36, [0x33, 0x03]],
                [0x03, 0x33, [0x44]]]
            );
            testCode([0xA1, 0x33], 1, {
                x: 3
            }, {
                cycles: 6,
                a: 0x44
            });
        });

        // ********** (zp),y
        it('should LDA (zp),y', function () {
            initMemory([
                [0x00, 0x33, [0x33, 0x03]],
                [0x03, 0x36, [0x44]]
            ]);
            testCode([0xB1, 0x33], 1, {
                y: 3
            }, {
                cycles: 5,
                a: 0x44
            });
        });

        // ********** (zp),y
        it('should LDA (zp),y with an extra cycle on page cross', function () {
            initMemory([
                [0x00, 0x33, [0x33, 0x02]],
                [0x03, 0x32, [0x44]]
            ]);
            testCode([0xB1, 0x33], 1, {
                y: 0xff
            }, {
                cycles: 6,
                a: 0x44
            });
        });

        // ********** abs
        it('should LDY abs', function () {
            initMemory([[0x03, 0x33, [0x44]]]);
            testCode([0xAC, 0x33, 0x03], 1, {}, {
                cycles: 4,
                y: 0x44
            });
        });

        it('should LDA abs', function () {
            initMemory([[0x03, 0x33, [0x44]]]);
            testCode([0xAD, 0x33, 0x03], 1, {}, {
                cycles: 4,
                a: 0x44
            });
        });

        it('should LDX abs', function () {
            initMemory([[0x03, 0x33, [0x44]]]);
            testCode([0xAE, 0x33, 0x03], 1, {}, {
                cycles: 4,
                x: 0x44
            });
        });

        // ********** abs, x
        it('should LDY abs,x', function () {
            initMemory([[0x03, 0x36, [0x44]]]);
            testCode([0xBC, 0x33, 0x03], 1, {
                x: 3
            }, {
                cycles: 4,
                y: 0x44
            });
        });

        it('should LDA abs,x', function () {
            initMemory([[0x03, 0x36, [0x44]]]);
            testCode([0xBD, 0x33, 0x03], 1, {
                x: 3
            }, {
                cycles: 4,
                a: 0x44
            });
        });

        it('should LDY abs,x with extra cycle on page cross', function () {
            initMemory([[0x03, 0x32, [0x44]]]);
            testCode([0xBC, 0x33, 0x02], 1, {
                x: 0xff
            }, {
                cycles: 5,
                y: 0x44
            });
        });

        it('should LDA abs,x with extra cycle on page cross', function () {
            initMemory([[0x03, 0x32, [0x44]]]);
            testCode([0xBD, 0x33, 0x02], 1, {
                x: 0xff
            }, {
                cycles: 5,
                a: 0x44
            });
        });

        // ********** abs, y
        it('should LDX abs,y', function () {
            initMemory([[0x03, 0x36, [0x44]]]);
            testCode([0xBE, 0x33, 0x03], 1, {
                y: 3
            }, {
                cycles: 4,
                x: 0x44
            });
        });

        it('should LDX abs,y with extra cycle on page cross', function () {
            initMemory([[0x03, 0x32, [0x44]]]);
            testCode([0xBE, 0x33, 0x02], 1, {
                y: 0xff
            }, {
                cycles: 5,
                x: 0x44
            });
        });
    });

    describe('#write memory', function() {
        // ********** zp
        it('should STY zp', function () {
            testCode([0x84, 0x33], 1, {
                y: 0x44
            }, {
                cycles: 3
            });
            expectMemory([[0x00, 0x33, [0x44]]]);
        });

        it('should STA zp', function () {
            testCode([0x85, 0x33], 1, {
                a: 0x44
            }, {
                cycles: 3
            });
            expectMemory([[0x00, 0x33, [0x44]]]);
        });

        it('should STX zp', function () {
            testCode([0x86, 0x33], 1, {
                x: 0x44
            }, {
                cycles: 3
            });
            expectMemory([[0x00, 0x33, [0x44]]]);
        });

        // ********** zp,x
        it('should STY zp,x', function () {
            testCode([0x94, 0x33], 1, {
                x: 3,
                y: 0x44
            }, {
                cycles: 4
            });
            expectMemory([[0x00, 0x36, [0x44]]]);
        });

        it('should STA zp,x', function () {
            testCode([0x95, 0x33], 1, {
                a: 0x44,
                x: 3
            }, {
                cycles: 4
            });
            expectMemory([[0x00, 0x36, [0x44]]]);
        });

