pcjs/modules/pdp10/lib/macro10.js

/**
 * @fileoverview My homage to MACRO-10: a work-alike assembler for the PDP-10
 * @author <a href="mailto:Jeff@pcjs.org">Jeff Parsons</a>
 * @copyright © Jeff Parsons 2012-2017
 *
 * This file is part of PCjs, a computer emulation software project at <http://pcjs.org/>.
 *
 * PCjs is free software: you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * PCjs is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with PCjs.  If not,
 * see <http://www.gnu.org/licenses/gpl.html>.
 *
 * You are required to include the above copyright notice in every modified copy of this work
 * and to display that copyright notice when the software starts running; see COPYRIGHT in
 * <http://pcjs.org/modules/shared/lib/defines.js>.
 *
 * Some PCjs files also attempt to load external resource files, such as character-image files,
 * ROM files, and disk image files. Those external resource files are not considered part of PCjs
 * for purposes of the GNU General Public License, and the author does not claim any copyright
 * as to their contents.
 */

"use strict";

if (NODE) {
    var Str = require("../../shared/lib/strlib");
    var Web = require("../../shared/lib/weblib");
    var Debugger = require("../../shared/lib/debugger");
    var PDP10 = require("./defines");
    var DebuggerPDP10 = require("./debugger");
}

/**
 * @class Macro10
 */
class Macro10 {
    /**
     * Macro10(sURL, nAddr, dbg, done)
     *
     * The done() callback is called after the resource has been loaded and parsed, with an error code
     * indicating overall success or failure.  The caller must use other methods to obtain further results.
     *
     * The callback is passed three parameters:
     *
     *      done(macro10, sURL, nErrorCode)
     *
     * If nErrorCode is zero, the assembly process completed successfully.
     *
     * For access to basic services (eg, println()), we rely on the caller.  This is NOT an extension of
     * Component, so those services are NOT part of this class.
     *
     * @this {Macro10}
     * @param {string} sURL (the URL of the resource to be assembled)
     * @param {number|null} nAddr (the absolute address to assemble the code at, if any)
     * @param {DebuggerPDP10} dbg (used to provide services like println() to the Macro10 class)
     * @param {function(Macro10,string,number)} done
     */
    constructor(sURL, nAddr, dbg, done)
    {
        this.sURL = sURL;
        this.nAddr = nAddr;
        this.done = done;

        /*
         * Set up all the services we need to use.
         */
        this.println = dbg && dbg.println || console.log;

        /*
         * Initialize all the tables that MACRO-10 uses.
         */
        this.tblMacros = {};
        this.tblSymbols = {};

        var macro10 = this;
        Web.getResource(sURL, null, true, function(sURL, sResource, nErrorCode) {
            if (!nErrorCode) {
                nErrorCode = macro10.parseFile(sURL, sResource);
            }
            macro10.done(macro10, sURL, nErrorCode);
        });
    }

    /**
     * parseFile(sPath, sContents)
     *
     * Begin the assembly process.
     *
     * @this {Macro10}
     * @param {string} sPath
     * @param {string} sContents
     * @return {number}
     */
    parseFile(sPath, sContents)
    {
        var sText = sContents;
        if (Str.endsWith(sPath, ".html")) {
            /*
             * We want to parse ONLY the text between <PRE>...</PRE> tags, and eliminate any HTML entities.
             */
            sText = "";
            var match, re = /<pre>([\s\S]*?)<\/pre>/gi;
            while (match = re.exec(sContents)) {
                var s = match[1];
                if (s.indexOf('&') >= 0) s = s.replace(/&lt;/gi, '<').replace(/&gt;/gi, '>').replace(/&amp;/gi, '&');
                sText += s;
            }
            match = sText.match(/&[a-z]+;/i);
            if (match) this.warning("unrecognized HTML entity: " + match[0]);
        }
        var i;
        var asLines = sText.split(/\r?\n/);
        for (i = 0; i < asLines.length; i++) {
            if (!this.parseLine(i + 1, asLines[i])) break;
        }
        return 0;
    }

    /**
     * parseLine(nLine, sLine)
     *
     * @this {Macro10}
     * @param {number} nLine (line number)
     * @param {string} sLine (line contents)
     * @return {boolean}
     */
    parseLine(nLine, sLine)
    {
        var reLine = /([A-Z$%.][0-9A-Z$%.]*[:=]|)\s*([^\s;]+|)\s*([^;]+|)\s*(;?.*)/i;
        var match = sLine.match(reLine);
        if (!match || match[4] && match[4].slice(0, 1) != ';') {
            this.warning("failed to parse line " + nLine + ": " + sLine);
            return false;
        }
        var sLabel = match[1];
        var sOperator = match[2];
        var sOperands = match[3].trim();
        var sComment = match[4].slice(1);
        if (sLabel) {
            var chSep = sLabel.slice(-1);
            sLabel = sLabel.slice(0, -1);
            if (chSep == ':') {
                this.addLabel(sLabel);
            } else {
                this.addVariable(sLabel, sOperands = sOperator + sOperands);
                sOperator = chSep;
            }
        }
        if (DEBUG) this.println(Str.toDec(nLine, 5) + ": label(" + sLabel + ") operator(" + sOperator + ") operands(" + sOperands + ") comment(" + sComment + ")");
        return true;
    }

    /**
     * warning(sWarning)
     *
     * @this {Macro10}
     * @param {string} sWarning
     */
    warning(sWarning)
    {
        this.println("warning: " + sWarning);
    }

    /**
     * addLabel(sLabel)
     *
     * @this {Macro10}
     * @param {string} sLabel
     */
    addLabel(sLabel)
    {
    }

    /**
     * addVariable(sVar, sExp)
     *
     * @this {Macro10}
     * @param {string} sVar
     * @param {string} sExp
     */
    addVariable(sVar, sExp)
    {
    }
}