debug.js

var debugSerial = 0;
var annotations = null;

function debug_init(romName) {
    debugSerial = (romBanks[1][0x3ffc] << 8) | romBanks[1][0x3ffd];

    if (!localStorage[debugSerial]) {
        annotations = {'romName': romName, 'labels': {}};
    } else {
        annotations = JSON.parse(localStorage[debugSerial]);
    }

    console.log('Debug initialised for ' + romName + ' serial 0x' + hexword(debugSerial), annotations);
}

function persistAnnotations() {
    localStorage[debugSerial] = JSON.stringify(annotations);
}

function setLabel(virtual, name) {
    if (!name || name.match(/^[0-9]/)) {
        delete annotations.labels[virtual];
    } else {
        annotations.labels[virtual] = name;
    }
    persistAnnotations();
    updateDebug();
}

function addressName(addr) {
    var virtual = virtualAddress(addr);
    if (annotations.labels[virtual]) {
        return '<span class="addr label" title="' + hexword(addr) + '">' + annotations.labels[virtual] + '</span>';
    }
    return null;
}


function addressHtml(addr) {
    var name = addressName(addr);
    if (name) {
        return name + ' (0x' + hexword(addr) + ')';
    } else {
        return '<span class="addr">0x' + hexword(addr) + '</span>';
    }
}

function labelHtml(addr) {
    var name = addressName(addr);
    if (name) {
        return name + ':';
    } else {
        return '<span class="addr">' + hexword(addr) + '</span>';
    }
}


function hexbyte(value) {
    return ((value >> 4) & 0xf).toString(16) +
        (value & 0xf).toString(16);
}

function endLabelEdit(content) {
    var addr = $(this).attr('title') || content.previous;
    var virtual = virtualAddress(parseInt(addr, 16));
    setLabel(virtual, content.current);
}

var disassPc = 0;

function updateDisassembly(address) {
    var disass = $('#disassembly');
    disassPc = address;
    disass.children().each(function () {
        var result = disassemble(address);
        var hex = "";
        for (var i = address; i < result[1]; ++i) {
            if (hex !== "") hex += " ";
            hex += hexbyte(readbyte(i));
        }
        $(this).find('.dis_addr').html(labelHtml(address));
        $(this).toggleClass('current', address === z80.pc);
        $(this).find('.instr_bytes').text(hex);
        $(this).find('.disassembly').html(result[0]);
        $(this).find('.addr')
            .editable({editBy: 'dblclick', editClass: 'editable', onSubmit: endLabelEdit})
            .keypress(function (e) {
                if (e.which === 13) $(this).blur();
            });
        address = result[1];
    });
}

function prevInstruction(address) {
    for (var startingPoint = address - 20; startingPoint !== address; startingPoint++) {
        var addr = startingPoint & 0xffff;
        while (addr < address) {
            var result = disassemble(addr);
            if (result[1] === address) {
                return addr;
            }
            addr = result[1];
        }
    }
    return 0;
}

function nextInstruction(address) {
    return disassemble(address)[1] & 0xffff;
}

function updateElement(elem, newVal) {
    elem.toggleClass('changed', newVal !== elem.text()).text(newVal);
}

function updateFlags(f) {
    var string = 'cnp_h_zs';
    for (var i = 0; i < 8; ++i) {
        var r = string[i];
        var elem = $('#z80_flag_' + r);
        if (f & 1) {
            r = r.toUpperCase();
        }
        if (elem) {
            updateElement(elem, r);
        }
        f >>= 1;
    }
}

function showDebug(pc) {
    $('#debug').show(200);
    for (var i = 0; i < $('#disassembly').children().length / 2; i++) {
        pc = prevInstruction(pc);
    }
    updateDebug(pc);
}

function updateDebug(pcOrNone) {
    if (pcOrNone === null) {
        pcOrNone = disassPc;
    }
    updateDisassembly(pcOrNone);
    for (var reg in z80) {
        var elem = $('#z80_' + reg);
        if (elem) {
            if (reg.length > 1 && reg[reg.length - 1] !== 'h' && reg[reg.length - 1] !== 'l') {
                updateElement(elem, hexword(z80[reg]));
            } else {
                updateElement(elem, hexbyte(z80[reg]));
            }
        }
    }
    var i = 0;
    $('#vdp_registers > div:visible .value').each(function () {
        updateElement($(this), hexbyte(vdp_regs[i++]));
    });
    i = 0;
    $('#pages .value').each(function () {
        updateElement($(this), hexbyte(pages[i++]));
    });
    updateFlags(z80.f);
}

function stepUntil(f) {
    audio_enable(true);
    breakpointHit = false;
    for (var i = 0; i < 65536; i++) {
        tstates = 0;
        event_next_event = 1;
        z80_do_opcodes(cycleCallback);
        if (f()) break;
    }
    showDebug(z80.pc);
    audio_enable(false);
}

function step() {
    var curpc = z80.pc;
    stepUntil(function () {
        return z80.pc !== curpc;
    });
}

function isUnconditionalJump(addr) {
    var result = disassemble(addr);
    return !!result[0].match(/^(JR 0x|JP|RET|RST)/);
}

function stepOver() {
    if (isUnconditionalJump(z80.pc)) {
        return step();
    }
    var nextPc = nextInstruction(z80.pc);
    stepUntil(function () {
        return z80.pc === nextPc;
    });
}

function isReturn(addr) {
    var result = disassemble(addr);
    return !!result[0].match(/^RET/);
}

function stepOut() {
    var sp = z80.sp;
    stepUntil(function () {
        if (z80.sp >= sp && isReturn(z80.pc)) {
            var nextInstr = nextInstruction(z80.pc);
            step();
            return z80.pc !== nextInstr;
        }
        return false;
    });
}

function debugKeyPress(key) {
    if ($('input:visible').length) {
        return true;
    }
    var keyStr = String.fromCharCode(key);
    switch (keyStr) {
        case 'k':
            updateDisassembly(prevInstruction(disassPc));
            break;
        case 'j':
            updateDisassembly(nextInstruction(disassPc));
            break;
        case 'n':
            step();
            break;
        case 'm':
            stepOver();
            break;
        case 'u':
            stepOut();
            break;
        case 'g':
            start();
            break;
    }
    return true;
}