        // ********** zp,y
        it('should STX zp,y', function () {
            testCode([0x96, 0x33], 1, {
                x: 0x44,
                y: 3
            }, {
                cycles: 4
            });
            expectMemory([[0x00, 0x36, [0x44]]]);
        });

        // ********** (zp,x)
        it('should STA (zp,x)', function () {
            initMemory([[0x00, 0x36, [0x33, 0x03]]]);
            testCode([0x81, 0x33], 1, {
                a: 0x44,
                x: 3
            }, {
                cycles: 6
            });
            expectMemory([[0x03, 0x33, [0x44]]]);
        });

        // ********** (zp),y
        it('should STA (zp),y', function () {
            initMemory([[0x00, 0x33, [0x33, 0x03]]]);
            testCode([0x91, 0x33], 1, {
                a: 0x44,
                y: 3
            }, {
                cycles: 6
            });
            expectMemory([[0x03, 0x36, [0x44]]]);
        });

        // ********** abs
        it('should STY abs', function () {
            testCode([0x8C, 0x33, 0x03], 1, {
                y: 0x44
            }, {
                cycles: 4
            });
            expectMemory([[0x03, 0x33, [0x44]]]);
        });

        it('should STA abs', function () {
            testCode([0x8D, 0x33, 0x03], 1, {
                a: 0x44
            }, {
                cycles: 4
            });
            expectMemory([[0x03, 0x33, [0x44]]]);
        });

        it('should STX abs', function () {
            testCode([0x8E, 0x33, 0x03], 1, {
                x: 0x44
            }, {
                cycles: 4
            });
            expectMemory([[0x03, 0x33, [0x44]]]);
        });

        // ********** abs, x
        it('should STA abs,x', function () {
            testCode([0x9D, 0x33, 0x03], 1, {
                a: 0x44,
                x: 0x03
            }, {
                cycles: 5
            });
            expectMemory([[0x03, 0x36, [0x44]]]);
        });

        it('should STA abs,x with no extra cycle on page cross', function () {
            testCode([0x9D, 0x33, 0x02], 1, {
                a: 0x44,
                x: 0xff
            }, {
                cycles: 5,
                pc: 0x0403
            });
            expectMemory([[0x03, 0x32, [0x44]]]);
        });

        // ********** abs, y
        it('should STA abs,y', function () {
            testCode([0x99, 0x33, 0x03], 1, {
                a: 0x44,
                y: 0x03
            }, {
                cycles: 5
            });
            expectMemory([[0x03, 0x36, [0x44]]]);
        });

        it('should STA abs,y with no extra cycle on page cross', function () {
            testCode([0x99, 0x33, 0x02], 1, {
                a: 0x44,
                y: 0xff
            }, {
                cycles: 5
            });
            expectMemory([[0x03, 0x32, [0x44]]]);
        });
    });

    describe('#bit operations', function() {
        // ********** ASL
        it('should ASL A', function () {
            testCode([0x0A], 1, {
                a: 0x55
            }, {
                cycles: 2,
                a: 0xAA,
                s: flags.X | flags.N
            });
        });

        it('should ASL A with carry out', function () {
            testCode([0x0A], 1, {
                a: 0xAA
            }, {
                cycles: 2,
                a: 0x54,
                s: flags.X | flags.C
            });
        });

        it('should ASL abs', function () {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x0E, 0x33, 0x03], 1, {
            }, {
                cycles: 6,
                s: flags.X | flags.N
            });
            expectMemory([[0x03, 0x33, [0xAA]]]);
        });

        it('should ASL abs with carry out', function () {
            initMemory([[0x03, 0x33, [0xAA]]]);
            testCode([0x0E, 0x33, 0x03], 1, {
            }, {
                cycles: 6,
                s: flags.X | flags.C
            });
            expectMemory([[0x03, 0x33, [0x54]]]);
        });

        // ********** ROL
        it('should ROL A', function () {
            testCode([0x2A], 1, {
                a: 0x55
            }, {
                cycles: 2,
                a: 0xAA,
                s: flags.X | flags.N
            });
        });

        it('should ROL A with carry out', function () {
            testCode([0x2A], 1, {
                a: 0xAA
            }, {
                cycles: 2,
                a: 0x54,
                s: flags.X | flags.C
            });
        });

        it('should ROL A with carry in', function () {
            testCode([0x2A], 1, {
                s: flags.X | flags.C,
                a: 0xAA
            }, {
                cycles: 2,
                a: 0x55,
                s: flags.X | flags.C
            });
        });

