Clean up the CPU/ChipSet interface, and get the PC8080 Video component ready to actually do something

_posts/2016-04-30-the-intel-8080-cpu.md

@@ -46,11 +46,11 @@ The idea is to make [PC8080](/modules/pc8080/) sufficiently configurable so that
 [Space Invaders](/devices/pc8080/machine/invaders/)), as well as simpler terminal-based systems, like the CP/M-based
 systems of old.
 
-In fact, as soon as Space Invaders is working, my next planned adaptation is a DEC VT100 terminal emulator (itself
-an 8080-based machine) which can then be "wired up" to other PCjs machine simulations.  This will not be yet-another
-VT100-compatible emulation -- which, like 8080 emulators, has been done to death -- but rather a simulation
-of the original VT100 hardware, building on [Adam Mayer's](https://github.com/phooky) work
-[reverse-engineering the VT100](https://github.com/phooky/VT100-Hax).
+In fact, as soon as [Space Invaders](/devices/pc8080/machine/invaders/) is working, my next planned adaptation
+is a DEC VT100 terminal emulator (itself an 8080-based machine) which can then be "wired up" to other PCjs machine
+simulations.  This will not be yet-another VT100-compatible emulation -- which, like 8080 emulators, has been done to
+death -- but rather a simulation of the original VT100 hardware, building on [Adam Mayer's](https://github.com/phooky)
+work [reverse-engineering the VT100](https://github.com/phooky/VT100-Hax).
 
 *[@jeffpar](http://twitter.com/jeffpar)*  
 *April 30, 2016*

devices/pc8080/machine/invaders/README.md

@@ -24,5 +24,64 @@ Assorted [Space Invaders Hardware Notes](#space-invaders-hardware-notes) are col
 Space Invaders Hardware Notes
 ---
 
+### Memory Map
+
+	0000-1FFF  r   ROM code
+	2000-23FF  rw  RAM
+	2400-3FFF  rw  bitmapped screen (224x256)
+
+### I/O Map
+
+	00         r
+	01         r   control inputs
+	                bit 7
+	                bit 6    right
+	                bit 5    left
+	                bit 4    fire
+	                bit 3
+	                bit 2    1 player start
+	                bit 1    2 player start
+	                bit 0    coin slot
+	02         r   control inputs
+	                bit 7    0=display coin info
+	                bit 6    right 2
+	                bit 5    left 2
+	                bit 4    fire 2
+	                bit 3    bonus (1500,1000) / preset mode
+	                bit 2    1=tilt
+	                bit 0-1  initial lives (3,4,5,6) / (3,4)
+	02          w  shift count (0-7)
+	03         r   shifted value (low then high)
+	03          w  sound
+	                bit 4    bonus base
+	                bit 3    invader hit
+	                bit 2    base hit
+	                bit 1    base fire
+	                bit 0    saucer
+	04          w  value to shift
+	05          w  sound
+	                bit 5    flip video
+	                bit 4    saucer hit
+	                bit 3    invader movement 4
+	                bit 2    invader movement 3
+	                bit 1    invader movement 2
+	                bit 0    invader movement 1
+	06          w  watchdog timer clear
+
+Note that, unlike most emulators, PC8080 (like PCjs) has a *[Bus](/modules/pc8080/lib/bus.js)* architecture,
+allowing components to "plug in" different kinds of memory or memory-mapped devices at different addresses,
+and to register specific functions for specific I/O ports.	
+
+For example, Space Invaders has 8Kb of ROM at addresses 0x0000 through 0x1FFF, which means that if any 8080 code
+attempts to write to those addresses, nothing should happen.  Unfortunately, most emulators treat the entire address
+space as one contiguous array of bytes.  Which means either that the ROM is susceptible to corruption *or* that every
+write operation must check the address to determine its validity, which hurts the performance of *all* writes.
+
+In PC8080 (and PCjs), all writes are equally fast, and all ROMs are fully protected.  An exception is made for the
+Debugger, which allows you to use the "e" command to modify ("patch") ROM code on the fly, but that is completely
+outside and independent of the 8080 code being emulated.
+
+### Other Online References
+
 See [Computer Archeology](http://www.computerarcheology.com/Arcade/SpaceInvaders/) for an excellent collection
 of materials on the original Space Invaders, including commented ROM disassemblies. 

devices/pc8080/machine/invaders/machine.xml

@@ -9,7 +9,8 @@
 	<rom id="romF" addr="0x1000" size="0x0800" file="/devices/pc8080/rom/invaders/INVADERS-F.json"/>
 	<rom id="romE" addr="0x1800" size="0x0800" file="/devices/pc8080/rom/invaders/INVADERS-E.json"/>
 	<ram id="ram"  addr="0x2000" size="0x2000"/>
-	<video id="video" screenWidth="224" screenHeight="256" frameBuffer="0x2400" interruptRate="120" rotation="90" width="40%" pos="left" padding="8px">
+	<chipset id="chipset" model="SI1978"/>
+	<video id="video" screenWidth="224" screenHeight="256" bufferAddr="0x2400" bufferCols="256" bufferRows="224" bufferBits="1" interruptRate="120" rotation="90" width="40%" pos="left" padding="8px">
 		<menu>
 			<title>224x256 Screen (Rotated)</title>
 		</menu>

modules/pc8080/lib/chipset.js

@@ -68,7 +68,7 @@ function ChipSet(parmsChipSet)
         Component.notice("Unrecognized ChipSet model: " + model);
     }
 
