Clean up CF handling (no more direct manipulation of result variables)

devices/pc8080/machine/exerciser/README.md

@@ -13,7 +13,7 @@ machines:
 8080 Exerciser Test Machine
 ---
 
-This is a test of [PC8080](/modules/pc8080/), a new 8080-based machine emulator being added to the
+This is a test of [PC8080](/modules/pc8080/), a new 8080-based machine emulator recently added to the
 PCjs Project.
 
 The test machine below loads a copy of the

modules/pc8080/lib/cpudef.js

@@ -71,7 +71,7 @@ var CPUDef = {
         SF:     0x0080,         // bit 7: Sign flag
         ALL:    0x00D5,         // all "arithmetic" flags (CF, PF, AF, ZF, SF)
         MASK:   0x00FF,         //
-        IF:     0x0200          // bit 9: Interrupt flag (for internal use only)
+        IF:     0x0200          // bit 9: Interrupt flag (set if interrupts enabled; for internal use only)
     },
     PARITY:  [                  // 256-byte array with a 1 wherever the number of set bits of the array index is EVEN
         1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
@@ -92,21 +92,21 @@ var CPUDef = {
         1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
     ],
     /*
-     * Bit values for intFlags
+     * Interrupt-related flags (stored in intFlags)
      */
     INTFLAG: {
         NONE:       0x00,
         INTL:       0x07,       // last interrupt level requested
         INTR:       0x08,       // set if interrupt has been requested
-        HALT:       0x10        // halt requested; see the HLT opcode
+        HALT:       0x10        // halt requested; see opHLT()
     },
     /*
      * Opcode definitions
      */
     OPCODE: {
-        HLT:    0x76,
+        HLT:    0x76,           // Halt
-        ACI:    0xCE,           // PS.ALL
+        ACI:    0xCE,           // Add with Carry Immediate (affects PS.ALL)
-        CALL:   0xCD,
+        CALL:   0xCD,           // Call
         RST0:   0xC7
         // to be continued....
     }

modules/pc8080/lib/cpuops.js

@@ -123,7 +123,7 @@ CPUDef.opRLC = function()
 {
     var carry = this.regA << 1;
     this.regA = (carry & 0xff) | (carry >> 8);
-    this.resultZeroCarry = (this.resultZeroCarry & 0xff) | (carry & 0x100);
+    this.updateCF(carry & 0x100);
     this.nStepCycles -= 4;
 };
 
@@ -136,7 +136,7 @@ CPUDef.opDADB = function()
 {
     var w;
     this.setHL(w = this.getHL() + this.getBC());
-    this.resultZeroCarry = (this.resultZeroCarry & 0xff) | ((w >> 8) & 0x100);
+    this.updateCF((w >> 8) & 0x100);
     this.nStepCycles -= 10;
 };
 
@@ -204,7 +204,7 @@ CPUDef.opRRC = function()
 {
     var carry = (this.regA << 8) & 0x100;
     this.regA = (carry | this.regA) >> 1;
-    this.resultZeroCarry = (this.resultZeroCarry & 0xff) | carry;
+    this.updateCF(carry);
     this.nStepCycles -= 4;
 };
 
@@ -282,8 +282,8 @@ CPUDef.opMVID = function()
 CPUDef.opRAL = function()
 {
     var carry = this.regA << 1;
-    this.regA = (carry & 0xff) | (this.resultZeroCarry >> 8);
+    this.regA = (carry & 0xff) | this.getCF();
-    this.resultZeroCarry = (this.resultZeroCarry & 0xff) | (carry & 0x100);
+    this.updateCF(carry & 0x100);
     this.nStepCycles -= 4;
 };
 
@@ -296,7 +296,7 @@ CPUDef.opDADD = function()
 {
     var w;
     this.setHL(w = this.getHL() + this.getDE());
-    this.resultZeroCarry = (this.resultZeroCarry & 0xff) | ((w >> 8) & 0x100);
+    this.updateCF((w >> 8) & 0x100);
     this.nStepCycles -= 10;
 };
 
@@ -362,9 +362,9 @@ CPUDef.opMVIE = function()
  */
 CPUDef.opRAR = function()
 {
-    var carry = (this.regA << 8) & 0x100;
+    var carry = (this.regA << 8);
-    this.regA = ((this.resultZeroCarry & 0x100) | this.regA) >> 1;
+    this.regA = ((this.getCF() << 8) | this.regA) >> 1;
-    this.resultZeroCarry = (this.resultZeroCarry & 0xff) | carry;
+    this.updateCF(carry & 0x100);
     this.nStepCycles -= 4;
 };
 
@@ -452,7 +452,7 @@ CPUDef.opDAA = function()
         CF = CPUDef.PS.CF;
     }
     this.regA = this.addByte(src);
-    this.updateCF(!!CF);
+    this.updateCF(CF? 0x100 : 0);
     this.nStepCycles -= 4;
 };
 
@@ -465,7 +465,7 @@ CPUDef.opDADH = function()
 {
     var w;
     this.setHL(w = this.getHL() + this.getHL());
-    this.resultZeroCarry = (this.resultZeroCarry & 0xff) | ((w >> 8) & 0x100);
+    this.updateCF((w >> 8) & 0x100);
     this.nStepCycles -= 10;
 };
 
@@ -623,7 +623,7 @@ CPUDef.opDADSP = function()
 {
     var w;
     this.setHL(w = this.getHL() + this.getSP());
-    this.resultZeroCarry = (this.resultZeroCarry & 0xff) | ((w >> 8) & 0x100);
+    this.updateCF((w >> 8) & 0x100);
     this.nStepCycles -= 10;
 };
 
@@ -689,7 +689,7 @@ CPUDef.opMVIA = function()
  */
 CPUDef.opCMC = function()
 {
-    this.updateCF(!this.getCF());
+    this.updateCF(this.getCF()? 0 : 0x100);
     this.nStepCycles -= 4;
 };
 

modules/pc8080/lib/cpusim.js

@@ -434,7 +434,7 @@ CPUSim.prototype.clearCF = function()
  * getCF()
  *
  * @this {CPUSim}
- * @return {number} 0 or CPUDef.PS.CF
+ * @return {number} 0 or 1 (CPUDef.PS.CF)
  */
 CPUSim.prototype.getCF = function()
 {
@@ -452,18 +452,14 @@ CPUSim.prototype.setCF = function()
 };
 
 /**
- * updateCF(fCarry)
+ * updateCF(CF)
  *
  * @this {CPUSim}
- * @param {boolean} fCarry
+ * @param {number} CF (0x000 or 0x100)
  */
-CPUSim.prototype.updateCF = function(fCarry)
+CPUSim.prototype.updateCF = function(CF)
 {
-    if (fCarry) {
+    this.resultZeroCarry = (this.resultZeroCarry & 0xff) | CF;
-        this.resultZeroCarry |= 0x100;
-    } else {
-        this.resultZeroCarry &= ~0x100;
-    }
 };
 
 /**
@@ -528,21 +524,6 @@ CPUSim.prototype.setAF = function()
     this.resultAuxOverflow = (~this.resultParitySign & 0x10) | (this.resultAuxOverflow & ~0x10);
 };
 
-/**
- * updateAF(fAuxCarry)
- *
- * @this {CPUSim}
- * @param {boolean} fAuxCarry
- */
-CPUSim.prototype.updateAF = function(fAuxCarry)
-{
-    if (fAuxCarry) {
-        this.setAF();
-    } else {
-        this.clearAF();
-    }
-};
-
 /**
  * clearZF()
  *