        it('should ROL abs', function () {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x2E, 0x33, 0x03], 1, {
            }, {
                cycles: 6,
                s: flags.X | flags.N
            });
            expectMemory([[0x03, 0x33, [0xAA]]]);
        });

        it('should ROL abs with carry out', function () {
            initMemory([[0x03, 0x33, [0xAA]]]);
            testCode([0x2E, 0x33, 0x03], 1, {
            }, {
                cycles: 6,
                s: flags.X | flags.C
            });
            expectMemory([[0x03, 0x33, [0x54]]]);
        });

        it('should ROL abs with carry in', function () {
            initMemory([[0x03, 0x33, [0xAA]]]);
            testCode([0x2E, 0x33, 0x03], 1, {
                s: flags.X | flags.C
            }, {
                cycles: 6,
                s: flags.X | flags.C
            });
            expectMemory([[0x03, 0x33, [0x55]]]);
        });

        // ********** LSR
        it('should LSR A', function () {
            testCode([0x4A], 1, {
                a: 0xAA
            }, {
                cycles: 2,
                a: 0x55
            });
        });

        it('should LSR A with carry out', function () {
            testCode([0x4A], 1, {
                a: 0x55
            }, {
                cycles: 2,
                a: 0x2A,
                s: flags.X | flags.C
            });
        });

        it('should LSR abs', function () {
            initMemory([[0x03, 0x33, [0xAA]]]);
            testCode([0x4E, 0x33, 0x03], 1, {
            }, {
                cycles: 6
            });
            expectMemory([[0x03, 0x33, [0x55]]]);
        });

        it('should LSR abs with carry out', function () {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x4E, 0x33, 0x03], 1, {
            }, {
                cycles: 6,
                s: flags.X | flags.C
            });
            expectMemory([[0x03, 0x33, [0x2A]]]);
        });

        // ********** ROR
        it('should ROR A', function () {
            testCode([0x6A], 1, {
                a: 0xAA
            }, {
                cycles: 2,
                a: 0x55
            });
        });

        it('should ROR A with carry out', function () {
            testCode([0x6A], 1, {
                a: 0x55
            }, {
                cycles: 2,
                s: flags.X | flags.C,
                a: 0x2A
            });
        });

        it('should ROR A with carry in', function () {
            testCode([0x6A], 1, {
                s: flags.X | flags.C,
                a: 0x55
            }, {
                cycles: 2,
                s: flags.X | flags.C | flags.N,
                a: 0xAA
            });
        });

        it('should ROR abs', function () {
            initMemory([[0x03, 0x33, [0xAA]]]);
            testCode([0x6E, 0x33, 0x03], 1, {
            }, {
                cycles: 6
            });
            expectMemory([[0x03, 0x33, [0x55]]]);
        });

        it('should ROR abs with carry out', function () {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x6E, 0x33, 0x03], 1, {
            }, {
                cycles: 6,
                s: flags.X | flags.C
            });
            expectMemory([[0x03, 0x33, [0x2A]]]);
        });

        it('should ROR abs with carry in', function () {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x6E, 0x33, 0x03], 1, {
                s: flags.X | flags.C
            }, {
                cycles: 6,
                s: flags.X | flags.C | flags.N
            });
            expectMemory([[0x03, 0x33, [0xAA]]]);
        });

        it('should AND', function() {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x2D, 0x33, 0x03], 1, {
                a: 0xA5
            }, {
                cycles: 4,
                a: 0x05
            });
        });

        it('should ORA', function() {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x0D, 0x33, 0x03], 1, {
                a: 0xA0
            }, {
                cycles: 4,
                s: flags.X | flags.N,
                a: 0xF5
            });
        });

        it('should EOR', function() {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x4D, 0x33, 0x03], 1, {
                a: 0xA5
            }, {
                cycles: 4,
                s: flags.X | flags.N,
                a: 0xF0
            });
        });

        it('should BIT zp', function() {
            initMemory([[0x00, 0x33, [0x55]]]);
            testCode([0x24, 0x33], 1, {
                a: 0x55
            }, {
                cycles: 3,
                s: flags.X | flags.V
            });
        });

        it('should BIT abs', function() {
            initMemory([[0x03, 0x33, [0xAA]]]);
            testCode([0x2C, 0x33, 0x03], 1, {
            }, {
                cycles: 4,
                s: flags.X | flags.N | flags.Z
            });
        });
    });

