Started work on a new assembler for the 6502 cpu. Something cleaner!

src/MOS/6502/assembler/op.js

+
+
+// Each array orders op codes as...
+// [<immediate>, <zero page>, <zero page X/Y>, <absolute>, <absolute X>, <absolute Y>, <Indirect X>, <Indirect Y>, <Indirect>, <accumulator>]
+// If an opcode does not support a particular format, null will be in that space.
+// NOTE: Opcode that do not have arguments will store their opcode value directly (no array).
+const CODES = {
+  "ADC":[0x69, 0x65, 0x75, 0x6D, 0x7D, 0x79, 0x61, 0x71, null, null],
+  "AND":[0x29, 0x25, 0x35, 0x2D, 0x3D, 0x39, 0x21, 0x31, null, null],
+  "ASL":[null, 0x06, 0x16, 0x0E, 0x1E, null, null, null, null, 0x0A],
+  "BCC":0x90,
+  "BCS":0xB0,
+  "BEQ":0xF0,
+  "BIT":[null, 0x24, null, 0x2C, null, null, null, null, null, null],
+  "BMI":0x30,
+  "BNE":0xD0,
+  "BPL":0x10,
+  "BRK":0x00,
+  "BVC":0x50,
+  "BVS":0x70,
+  "CLC":0x18,
+  "CLD":0xD8,
+  "CLI":0x58,
+  "CLV":0xB8,
+  "CMP":[0xC9, 0xC5, 0xD5, 0xCD, 0xDD, 0xD9, 0xC1, 0xD1, null, null],
+  "CPX":[0xE0, 0xE4, null, 0xEC, null, null, null, null, null, null],
+  "CPY":[0xC0, 0xC4, null, 0xCC, null, null, null, null, null, null],
+  "DEC":[null, 0xC6, 0xD6, 0xCE, 0xDE, null, null, null, null, null],
+  "DEX":0xCA,
+  "DEY":0x88,
+  "EOR":[0x49, 0x45, 0x55, 0x4D, 0x5D, 0x59, 0x41, 0x51, null, null],
+  "INC":[null, 0xE6, 0xF6, 0xEE, 0xFE, null, null, null, null, null],
+  "INX":0xE8,
+  "INY":0xC8,
+  "JMP":[null, null, null, 0x4C, null, null, null, null, 0x6C, null],
+  "JSR":[null, null, null, 0x20, null, null, null, null, null, null],
+  "LDA":[0xA9, 0xA5, 0xB5, 0xAD, 0xBD, 0xB9, 0xA1, 0xB1, null, null],
+  "LDX":[0xA2, 0xA6, 0xB6, 0xAE, 0xBE, null, null, null, null, null],
+  "LDY":[0xA0, 0xA4, 0xB4, 0xAC, 0xBC, null, null, null, null, null],
+  "LSR":[null, 0x46, 0x56, 0x4E, 0x5E, null, null, null, null, 0x4A],
+  "NOP":0xEA,
+  "ORA":[0x09, 0x05, 0x15, 0x0D, 0x1D, 0x19, 0x01, 0x11, null, null],
+  "PHA":0x48,
+  "PHP":0x08,
+  "PLA":0x68,
+  "PLP":0x28,
+  "ROL":[null, 0x26, 0x36, 0x2E, 0x3E, null, null, null, null, 0x2A],
+  "ROR":[null, 0x66, 0x76, 0x6E, 0x7E, null, null, null, null, 0x6A],
+  "RTI":0x40,
+  "RTS":0x60,
+  "SBC":[0xE9, 0xE5, 0xF5, 0xED, 0xFD, 0xF9, 0xE1, 0xF1, null, null],
+  "SEC":0x38,
+  "SED":0xF8,
+  "SEI":0x78,
+  "STA":[null, 0x85, 0x95, 0x8D, 0x9D, 0x99, 0x81, 0x91, null, null],
+  "STX":[null, 0x86, 0x96, 0x8E, null, null, null, null, null, null],
+  "STY":[null, 0x84, 0x94, 0x8C, null, null, null, null, null, null],
+  "TAX":0xAA,
+  "TAY":0xA8,
+  "TSX":0xBA,
+  "TXA":0x8A,
+  "TXS":0x9A,
+  "TYA":0x98
+};
+var NAMES = Object.keys(CODES);
+
+
+
+module.exports = Object.freeze({
+  MODES:{
+    IMMEDIATE: 0,
+    ZEROPAGE: 1,
+    ZEROPAGEXY: 2,
+    ABSOLUTE: 3,
+    ABSOLUTEX: 4,
+    ABSOLUTEY: 5,
+    INDIRECTX: 6,
+    INDIRECTY: 7,
+    INDIRECT: 8,
+    ACCUMULATOR: 9
+  },
+  CODES: CODES,
+  NAMES: NAMES,
+  isCode:function(op){return (NAMES.indexOf(op) >= 0);},
+  getCode:function(op, mode){
+    if (NAMES.indexOf(op) >= 0){
+      if (typeof(CODES[op]) === 'number')
+        return CODES[op];
+      return (!(mode >= 0 && mode <= 9)) ? CODES[op][mode] : null;
+    }
+    return null;
+  }
+});
+
+
+

