Started working a BCD helper, and an implementation of the MOS CIA chip.

src/MOSCIA.js

@@ -0,0 +1,129 @@
+const Clock = require('common/clock.js');
+
+function Num2BCD(n){
+  let v = (n < 9) ? Math.floor(n / 10) : 0;
+  v = (v << 4) | (n - (v * 10));
+  return v;
+}
+
+class MOSCIA{
+  constructor(){
+    this.__regsel = 0;
+
+    this.__CTA = 0;
+    this.__CTB = 0;
+
+    this.__timerA = 0;
+    this.__timerALatch = 0;
+    this.__timerB = 0;
+    this.__timerBLatch = 0;
+
+    this.__TODLatch = 0;
+    this.__TODTick = 0;
+    this.__10ths = 0;
+    this.__sec = 0;
+    this.__min = 0;
+    this.__hours = 0;
+  }
+
+  get RS(){return this.__regsel;}
+  set RS(rs){this.__regsel = rs & 0x0F;}
+
+  get DATA(){
+    let val = 0;
+    switch(this.__regsel){
+      case 0x00: // Peripheral Data A
+        break;
+      case 0x01: // Peripheral Data B
+        break;
+      case 0x02: // Data Direction Reg A
+        break;
+      case 0x03: // Data Direction Reg B
+        break;
+      case 0x04: // Timer A Low
+        break;
+      case 0x05: // Timer A High
+        break
+      case 0x06: // Timer B Low
+        break;
+      case 0x07: // Timer B High
+        break;
+      case 0x08: // 10th of Sec Reg
+        this.__TODLatch = 0;
+        return Num2BCD(this.__10ths); break;
+      case 0x09: // Seconds Reg
+        return Num2BCD(this.__sec); break;
+      case 0x0A: // Minutes Reg
+        return Num2BCD(this.__min); break;
+      case 0x0B: // Hours AM/PM Reg
+        this.__TODLatch = 1;
+        return Num2BCD(this.__hours); break;
+      case 0x0C: // Serial Data
+        break;
+      case 0x0D: // Interrupt Control
+        break;
+      case 0x0E: // Control Timer Reg A
+        break;
+      case 0x0F: // Control Timer Reg B
+        break;
+    }
+    return val;
+  }
+
+  set DATA(d){
+    switch(this.__regsel){
+      case 0x00: // Peripheral Data A
+        break;
+      case 0x01: // Peripheral Data B
+        break;
+      case 0x02: // Data Direction Reg A
+        break;
+      case 0x03: // Data Direction Reg B
+        break;
+      case 0x04: // Timer A Low
+        break;
+      case 0x05: // Timer A High
+        break
+      case 0x06: // Timer B Low
+        break;
+      case 0x07: // Timer B High
+        break;
+      case 0x08: // 10th of Sec Reg
+        break;
+      case 0x09: // Seconds Reg
+        break;
+      case 0x0A: // Minutes Reg
+        break;
+      case 0x0B: // Hours AM/PM Reg
+        break;
+      case 0x0C: // Serial Data
+        break;
+      case 0x0D: // Interrupt Control
+        break;
+      case 0x0E: // Control Timer Reg A
+        break;
+      case 0x0F: // Control Timer Reg B
+        break;
+    }
+  }
+
+  get CNT(){return 0;}
+  set CNT(c){}
+
+  get SP(){return 0;}
+  set SP(b){}
+
+  get TOD(){return 0;}
+  set TOD(b){
+    if (b <= 0 || this.__TODLatch > 0){return;}
+    this.__TODTick += 1;
+    if (this.__TODTick === 6){
+      this.__TODTick = this.__CTA & 0x01;
+    }
+  }
+}
+
+
+module.exports = MOSCIA;
+
+

src/utils/bcd.js

@@ -0,0 +1,39 @@
+
+
+function isValid(bcd, n){
+  for (let i=0; i < n; i++){
+    if ((bcd & 0xF) > 9)
+      return false;
+    bcd = bcd >> 4;
+  }
+  return true;
+}
+
+function dec2BCD(b, n){
+  ;
+}
+
+function BCD2Dec(bcd, n){
+  // TODO: Fix bug!
+  let v = 0
+  for (let i=0; i < n; i++){
+    bcd = bcd >> (i*4);
+    v += (bcd & 0x0F) * Math.pow(10,i);
+  }
+  return v;
+}
+
+function add(a, b, n){
+  let c = 0;
+  let v = 0;
+  for (i=0; i < (n*4); i += 4){
+    let nibA = (a >> i) & 0x0F;
+    let nibB = (b >> i) & 0x0F;
+    let r = nibA + nibB + c;
+    c = (r > 9) ? 1 : 0;
+    r = (c == 1) ? (r + 6) & 0x0F : r;
+    v = v | (r << i);
+  }
+  return v;
+}
+