    describe('#math', function() {
        // ********** ADC
        it('should ADC', function () {
            testCode([0x69, 0x55], 1, {
                a: 0x23
            }, {
                cycles: 2,
                a: 0x78,
                s: flags.X
            });
        });

        it('should ADC with carry in', function () {
            testCode([0x69, 0x55], 1, {
                a: 0x23,
                s: flags.X | flags.C
            }, {
                cycles: 2,
                a: 0x79,
                s: flags.X
            });
        });

        it('should ADC with overflow out', function () {
            testCode([0x69, 0x55], 1, {
                a: 0x2B
            }, {
                cycles: 2,
                a: 0x80,
                s: flags.X | flags.N | flags.V
            });
        });

        it('should ADC with carry out', function () {
            testCode([0x69, 0x55], 1, {
                a: 0xBB
            }, {
                cycles: 2,
                a: 0x10,
                s: flags.X | flags.C
            });
        });

        // ********** ADC BCD
        it('should ADC BCD', function () {
            testCode([0x69, 0x16], 1, {
                s: flags.X | flags.D,
                a: 0x25
            }, {
                cycles: 2,
                s: flags.X | flags.D,
                a: 0x41
            });
        });

        it('should ADC BCD with carry in', function () {
            testCode([0x69, 0x55], 1, {
                s: flags.X | flags.D | flags.C,
                a: 0x23
            }, {
                cycles: 2,
                s: flags.X | flags.D,
                a: 0x79
            });
        });

        it('should ADC BCD with carry out', function () {
            testCode([0x69, 0x10], 1, {
                s: flags.X | flags.D,
                a: 0x91
            }, {
                cycles: 2,
                a: 0x01,
                s: flags.X | flags.N | flags.D |  flags.C
            });
        });

        // ********** SBC
        it('should SBC', function () {
            testCode([0xE9, 0x23], 1, {
                s: flags.X | flags.C,
                a: 0x55
            }, {
                cycles: 2,
                a: 0x32,
                s: flags.X | flags.C
            });
        });

        it('should SBC with borrow in', function () {
            testCode([0xE9, 0x23], 1, {
                s: flags.X,
                a: 0x55
            }, {
                cycles: 2,
                a: 0x31,
                s: flags.X | flags.C
            });
        });

        it('should SBC with borrow out', function () {
            testCode([0xE9, 0x55], 1, {
                s: flags.X | flags.C,
                a: 0x23
            }, {
                cycles: 2,
                a: 0xCE,
                s: flags.X | flags.N
            });
        });

        it('should SBC with overflow out', function () {
            testCode([0xE9, 0x7F], 1, {
                s: flags.X | flags.C,
                a: 0xAF
            }, {
                cycles: 2,
                a: 0x30,
                s: flags.X | flags.V | flags.C
            });
        });

        // ********** SBC BCD
        it('should SBC BCD', function () {
            testCode([0xE9, 0x23], 1, {
                s: flags.X | flags.D | flags.C,
                a: 0x55
            }, {
                cycles: 2,
                a: 0x32,
                s: flags.X | flags.D | flags.C
            });
        });

        it('should SBC BCD with borrow in', function () {
            testCode([0xE9, 0x23], 1, {
                s: flags.X | flags.D,
                a: 0x55
            }, {
                cycles: 2,
                a: 0x31,
                s: flags.X | flags.D | flags.C
            });
        });

        it('should SBC BCD with borrow out', function () {
            testCode([0xE9, 0x55], 1, {
                s: flags.X | flags.D | flags.C,
                a: 0x23
            }, {
                cycles: 2,
                a: 0x68,
                s: flags.X | flags.N | flags.D
            });
        });

        // ********** INC
        it('should INC zp', function() {
            initMemory([[0x00, 0x33, [0x44]]]);
            testCode([0xE6, 0x33], 1, {
            }, {
                cycles: 5
            });
            expectMemory([[0x00, 0x33, [0x45]]]);
        });

        it('should INC zp,x', function() {
            initMemory([[0x00, 0x043, [0x44]]]);
            testCode([0xF6, 0x33], 1, {
                x: 0x10
            }, {
                cycles: 6
            });
            expectMemory([[0x00, 0x43, [0x45]]]);
        });

        it('should INC abs', function() {
            initMemory([[0x03, 0x33, [0x44]]]);
            testCode([0xEE, 0x33, 0x03], 1, {
            }, {
                cycles: 6
            });
            expectMemory([[0x03, 0x33, [0x45]]]);
        });

        it('should INC abs,x', function() {
            initMemory([[0x03, 0x043, [0x44]]]);
            testCode([0xFE, 0x33, 0x03], 1, {
                x: 0x10
            }, {
                cycles: 7
            });
            expectMemory([[0x03, 0x43, [0x45]]]);
        });