src/MOS/6502/assembler/tokenizer.js

+
+
+function GetTextStream(input){
+  var pos = 0;
+  var line = 0;
+  var col = 0;
+
+  function peek(){
+    return input.getChar(pos);
+  }
+
+  function next(){
+    let c = input.charAt(pos);
+    pos += 1;
+    if (c === "\n"){
+      line += 1;
+      col = 0;
+    } else {col += 1;}
+    return c;
+  }
+
+  function eof(){
+    return (input.charAt(pos) === "");
+  }
+
+  function die(msg){
+    throw new Error(msg + " Line: " + line + ", Col: " + col);
+  }
+
+  return {
+    peek: peek,
+    get: next,
+    eof: eof
+  };
+}
+
+// ----------------------------------------------
+// VALIDATORS
+// ----------------------------------------------
+
+function isWhiteSpace(c){
+  return ("\t\n ".indexOf(c) >= 0);
+}
+
+function isStringStart(c){
+  return (c === "\"" || c === "'");
+}
+
+function isNumType(c){
+  return ("$%".indexOf(c) >= 0 || isDigit(c));
+}
+
+function isDigit(c){
+  return /[0-9]/i.test(c);
+}
+
+function isHex(c){
+  return /[0-9a-fA-F]/i.test(c);
+}
+
+function isBinary(c){
+  return ("01".indexOf(c) >= 0);
+}
+
+function isLabelStart(c){
+  return /[a-fA-F_]/i.test(c);
+}
+
+function isLabel(c){
+  return (isLabelStart(c) || isDigit(c));
+}
+
+function isPunctuation(c){
+  return (",()".indexOf(c) >= 0);
+}
+
+function isOp(c){
+  return ("=+-/*".indexOf(c) >= 0);
+}
+
+
+// ----------------------------------------------
+// Read Operations
+// ----------------------------------------------
+
+function skipComment(stream){
+  readWhile(stream, (c)=>{return c != "\n";});
+  stream.next();
+}
+
+function readHex(stream){
+  stream.next();
+  var str = readWhile(stream, isHex);
+  return {type:'number', val: parseInt(str, 16)};
+}
+
+function readBinary(stream){
+  stream.next();
+  var str = readWhile(stream, isBinary);
+  return {type:'number', val: parseInt(str, 2)};
+}
+
+function readNumber(stream){
+  let c = stream.peek();
+  if (c === "$")
+    return readHex(stream);
+  if (c === "%")
+    return readBinary(stream);
+
+  var dot = false;
+  var str = readWhile(stream, (c)=>{
+    if (c === "."){
+      if (dot){return false;}
+      dot = true;
+      return true;
+    }
+    return isDigit(c);
+  });
+  return {type:'number', val:parseFloat(str)};
+}
+
+
+function readString(stream, end){
+  var str = "";
+  var escaped = false;
+  stream.next();
+  while (!stream.eof()){
+    let c = stream.next();
+    if (escaped){
+      str += c;
+      escaped = false;
+    } else if (c === "\\"){
+      escaped = true;
+    } else if (c === end){
+      break;
+    } else {
+      str += c;
+    }
+  }
+  return {type: "string", val: str};
+}
+
+function readLabel(stream){
+  str = readWhile(stream, isLabel);
+  return {type:"label", val: str};
+}
+
+function readWhile(stream, validator){
+  var str = "";
+  while (!stream.eof() && validator(stream.peek()))
+    str += stream.next();
+  return str;
+}
+
+function nextToken(stream){
+  readWhile(stream, isWhiteSpace);
+  if (stream.eof()){return null;}
+  let c = stream.peek();
+  if (c === ";"){
+    skipComment(stream);
+    return nextToken(stream);
+  } else if (isStringStart(c)){
+    return readString(stream, c);
+  } else if (isNumType(c)){
+    return readNumber(stream);
+  } else if (isLabelStart(c)){
+    return readLabel(stream);
+  } else if (isPunctuation(c)){
+    return {type:"punctuation", val:stream.next()};
+  } else if (isMathOp(c)){
+    return {type:"op", val:stream.next()};
+  }
+  stream.die("Unable to process character '" + c + "'.");
+}
+
+
+function tokenize(input){
+  var stream = GetTextStream(input);
+  var tokens = [];
+  var t = nextToken(stream);
+  while (t !== null){
+    tokens.push(t);
+    t = nextToken(stream);
+  }
+  return tokens;
+}
+
+
+module.exports = tokenize;
+
+
+