MOS6502 bug fixes, added compiler directive '.bytes'. All directives will now start with a period (including 'define'). Tests updated.

src/MOS6502.js

@@ -268,14 +268,41 @@ class Assembler{
       if (line === ""){return this;}
       if (line[0] !== ";"){ // Skip comment lines.
         line = line.split(";")[0].trim(); // Take out any trailing comments.
+        // Checking for any jump labels!
+        if (line.indexOf(":") >= 0){
+          let s = line.split(":");
+          let lbl = s[0].trim();
+          if (lbl.length <= 0)
+            throw new Error("Malformatted jump label at program address " + toHexString(this.__PC));
+          this.__StoreJmpLabel(lbl);
+          line = s[1].trim();
+          if (line.length <= 0){return this;} // Nothing left to process.
+        }
+        // Finally... tokenize the main command.
         var tokens = tokenize(line);
 
-        if (tokens[0].toLowerCase() === 'define'){
+        if (tokens[0].toLowerCase() === '.define'){
           // Variable label!!
           this.__StoreVarLabel(tokens[1], tokens[2]);  
-        } else if (tokens[0][tokens[0].length - 1] === ':'){
+        /*} else if (tokens[0][tokens[0].length - 1] === ':'){
           // Jump labels!
-          this.__StoreJmpLabel(tokens[0].substr(0, tokens[0].length - 1)); 
+          this.__StoreJmpLabel(tokens[0].substr(0, tokens[0].length - 1));*/
+        } else if (tokens[0].toLowerCase() === '.bytes'){
+          // Compiler directive. Treat all proceeding tokens as values and store them raw.
+          for(let i=1; i < tokens.length; i++){
+            let v = Number.NaN;
+            if (tokens[i].startsWith("$")){
+              v = parseInt(tokens[i].substr(1), 16);
+            } else if (tokens[i].startsWith("b")){
+              v = parseInt(tokens[i].substr(1), 2);
+            } else {
+              v = parseInt(tokens[i]);
+            }
+            if (isNaN(v) || v < 0 || v >= 256)
+              throw new Error("Byte list value is malformed or out of bounds at program address " + toHexString(this.__PC));
+            op.push(v);
+            this.__PC += 1;
+          };
         } else if (tokens[0].length === 3){
 
           let StoreSingleOp = (code)=>{
@@ -301,9 +328,9 @@ class Assembler{
               }
 
               if (!isNaN(v)){
-                if (v < this.__PC - 127 || v > this.__PC + 128)
-                  throw new Error("Branch exceeds maximum number of bytes on program address " + toHexString(this.__PC));
-                v = v - this.__PC;
+                if (v < (this.__PC+1) - 127 || v > (this.__PC+1) + 128)
+                  throw new Error("Branch exceeds maximum number of bytes on program address " + toHexString(this.__PC + 1));
+                v = v - (this.__PC + 1);
                 op.push(code);
                 op.push((v >= 0) ? v : v + 255);
                 this.__PC += 2;
@@ -666,6 +693,8 @@ class Assembler{
             case 'tya':
               procFailed = StoreSingleOp(0x98); break;
 // --- ---
+// EOL
+// --- ---
             default:
               throw new Error("Unknown op-code '" + tokens[0].toUpperCase() + "' at program address " + toHexString(this.__PC));
           }
@@ -691,6 +720,7 @@ class Assembler{
     this.__varlabels = {};
     this.__jmplabels = {};
     this.__result = [];
+    return this;
   }
 }
 

test/MOS6502.spec.js

@@ -22,8 +22,8 @@ describe("Testing MOS6502 Systems...", function(){
     });
 
     describe(".compile()", function(){
-      it("Variable definition", function(){
-        asm.compile("define TAG $44");
+      it(".define directive", function(){
+        asm.compile(".define TAG $44");
         let vars = asm.variables;
         expect(vars).to.have.key('TAG');
         expect(vars['TAG']).to.equal(0x44);
@@ -37,6 +37,40 @@ describe("Testing MOS6502 Systems...", function(){
         expect(jmp['loop']).to.equal(pc);
       });
 
+      it(".bytes directive", function(){
+        let res = asm.reset().compile(".BYTES $44, $55, $66, $77, b10110101, 128").result();
+        expect(res.length).to.equal(6);
+        expect(res[0]).to.equal(0x44);
+        expect(res[1]).to.equal(0x55);
+        expect(res[2]).to.equal(0x66);
+        expect(res[3]).to.equal(0x77);
+        expect(res[4]).to.equal(parseInt('10110101', 2));
+        expect(res[5]).to.equal(128);
+      });
+
+      it("Jump label before and after .byte directive", function(){
+        asm.reset();
+        let pc1 = asm.PC;
+        asm.compile("bytes: .bytes $44, $55, $66, $77");
+        let pc2 = asm.PC;
+        asm.compile("loop: BNE loop");
+
+        let jmp = asm.jumplabels;
+        //expect(jmp).to.have.key('bytes');
+        expect(jmp['bytes']).to.equal(pc1);
+        //expect(jmp).to.have.key('loop');
+        expect(jmp['loop']).to.equal(pc2);
+
+        let res = asm.result();
+        expect(res.length).to.equal(6);
+        expect(res[0]).to.equal(0x44);
+        expect(res[1]).to.equal(0x55);
+        expect(res[2]).to.equal(0x66);
+        expect(res[3]).to.equal(0x77);
+        expect(res[4]).to.equal(0xD0);
+        expect(res[5]).to.equal(0xFE);
+      });
+
       it("ADC Immediate", function(){
         asm.reset();
         asm.compile("ADC #$44");
@@ -433,6 +467,8 @@ describe("Testing MOS6502 Systems...", function(){
       it("STY Zero Page");
       it("STY Zero Page, X");
       it("STY Absolute");
+
+      // ------------------------------------------------------------- 
     });
   });