        // ********** DEC
        it('should DEC zp', function() {
            initMemory([[0x00, 0x33, [0x44]]]);
            testCode([0xC6, 0x33], 1, {
            }, {
                cycles: 5
            });
            expectMemory([[0x00, 0x33, [0x43]]]);
        });

        it('should DEC zp,x', function() {
            initMemory([[0x00, 0x043, [0x44]]]);
            testCode([0xD6, 0x33], 1, {
                x: 0x10
            }, {
                cycles: 6
            });
            expectMemory([[0x00, 0x43, [0x43]]]);
        });

        it('should DEC abs', function() {
            initMemory([[0x03, 0x33, [0x44]]]);
            testCode([0xCE, 0x33, 0x03], 1, {
            }, {
                cycles: 6
            });
            expectMemory([[0x03, 0x33, [0x43]]]);
        });

        it('should DEC abs,x', function() {
            initMemory([[0x03, 0x043, [0x44]]]);
            testCode([0xDE, 0x33, 0x03], 1, {
                x: 0x10
            }, {
                cycles: 7
            });
            expectMemory([[0x03, 0x43, [0x43]]]);
        });
    });

    describe('#comparison', function() {
        // ********** CMP
        it('should CMP less than', function() {
            testCode([0xc9, 0x44], 1, {
                a: 0x33
            }, {
                cycles: 2,
                s: flags.X | flags.N
            });
        });

        it('should CMP equal', function() {
            testCode([0xc9, 0x44], 1, {
                a: 0x44
            }, {
                cycles: 2,
                s: flags.X | flags.Z | flags.C
            });
        });

        it('should CMP greater than', function() {
            testCode([0xc9, 0x44], 1, {
                a: 0x55
            }, {
                cycles: 2,
                s: flags.X | flags.C
            });
        });

        // ********** CPX
        it('should CPX less than', function() {
            testCode([0xE0, 0x44], 1, {
                x: 0x33
            }, {
                cycles: 2,
                s: flags.X | flags.N
            });
        });

        it('should CPX equal', function() {
            testCode([0xE0, 0x44], 1, {
                x: 0x44
            }, {
                cycles: 2,
                s: flags.X | flags.Z | flags.C
            });
        });

        it('should CPX greater than', function() {
            testCode([0xE0, 0x44], 1, {
                x: 0x55
            }, {
                cycles: 2,
                s: flags.X | flags.C
            });
        });

        // ********** CPY
        it('should CPY less than', function() {
            testCode([0xE0, 0x44], 1, {
                y: 0x33
            }, {
                cycles: 2,
                s: flags.X | flags.N
            });
        });

        it('should CPY equal', function() {
            testCode([0xc0, 0x44], 1, {
                y: 0x44
            }, {
                cycles: 2,
                s: flags.X | flags.Z | flags.C
            });
        });

        it('should CPY greater than', function() {
            testCode([0xc0, 0x44], 1, {
                y: 0x55
            }, {
                cycles: 2,
                s: flags.X | flags.C
            });
        });
    });
});

describe('65c02', function() {
    beforeEach(function() {
        cpu = new CPU6502({ flavor: FLAVOR_ROCKWELL_65C02 });
        memory = new TestMemory(4);

        cpu.addPageHandler(memory);
        cpu.addPageHandler(bios);
    });

    describe('#signals', function() {
        it('should clear D on IRQ', function() {
            initState({
                s: flags.X | flags.D
            });

            cpu.irq();

            expectState(DEFAULT_STATE, {
                cycles: 5,
                s: flags.X | flags.I,
                sp: 0xfc,
                pc: 0xff00
            });
        });

        it('should clear D on NMI', function() {
            initState({
                s: flags.X | flags.D
            });

            cpu.nmi();

            expectState(DEFAULT_STATE, {
                cycles: 5,
                s: flags.X | flags.I,
                sp: 0xfc,
                pc: 0xff00
            });
        });

        it('should clear D on BRK', function () {
            testCode([0x00, 0x00], 1, {
                s: flags.X | flags.D
            }, {
                cycles: 7,
                s: flags.X | flags.I,
                sp: 0xfc,
                pc: 0xff00
            });
        });
    });

    describe('#stack', function() {
        it('should PHX', function() {
            testCode([0xDA], 1, {
                x: 0x44
            }, {
                cycles: 3,
                sp: 0xfe
            });
            expectStack([0x44]);
        });

