disassembler-x86-intel/lib/src/disam.js

An Intel x86 disassembler, generates assembly from Opcode

"use strict";
var __generator = (this && this.__generator) || function (thisArg, body) {
    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
    function verb(n) { return function (v) { return step([n, v]); }; }
    function step(op) {
        if (f) throw new TypeError("Generator is already executing.");
        while (_) try {
            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
            if (y = 0, t) op = [op[0] & 2, t.value];
            switch (op[0]) {
                case 0: case 1: t = op; break;
                case 4: _.label++; return { value: op[1], done: false };
                case 5: _.label++; y = op[1]; op = [0]; continue;
                case 7: op = _.ops.pop(); _.trys.pop(); continue;
                default:
                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
                    if (t[2]) _.ops.pop();
                    _.trys.pop(); continue;
            }
            op = body.call(thisArg, _);
        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
    }
};
Object.defineProperty(exports, "__esModule", { value: true });
exports._Disassembler = void 0;
var _32bit_adressing_table_modrm_1 = require("32bit-adressing-table-modrm");
var _Disassembler = /** @class */ (function () {
    function _Disassembler() {
        this._prefixMap = new Map().set('66', 'registerMode').set('67', 'addressMode');
        this.modRmSet = new Set(['80', '81', '83']);
        this._opCodeMap = new Map();
        this.generateOpCodeMap([this.createOpCode('add', ['80/0', 'b', '81/0', 'd', '83/0', 'b'])]);
    }
    _Disassembler.prototype.byteIterator = function (s) {
        var i;
        return __generator(this, function (_a) {
            switch (_a.label) {
                case 0:
                    i = 0;
                    _a.label = 1;
                case 1:
                    if (!(i < s.length)) return [3 /*break*/, 4];
                    return [4 /*yield*/, s[i] + s[i + 1]];
                case 2:
                    _a.sent();
                    _a.label = 3;
                case 3:
                    i += 2;
                    return [3 /*break*/, 1];
                case 4: return [2 /*return*/];
            }
        });
    };
    _Disassembler.prototype.disassemble = function (opCodes) {
        var iterator = this.byteIterator(opCodes);
        var currentByte = iterator.next().value;
        var prefix = this.fetchPrefix(currentByte);
        if (prefix) {
            currentByte = iterator.next().value;
        }
        var modRmByte;
        var possibleRegisters = [];
        if (this.modRmSet.has(currentByte)) {
            var nextByte = iterator.next().value;
            var searchResult = _32bit_adressing_table_modrm_1.Table.getReverseValueFromTable(nextByte);
            modRmByte = searchResult[1].pop();
            possibleRegisters = searchResult[0];
        }
        var op = this._opCodeMap.get(modRmByte ? currentByte + "/" + modRmByte : currentByte);
        var instruction = op === null || op === void 0 ? void 0 : op.instruction;
        var operand1 = possibleRegisters.length > 0 ? possibleRegisters[1] : undefined;
        var operand2 = this.getValueFromLength(iterator, prefix ? 'w' : op === null || op === void 0 ? void 0 : op.length);
        return instruction + ' ' + operand1 + ' ' + operand2;
    };
    _Disassembler.prototype.getValueFromLength = function (it, length) {
        if (length) {
            switch (length) {
                case 'b':
                    return it.next().value;
                case 'd':
                    return it.next().value + it.next().value + it.next().value + it.next().value;
                case 'w':
                    return it.next().value + it.next().value;
            }
        }
        return '';
    };
    _Disassembler.prototype.fetchPrefix = function (pref) {
        return this._prefixMap.get(pref);
    };
    _Disassembler.prototype.generateOpCodeMap = function (codes) {
        var _this = this;
        codes.forEach(function (c) {
            c.codes.forEach(function (c1) {
                _this._opCodeMap.set(c1.value, { instruction: c.instruction, length: c1.length });
            });
        });
    };
    _Disassembler.prototype.createOpCode = function (ins, codeAndLength) {
        var codes = [];
        for (var i = 0; i < codeAndLength.length; i += 2) {
            var code = codeAndLength[i];
            var length_1 = codeAndLength[i + 1];
            codes.push({ value: code, length: length_1 !== '' ? length_1 : undefined });
        }
        return { instruction: ins, codes: codes };
    };
    return _Disassembler;
}());
exports._Disassembler = _Disassembler;