MOS6502.cpu increasing of program counter slightly modified, fixed some minor bugs. MOS6502.cpu tests updated to be cleaner and clearer and include from flag testing in the existing ADC/SBC tests.

src/MOS6502/cpu.js

@@ -19,8 +19,9 @@ function ProcessOp(cpu, mode){
   switch(cpu.__cycle){
     case 0:
       if (mode === 0){
-        cpu.__mem.address = cpu.__PC;
         PCUp(cpu, 1);
+        cpu.__mem.address = cpu.__PC;
+        //PCUp(cpu, 1);
         cpu.__opv = cpu.__mem.byte;
       }
       return (mode === 0 || mode === 9);
@@ -36,8 +37,9 @@ function ProcessOp(cpu, mode){
         case 4: // Absolute
         case 5: // Absolute, X
         case 6: // Absolute, Y
-          cpu.__mem.address = cpu.__PC;
           PCUp(cpu, 1);
+          cpu.__mem.address = cpu.__PC;
+          //PCUp(cpu, 1);
           cpu.__opv |= cpu.__mem.byte << 8;
           break;
         case 7: // Indirect, X
@@ -111,7 +113,7 @@ function ProcessOp(cpu, mode){
 }
 
 
-function ADC(cpu){ // To be used by both the ADC and SBC op codes.
+function ADC(cpu){
   let pmode = [0x69, 0x65, 0x75, null, 0x6D, 0x7D, 0x79, 0x61, 0x71, null].indexOf(cpu.__op);
   if (ProcessOp(cpu, pmode) === true){
     cpu.__op = -1;
@@ -922,7 +924,7 @@ class CPU{
             this.__cycle = 0;
             this.__mem.address = this.__PC;
             this.__op = this.__mem.byte;
-            PCUp(this, 1);
+            //PCUp(this, 1);
           }
         } else {
           switch(this.__op){
@@ -993,6 +995,8 @@ class CPU{
             case 0x84: case 0x94: case 0x8C:
               STY(this); break;
           }
+          if (this.__op < 0)
+            PCUp(this, 1);
         }
       }).bind(this);
     }

test/unit.src.MOS6502.cpu.spec.js

@@ -89,100 +89,114 @@ describe("Testing MOS6502 CPU...", function(){
   });
 
   describe("Testing ADC...", function(){
-    it("ADC Immediate", function(){
-      let prg = "CLC\n";
-      prg += "CLV\n";
-      prg += "CLD\n";
-      prg += "CLI\n";
-      prg += "LDA #$00\n";
-      prg += "ADC #$01\n";
-      prg += "ADC #$01\n";
-      asm.reset().compile(prg);
-      cpu.memory.clearPage(0);
-      cpu.memory.load(0, asm.result());
-      cpu.reset = true;
-      tick();
-      // Getting through the 4 clear flag calls. Each should take 2 ticks.
-      tick(); tick(); tick(); tick(); tick(); tick(); tick(); tick();
-      // Next two ticks for the LDA call
-      tick(); tick();
-      // Now processing the adds.
-      expect(cpu.A).to.equal(0);
-      tick();
-      expect(cpu.A).to.equal(0);
-      tick();
-      expect(cpu.A).to.equal(1);
-      tick();
-      expect(cpu.A).to.equal(1);
-      tick();
-      expect(cpu.A).to.equal(2);
-    });
+    describe("ADC Binary Mode...", function(){
+      it("ADC Immediate", function(){
+        let prg = "CLC\n";
+        prg += "CLV\n";
+        prg += "CLD\n";
+        prg += "CLI\n";
+        prg += "LDA #$00\n";
+        prg += "ADC #$01\n";
+        prg += "ADC #$01\n";
+        asm.reset().compile(prg);
+        cpu.memory.clearPage(0);
+        cpu.memory.load(0, asm.result());
+        cpu.reset = true;
+        tick(); // To reset;
+        while (cpu.PC !== 10){
+          switch(cpu.PC){
+            case 6:
+              expect(cpu.A).to.equal(0); break;
+            case 8:
+              expect(cpu.A).to.equal(1); break;
+            case 10:
+              expect(cpu.A).to.equal(2); break;
+          }
+          tick();
+        } 
+      });
 
-    it("ADC Zero Page");
-    it("ADC Zero Page, X");
-    it("ADC Absolute");
-    it("ADC Absolute, X");
-    it("ADC Absolute, Y");
-    it("ADC Indirect, X");
-    it("ADC Indirect, Y");
+      it("ADC Zero Page");
+      it("ADC Zero Page, X");
+      it("ADC Absolute");
+      it("ADC Absolute, X");
+      it("ADC Absolute, Y");
+      it("ADC Indirect, X");
+      it("ADC Indirect, Y"); 
+    });
 