        it('should PLX', function() {
            initMemory([[0x01, 0xff, [0x44]]]);
            testCode([0xFA], 1, {
                sp: 0xfe
            }, {
                cycles: 4,
                x: 0x44,
                sp: 0xff
            });
        });

        it('should PHY', function() {
            testCode([0x5A], 1, {
                y: 0x44
            }, {
                cycles: 3,
                sp: 0xfe
            });
            expectStack([0x44]);
        });

        it('should PLY', function() {
            initMemory([[0x01, 0xff, [0x44]]]);
            testCode([0x7A], 1, {
                sp: 0xfe
            }, {
                cycles: 4,
                y: 0x44,
                sp: 0xff
            });
        });

    });

    describe('#jumps', function() {
        it('should JMP (abs)', function () {
            initMemory([[0x03, 0x33, [0x34, 0x12]]]);
            testCode([0x6C, 0x33, 0x03], 1, {}, {
                cycles: 6,
                pc: 0x1234
            });
        });

        it('should JMP (abs) across page boundries without bugs', function () {
            initMemory([[0x02, 0xFF, [0x34, 0x12]],
                [0x02, 0x00, [0xff]]]);
            testCode([0x6C, 0xFF, 0x02], 1, {}, {
                cycles: 6,
                pc: 0x1234
            });
        });

        it('should JMP (abs, x)', function () {
            initMemory([[0x03, 0x43, [0x34, 0x12]]]);
            testCode([0x7C, 0x33, 0x03], 1, {
                x: 0x10
            }, {
                cycles: 6,
                pc: 0x1234
            });
        });
    });

    describe('#other addressing mode fixes', function () {
        it('should INC abs,x', function() {
            initMemory([[0x03, 0x043, [0x44]]]);
            testCode([0xFE, 0x33, 0x03], 1, {
                x: 0x10
            }, {
                cycles: 7
            });
            expectMemory([[0x03, 0x43, [0x45]]]);
        });
    });

    describe('#branches', function() {
        it('should BRA forward', function () {
            testCode([0x80, 0x7F], 1, {}, {
                cycles: 3,
                pc: 0x0481
            });
        });

        it('should BRA backward', function () {
            testCode([0x80, 0xFF], 1, {}, {
                cycles: 3,
                pc: 0x0401
            });
        });
    });

    describe('#read memory', function() {
        // ********** (zp)
        it('should LDA (zp)', function () {
            initMemory([[0x00, 0x33, [0x33,0x03]],
                [0x03, 0x33, [0x44]]]);
            testCode([0xB2, 0x33], 1, {}, {
                cycles: 5,
                a: 0x44
            });
        });
    });

    describe('#write memory', function() {
        // ********** (zp)
        it('should STA (zp)', function () {
            initMemory([[0x00, 0x33, [0x33, 0x03]]]);
            testCode([0x92, 0x33], 1, {
                a: 0x44
            }, {
                cycles: 5
            });
            expectMemory([[0x03, 0x33, [0x44]]]);
        });

        it('should STZ abs', function () {
            initMemory([[0x03, 0x33, [0x44]]]);
            testCode([0x9C, 0x33, 0x03], 1, {
                a: 0x44
            }, {
                cycles: 4
            });
            expectMemory([[0x03, 0x33, [0x00]]]);
        });
    });

    describe('#logical operators', function() {
        it('should BIT imm and effect other flags', function() {
            testCode([0x89, 0x33], 1, {
                s: flags.X | flags.N,
                a: 0x44
            }, {
                cycles: 2,
                s: flags.X | flags.Z | flags.N
            });
        });

        it('should BIT imm', function() {
            testCode([0x89, 0x33], 1, {
                a: 0x03
            }, {
                cycles: 2,
                s: flags.X
            });
        });

        // ******** TRB
        it('should TRB zp', function() {
            initMemory([[0x00, 0x33, [0x55]]]);
            testCode([0x14, 0x33], 1, {
                a: 0xA5
            }, {
                cycles: 5
            });
            expectMemory([[0x00, 0x33, [0x50]]]);
        });

        it('should TRB abs', function() {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x1C, 0x33, 0x03], 1, {
                a: 0xAA
            }, {
                cycles: 6,
                s: flags.X | flags.Z
            });
            expectMemory([[0x00, 0x33, [0x00]]]);
        });

