apple2js/js/applesoft/decompiler.js

function ApplesoftDump(mem)
{
    var _mem = mem;

    var LETTERS = 
    "                                " +
    " !\"#$%&'()*+,-./0123456789:;<=>?" +
    "@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_" +
    "`abcdefghijklmnopqrstuvwxyz{|}~ ";
    var TOKENS = {
    0x80: "END",
    0x81: "FOR",
    0x82: "NEXT",
    0x83: "DATA",
    0x84: "INPUT",
    0x85: "DEL",
    0x86: "DIM",
    0x87: "READ",
    0x88: "GR",
    0x89: "TEXT",
    0x8a: "PR#",
    0x8b: "IN#",
    0x8c: "CALL",
    0x8d: "PLOT",
    0x8e: "HLIN",
    0x8f: "VLIN",
    0x90: "HGR2",
    0x91: "HGR",
    0x92: "HCOLOR=",
    0x93: "HPLOT",
    0x94: "DRAW",
    0x95: "XDRAW",
    0x96: "HTAB",
    0x97: "HOME",
    0x98: "ROT=",
    0x99: "SCALE=",
    0x9a: "SHLOAD",
    0x9b: "TRACE",
    0x9c: "NOTRACE",
    0x9d: "NORMAL",
    0x9e: "INVERSE",
    0x9f: "FLASH",
    0xa0: "COLOR=",
    0xa1: "POP=",
    0xa2: "VTAB",
    0xa3: "HIMEM:",
    0xa4: "LOMEM:",
    0xa5: "ONERR",
    0xa6: "RESUME",
    0xa7: "RECALL",
    0xa8: "STORE",
    0xa9: "SPEED=",
    0xaa: "LET",
    0xab: "GOTO",
    0xac: "RUN",
    0xad: "IF",
    0xae: "RESTORE",
    0xaf: "&",
    0xb0: "GOSUB",
    0xb1: "RETURN",
    0xb2: "REM",
    0xb3: "STOP",
    0xb4: "ON",
    0xb5: "WAIT",
    0xb6: "LOAD",
    0xb7: "SAVE",
    0xb8: "DEF",
    0xb9: "POKE",
    0xba: "PRINT",
    0xbb: "CONT",
    0xbc: "LIST",
    0xbd: "CLEAR",
    0xbe: "GET",
    0xbf: "NEW",
    0xc0: "TAB(",
    0xc1: "TO",
    0xc2: "FN",
    0xc3: "SPC(",
    0xc4: "THEN",
    0xc5: "AT",
    0xc6: "NOT",
    0xc7: "STEP",
    0xc8: "+",
    0xc9: "-",
    0xca: "*",
    0xcb: "/",
    0xcc: "^",
    0xcd: "AND",
    0xce: "OR",
    0xcf: ">",
    0xd0: "=",
    0xd1: "<",
    0xd2: "SGN",
    0xd3: "INT",
    0xd4: "ABS",
    0xd5: "USR",
    0xd6: "FRE",
    0xd7: "SCRN(",
    0xd8: "PDL",
    0xd9: "POS",
    0xda: "SQR",
    0xdb: "RND",
    0xdc: "LOG",
    0xdd: "EXP",
    0xde: "COS",
    0xdf: "SIN",
    0xe0: "TAN",
    0xe1: "ATN",
    0xe2: "PEEK",
    0xe3: "LEN",
    0xe4: "STR$",
    0xe5: "VAL",
    0xe6: "ASC",
    0xe7: "CHR$",
    0xe8: "LEFT$",
    0xe9: "RIGHT$",
    0xea: "MID$"
    };

    function readByte(addr) {
        var page = addr >> 8,
            off = addr & 0xff;

        return _mem.read(page, off);
    }

    function readWord(addr) {
        var lsb, msb;

        lsb = readByte(addr, debug);
        msb = readByte(addr + 1, debug);
        
        return (msb << 8) | lsb;
    }

    return {
        toString: function () {
            var str = "";
            var start = readWord(0x67); // Start
            var end = readWord(0xaf); // End of program
            var addr = start;
            do {
                var line = "";
                var next = readWord(addr);
                addr += 2;
                var lineno = readWord(addr);
                addr += 2;
                
                line += lineno;
                line += " ";
                var val = false;
                do {
                    if (addr < start || addr > end)
                    return str;
        
                    var val = readByte(addr++);
                    if (val > 0x80) {
                        line += " ";
                        line += TOKENS[val];
                        line += " ";
                    }
                    else
                        line += LETTERS[val];
                } while (val);
                line += "\n";
                str += line;
                addr = next;
            } while (addr && addr >= start && addr < end);
            
            return str;
        }
    };
}