-    it ("ADC Test Zero flag"/*, function(){
-      cpu.memory.clearPage(0);
-      cpu.memory.load(0, [0x18, 0xB8, 0xD8, 0x58, 0x69, 0xFF, 0x69, 0x01]);
-      // Getting through the 4 clear flag calls. Each should take 2 ticks.
-      tick(); tick(); tick(); tick(); tick(); tick(); tick(); tick();
-      // Now processing the adds.
-      expect(cpu.A).to.equal(0);
-      tick();
-      expect(cpu.A).to.equal(0);
-      tick();
-      expect(cpu.A).to.equal(1);
-      tick();
-      expect(cpu.A).to.equal(1);
-      tick();
-      expect(cpu.A).to.equal(2);
-    }*/);
+    describe("ADC Decimal (BCD) Mode...", function(){
+      it("ADC Immediate");
+      it("ADC Zero Page");
+      it("ADC Zero Page, X");
+      it("ADC Absolute");
+      it("ADC Absolute, X");
+      it("ADC Absolute, Y");
+      it("ADC Indirect, X");
+      it("ADC Indirect, Y"); 
+    });
   });
 
   describe("Testing SBC...", function(){
-    it("SBC Immediate", function(){
-      let prg = "SEC\n";
-      prg += "CLV\n";
-      prg += "CLD\n";
-      prg += "CLI\n";
-      prg += "LDA #$00\n";
-      prg += "SBC #$01\n";
-      prg += "SEC\n";
-      prg += "SBC #$01";
-      asm.reset().compile(prg);
-      cpu.memory.clearPage(0);
-      cpu.memory.load(0, asm.result());
-      cpu.reset = true;
-      tick();
-      // Getting through the 1 set and 3 clear flag calls. Each should take 2 ticks.
-      tick(); tick(); tick(); tick(); tick(); tick(); tick(); tick();
-      // Next two ticks for the LDA call
-      tick(); tick();
-      // Now processing the subtractions.
-      expect(cpu.A).to.equal(0);
-      tick();
-      expect(cpu.A).to.equal(0);
-      tick();
-      expect(cpu.A).to.equal(0xFF);
-      tick(); tick(); // Get through second SEC call.
-      tick();
-      expect(cpu.A).to.equal(0xFF);
-      tick();
-      expect(cpu.A).to.equal(0xFE);
+    describe("SBC Binary Mode...", function(){
+      it("SBC Immediate", function(){
+        let prg = "SEC\n";
+        prg += "CLV\n";
+        prg += "CLD\n";
+        prg += "CLI\n";
+        prg += "LDA #$01\n";
+        prg += "SBC #$01\n";
+        prg += "SBC #$01";
+        asm.reset().compile(prg);
+        cpu.memory.clearPage(0);
+        cpu.memory.load(0, asm.result());
+        cpu.reset = true;
+        tick(); // To reset;
+        while(cpu.PC !== 11){
+          // NOTE TO SELF: Depending on the OP code, these tests could be
+          // checked multiple times, as the cpu may sit at a program cntr
+          // for a couple cycles depending on the OP.
+          switch(cpu.PC){
+            case 1:
+              expect(cpu.C).to.be.equal(1); break;
+            case 6:
+              expect(cpu.A).to.be.equal(0x01); break;
+            case 8:
+              expect(cpu.A).to.be.equal(0x00);
+              expect(cpu.C).to.be.equal(1);
+              expect(cpu.Z).to.be.equal(1);
+              expect(cpu.N).to.be.equal(0);
+              break;
+            case 9:
+              expect(cpu.A).to.be.equal(0xFF);
+              expect(cpu.C).to.be.equal(0);
+              expect(cpu.Z).to.be.equal(0);
+              expect(cpu.N).to.be.equal(1);
+              break;
+          }
+          tick();
+        } 
+      });
+
+      it("SBC Zero Page");
+      it("SBC Zero Page, X");
+      it("SBC Absolute");
+      it("SBC Absolute, X");
+      it("SBC Absolute, Y");
+      it("SBC Indirect, X");
+      it("SBC Indirect, Y");
     });
 
-    it("SBC Zero Page");
-    it("SBC Zero Page, X");
-    it("SBC Absolute");
-    it("SBC Absolute, X");
-    it("SBC Absolute, Y");
-    it("SBC Indirect, X");
-    it("SBC Indirect, Y");
+    describe("SBC Decimal (BCD) Mode...", function(){
+      it("SBC Immediate");
+      it("SBC Zero Page");
+      it("SBC Zero Page, X");
+      it("SBC Absolute");
+      it("SBC Absolute, X");
+      it("SBC Absolute, Y");
+      it("SBC Indirect, X");
+      it("SBC Indirect, Y");
+    });
   });
 });