        // ******** TSB
        it('should TSB zp', function() {
            initMemory([[0x00, 0x33, [0x55]]]);
            testCode([0x04, 0x33], 1, {
                a: 0xA5
            }, {
                cycles: 5
            });
            expectMemory([[0x00, 0x33, [0xF5]]]);
        });

        it('should TSB abs', function() {
            initMemory([[0x03, 0x33, [0x55]]]);
            testCode([0x0C, 0x33, 0x03], 1, {
                a: 0xAA
            }, {
                cycles: 6,
                s: flags.X | flags.Z
            });
            expectMemory([[0x03, 0x33, [0xFF]]]);
        });
    });

    describe('Branch bit set/reset', function () {
        // ******** BBR
        it('BBR0 should branch if bit 0 clear', function() {
            initMemory([[0x00, 0x33, [0xFE]]]);
            testCode([0x0F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBR0 should branch backward', function () {
            initMemory([[0x00, 0x33, [0xFE]]]);
            testCode([0x0F, 0x33, 0xFF], 1, {}, {
                cycles: 6,
                pc: 0x0402
            });
        });

        it('BBR1 should branch if bit 1 clear', function() {
            initMemory([[0x00, 0x33, [0xFD]]]);
            testCode([0x1F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBR2 should branch if bit 2 clear', function() {
            initMemory([[0x00, 0x33, [0xFB]]]);
            testCode([0x2F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBR3 should branch if bit 3 clear', function() {
            initMemory([[0x00, 0x33, [0xF7]]]);
            testCode([0x3F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBR4 should branch if bit 4 clear', function() {
            initMemory([[0x00, 0x33, [0xEF]]]);
            testCode([0x4F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBR5 should branch if bit 5 clear', function() {
            initMemory([[0x00, 0x33, [0xDF]]]);
            testCode([0x5F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBR6 should branch if bit 6 clear', function() {
            initMemory([[0x00, 0x33, [0xBF]]]);
            testCode([0x6F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBR7 should branch if bit 7 clear', function() {
            initMemory([[0x00, 0x33, [0x7F]]]);
            testCode([0x7F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBR0 should not branch if bit 0 set', function() {
            initMemory([[0x00, 0x33, [0x01]]]);
            testCode([0x0F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBR1 should not branch if bit 1 set', function() {
            initMemory([[0x00, 0x33, [0x02]]]);
            testCode([0x1F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBR2 should not branch if bit 2 set', function() {
            initMemory([[0x00, 0x33, [0x04]]]);
            testCode([0x2F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBR3 should not branch if bit 3 set', function() {
            initMemory([[0x00, 0x33, [0x08]]]);
            testCode([0x3F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBR4 should not branch if bit 4 set', function() {
            initMemory([[0x00, 0x33, [0x10]]]);
            testCode([0x4F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBR5 should not branch if bit 5 set', function() {
            initMemory([[0x00, 0x33, [0x20]]]);
            testCode([0x5F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBR6 should not branch if bit 6 set', function() {
            initMemory([[0x00, 0x33, [0x40]]]);
            testCode([0x6F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBR7 should not branch if bit 7 set', function() {
            initMemory([[0x00, 0x33, [0x80]]]);
            testCode([0x7F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        // ******** BBS
        it('BBS0 should branch if bit 0 set', function() {
            initMemory([[0x00, 0x33, [0x01]]]);
            testCode([0x8F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBS0 should branch backward', function () {
            initMemory([[0x00, 0x33, [0x01]]]);
            testCode([0x8F, 0x33, 0xFF], 1, {}, {
                cycles: 6,
                pc: 0x0402
            });
        });

        it('BBS1 should branch if bit 1 set', function() {
            initMemory([[0x00, 0x33, [0x02]]]);
            testCode([0x9F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBS2 should branch if bit 2 set', function() {
            initMemory([[0x00, 0x33, [0x04]]]);
            testCode([0xAF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBS3 should branch if bit 3 set', function() {
            initMemory([[0x00, 0x33, [0x08]]]);
            testCode([0xBF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBS4 should branch if bit 4 set', function() {
            initMemory([[0x00, 0x33, [0x10]]]);
            testCode([0xCF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBS5 should branch if bit 5 set', function() {
            initMemory([[0x00, 0x33, [0x20]]]);
            testCode([0xDF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBS6 should branch if bit 6 set', function() {
            initMemory([[0x00, 0x33, [0x40]]]);
            testCode([0xEF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBS7 should branch if bit 7 set', function() {
            initMemory([[0x00, 0x33, [0x80]]]);
            testCode([0xFF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0482
            });
        });

