Memory now has a peek() and poke() method; like read() and write() respectively, but will not trigger listeners.

src/memory/imem.js

@@ -13,11 +13,25 @@ class IMem{
   get byte(){return -1;}
   set byte(b){}
 
+  // Shorthand method for accessing an address and returning a byte.
+  // Same as...
+  //
+  // mem.address = <16 bit value>
+  // let res = mem.byte
+  //
+  // NOTE: This will trigger read listeners.
   read(a){
     this.address = a;
     return this.byte;
   }
 
+  // Shorthand method for accessing an address and setting it's byte.
+  // Same as...
+  //
+  // mem.address = <16 bit value>
+  // mem.byte = <1 byte value>
+  //
+  // NOTE: This will trigger write listeners.
   write(a, b){
     if (this.writable){
       this.address = a;
@@ -26,14 +40,26 @@ class IMem{
     return this;
   }
 
+  // Same as .read() but will NOT trigger read listeners.
+  peek(a){return 0;}
+  // Same as .write() but will NOT trigger write listeners.
+  poke(a, b){return this;}
+
+  // Starting at <address> will fill memory (regardless of whether
+  // it's ROM or RAM) with the values in <data>
+  // NOTE: <data> is assumed to only contain byte values.
   load(address, data){
     return this;
   }
 
+  // Clears 256 bytes of memory starting from <page> * 256
+  // NOTE: This affects both RAM and ROM.
   clearPage(page){
     return this;
   }
 
+  // Clears all memory
+  // NOTE: This affects both RAM and ROM.
   clear(){
     return this;
   }

src/memory/memory.js

@@ -56,6 +56,12 @@ class ROM extends IMem{
   }
 
 
+  peek(a){
+    a = Math.min(this.__map.length - 1, Math.max(0, a));
+    return this.__map[a];
+  }
+
+
   load(address, data){
     let dc = data;
     if (address < 0 || address >= this.__map.length)
@@ -115,6 +121,12 @@ class RAM extends ROM {
     this.__wlisteners.on(addr, fn);
     return this;
   }
+
+  poke(a, b){
+    a = Math.min(this.__map.length - 1, Math.max(0, a));
+    this.__map[a] = b & 0xFF;
+    return this;
+  }
 }
 
 
@@ -169,6 +181,17 @@ class Shadow extends IMem {
     return this;
   }
 
+  peek(a){
+    a = Math.min(this.__size - 1, Math.max(0, a)) % this.__map.length;
+    return this.__map[a];
+  }
+
+  poke(a, b){
+    if (a >= 0 && a < this.__map.length)
+      this.__map[a] = b & 0xFF;
+    return this;
+  }
+
   load(addr, data){
     let dc = data;
     if (addr < 0 || addr >= this.__size)

src/memory/mmc.js

@@ -85,6 +85,29 @@ class MMC extends IMem{
     }
   }
 
+  peek(a){
+    let v = 0;
+    if (this.__switches.length > 0){
+      let oa = this.address;
+      this.address = a; // Let this do ALL the work for me.
+      a = this.__switches[this.__sidx].mem.address;
+      v = this.__switches[this.__sidx].mem.peek(a);
+      this.address = oa;
+    }
+    return v;
+  }
+
+  poke(a, b){
+    if (this.__switches.length > 0){
+      let oa = this.address;
+      this.address = a;
+      a = this.__switches[this.__sidx].mem.address;
+      this.__switches[this.__sidx].mem.poke(a, b);
+      this.address = oa;
+    }
+    return this;
+  }
+
   load(addr, data){
     if (addr < 0 || addr > this.size)
       throw new RangeError("Memory address out of range.");

test/unit.src.memory.memory.spec.js

@@ -79,6 +79,17 @@ describe("Testing Memory Module", function(){
         expect(cb.callCount).to.equal(2);
       });
 
+      it("Peek", function(){
+        var cb = sinon.fake();
+        m2.onAddressRead(0x0101, cb);
+        expect(m2.peek(0x0101)).to.equal(0x77);
+        expect(cb.callCount).to.equal(0);
+        expect(m2.read(0x0101)).to.equal(0x77);
+        expect(cb.callCount).to.equal(1);
+        m2.peek(0x0101);
+        expect(cb.callCount).to.equal(1);
+      });
+
       it("Clear Page", function(){
         m2.clearPage(2);
         expect(m2.read(0x0200)).to.equal(0x00);
@@ -198,6 +209,30 @@ describe("Testing Memory Module", function(){
         expect(cb.callCount).to.equal(2);
       });
 
+      it("Peek", function(){
+        var cb = sinon.fake();
+        m2.onAddressRead(0x0101, cb);
+        expect(m2.peek(0x0101)).to.equal(0x77);
+        expect(cb.callCount).to.equal(0);
+        expect(m2.read(0x0101)).to.equal(0x77);
+        expect(cb.callCount).to.equal(1);
+        m2.peek(0x0101);
+        expect(cb.callCount).to.equal(1);
+      });
+
+      it("Poke", function(){
+        var cb = sinon.fake();
+        m2.onAddressWrite(0x0130, cb);
+        m2.poke(0x0130, 0x42);
+        expect(cb.callCount).to.equal(0);
+        expect(m2.peek(0x0130)).to.equal(0x42);
+        m2.write(0x0130, 0x46);
+        expect(cb.callCount).to.equal(1);
+        expect(m2.peek(0x0130)).to.equal(0x46);
+        m2.poke(0x0130, 0x42);
+        expect(cb.callCount).to.equal(1);
+      });
+
       it("Clear Page", function(){
         m2.clearPage(2);
         expect(m2.read(0x0200)).to.equal(0x00);
@@ -304,6 +339,9 @@ describe("Testing Memory Module", function(){
         expect(cb1.lastArg).to.equal(0x22);
       });
 
+      it("Peek");
+      it("Poke");
+
       it("Clear Page", function(){
         sm.clearPage(0);
         expect(sm.read(0x00)).to.equal(0x00);
@@ -324,7 +362,12 @@ describe("Testing Memory Module", function(){
 
   describe("Memory Management Controller (MMC) Class", function(){
     var mmc = new Mem.MMC();
-    mmc.connectMemory(new Mem.Memory.RAM(1));
+    var rcb = sinon.fake();
+    var wcb = sinon.fake();
+    let m1 = new Mem.Memory.RAM(1);
+    m1.onAddressRead(0x31, rcb);
+    m1.onAddressWrite(0x31, wcb);
+    mmc.connectMemory(m1);
     mmc.connectMemory(new Mem.Memory.RAM(2));
     mmc.connectMemory(new Mem.Memory.RAM(1));
 
@@ -425,6 +468,9 @@ describe("Testing Memory Module", function(){
       expect(mmc.address).to.equal(0x03FF);
     });
 
+    it("Peek");
+    it("Poke");
+
     it("Clear Page", function(){
       expect(mmc.read(0x0200)).to.equal(0x11);
       expect(mmc.read(0x0201)).to.equal(0x22);