        it('BBS0 should not branch if bit 0 clear', function() {
            initMemory([[0x00, 0x33, [0xFE]]]);
            testCode([0x8F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBS1 should not branch if bit 1 clear', function() {
            initMemory([[0x00, 0x33, [0xFD]]]);
            testCode([0x9F, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBS2 should not branch if bit 2 clear', function() {
            initMemory([[0x00, 0x33, [0xFB]]]);
            testCode([0xAF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBS3 should not branch if bit 3 clear', function() {
            initMemory([[0x00, 0x33, [0xF7]]]);
            testCode([0xBF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBS4 should not branch if bit 4 clear', function() {
            initMemory([[0x00, 0x33, [0xEF]]]);
            testCode([0xCF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBS5 should not branch if bit 5 clear', function() {
            initMemory([[0x00, 0x33, [0xDF]]]);
            testCode([0xDF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBS6 should not branch if bit 6 clear', function() {
            initMemory([[0x00, 0x33, [0xBF]]]);
            testCode([0xEF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });

        it('BBS7 should not branch if bit 7 clear', function() {
            initMemory([[0x00, 0x33, [0x7B]]]);
            testCode([0xFF, 0x33, 0x7F], 1, {}, {
                cycles: 6,
                pc: 0x0403
            });
        });
    });

    describe('Bit set/reset', function () {
        it('RMB0 should reset bit 0', function() {
            initMemory([[0x00, 0x33, [0xFF]]]);
            testCode([0x07, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0xFE]]]);
        });

        it('RMB1 should reset bit 1', function() {
            initMemory([[0x00, 0x33, [0xFF]]]);
            testCode([0x17, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0xFD]]]);
        });

        it('RMB2 should reset bit 2', function() {
            initMemory([[0x00, 0x33, [0xFF]]]);
            testCode([0x27, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0xFB]]]);
        });

        it('RMB3 should reset bit 3', function() {
            initMemory([[0x00, 0x33, [0xFF]]]);
            testCode([0x37, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0xF7]]]);
        });

        it('RMB4 should reset bit 4', function() {
            initMemory([[0x00, 0x33, [0xFF]]]);
            testCode([0x47, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0xEF]]]);
        });

        it('RMB5 should reset bit 5', function() {
            initMemory([[0x00, 0x33, [0xFF]]]);
            testCode([0x57, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0xDF]]]);
        });

        it('RMB6 should reset bit 6', function() {
            initMemory([[0x00, 0x33, [0xFF]]]);
            testCode([0x67, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0xBF]]]);
        });

        it('RMB7 should reset bit 7', function() {
            initMemory([[0x00, 0x33, [0xFF]]]);
            testCode([0x77, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0x7F]]]);
        });

        it('SMB0 should set bit 0', function() {
            initMemory([[0x00, 0x33, [0x00]]]);
            testCode([0x87, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0x01]]]);
        });

        it('SMB1 should set bit 1', function() {
            initMemory([[0x00, 0x33, [0x00]]]);
            testCode([0x97, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0x02]]]);
        });

        it('SMB2 should set bit 2', function() {
            initMemory([[0x00, 0x33, [0x00]]]);
            testCode([0xA7, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0x04]]]);
        });

        it('SMB3 should set bit 3', function() {
            initMemory([[0x00, 0x33, [0x00]]]);
            testCode([0xB7, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0x08]]]);
        });

        it('SMB4 should set bit 4', function() {
            initMemory([[0x00, 0x33, [0x00]]]);
            testCode([0xC7, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0x10]]]);
        });

        it('SMB5 should set bit 5', function() {
            initMemory([[0x00, 0x33, [0x00]]]);
            testCode([0xD7, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0x20]]]);
        });

        it('SMB6 should set bit 6', function() {
            initMemory([[0x00, 0x33, [0x00]]]);
            testCode([0xE7, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0x40]]]);
        });

        it('SMB7 should set bit 7', function() {
            initMemory([[0x00, 0x33, [0x00]]]);
            testCode([0xF7, 0x33], 1, {}, {
                cycles: 5,
                pc: 0x0402
            });
            expectMemory([[0x00, 0x33, [0x80]]]);
        });
    });

    describe('#math', function() {
        // INC A
        it('should INC A', function() {
            testCode([0x1A], 1, {
                a: 0x44
            },{
                cycles: 2,
                a: 0x45
            });
        });

        // DEC A
        it('should DEC A', function() {
            testCode([0x3A], 1, {
                a: 0x44
            },{
                cycles: 2,
                a: 0x43
            });
        });
    });
});