-    this.model = ChipSet.MODELS[model];
+    this.model = ChipSet.MODELS[model] || ChipSet.SI_1978.MODEL;
 
     this.bSwitches = this.parseDIPSwitches(parmsChipSet['swDIP']);
 
@@ -276,7 +276,7 @@ ChipSet.prototype.reset = function()
     this.bStatus0 = 0;
     this.bStatus1 = 0;
     this.bStatus2 = 0;
-    this.bShiftData = 0;
+    this.wShiftData = 0;
     this.bShiftCount = 0;
     this.bSound1 = this.bSound2 = 0;
 };
@@ -293,7 +293,7 @@ ChipSet.prototype.save = function()
 {
     var state = new State(this);
     if (this.model == ChipSet.SI_1978.MODEL) {
-        state.set(0, [this.bStatus0, this.bStatus1, this.bStatus2, this.bShiftData, this.bShiftCount, this.bSound1, this.bSound2]);
+        state.set(0, [this.bStatus0, this.bStatus1, this.bStatus2, this.wShiftData, this.bShiftCount, this.bSound1, this.bSound2]);
     }
     return state.data();
 };
@@ -315,7 +315,7 @@ ChipSet.prototype.restore = function(data)
         this.bStatus0 = a[0];
         this.bStatus1 = a[1];
         this.bStatus2 = a[2];
-        this.bShiftData = a[3];
+        this.wShiftData = a[3];
         this.bShiftCount = a[4];
         this.bSound1 = a[5];
         this.bSound2 = a[6];
@@ -323,6 +323,34 @@ ChipSet.prototype.restore = function(data)
     return true;
 };
 
+/**
+ * start()
+ *
+ * Notification from the CPU that it's starting.
+ *
+ * @this {ChipSet}
+ */
+ChipSet.prototype.start = function()
+{
+    /*
+     * Currently, all we (may) do with this notification is allow the speaker to make noise.
+     */
+};
+
+/**
+ * stop()
+ *
+ * Notification from the CPU that it's stopping.
+ *
+ * @this {ChipSet}
+ */
+ChipSet.prototype.stop = function()
+{
+    /*
+     * Currently, all we (may) do with this notification is prevent the speaker from making noise.
+     */
+};
+
 /**
  * inSIStatus0(port, addrFrom)
  *
@@ -378,7 +406,7 @@ ChipSet.prototype.inSIStatus2 = function(port, addrFrom)
  */
 ChipSet.prototype.inSIShiftResult = function(port, addrFrom)
 {
-    var b = ((this.bShiftData << this.bShiftCount) >> 8) & 0xff;
+    var b = (this.wShiftData >> (8 - this.bShiftCount)) & 0xff;
     this.printMessageIO(port, null, addrFrom, "SHIFT.RESULT", b, true);
     return b;
 };
@@ -422,7 +450,7 @@ ChipSet.prototype.outSISound1 = function(port, b, addrFrom)
 ChipSet.prototype.outSIShiftData = function(port, b, addrFrom)
 {
     this.printMessageIO(port, b, addrFrom, "SHIFT.DATA", null, true);
-    this.bShiftData = b;
+    this.wShiftData = (b << 8) | (this.wShiftData >> 8);
 };
 
 /**
@@ -439,6 +467,19 @@ ChipSet.prototype.outSISound2 = function(port, b, addrFrom)
     this.bSound2 = b;
 };
 
+/**
+ * outSIWatchdog(port, b, addrFrom)
+ *
+ * @this {ChipSet}
+ * @param {number} port (0x06)
+ * @param {number} b
+ * @param {number} [addrFrom] (not defined if the Debugger is trying to write the specified port)
+ */
+ChipSet.prototype.outSIWatchdog = function(port, b, addrFrom)
+{
+    this.printMessageIO(port, b, addrFrom, "WATCHDOG", null, true);
+};
+
 /*
  * Port input notification tables
  */
@@ -456,7 +497,8 @@ ChipSet.aPortOutput = {
     0x02: ChipSet.prototype.outSIShiftCount,
     0x03: ChipSet.prototype.outSISound1,
     0x04: ChipSet.prototype.outSIShiftData,
-    0x05: ChipSet.prototype.outSISound2
+    0x05: ChipSet.prototype.outSISound2,
+    0x06: ChipSet.prototype.outSIWatchdog
 };
 
 /**

modules/pc8080/lib/cpu.js

@@ -1047,7 +1047,7 @@ CPU.prototype.startCPU = function(fUpdateFocus)
         if (this.cmp) this.cmp.start(this.aCounts.msStartRun, this.getCycles());
         this.flags.fRunning = true;
         this.flags.fStarting = true;
-        if (this.chipset) this.chipset.setSpeaker();
+        if (this.chipset) this.chipset.start();
         var controlRun = this.bindings["run"];
         if (controlRun) controlRun.textContent = "Halt";
         if (this.cmp) {
@@ -1091,7 +1091,7 @@ CPU.prototype.stopCPU = function(fComplete)
     this.nRunCycles = 0;
     if (this.flags.fRunning) {
         this.flags.fRunning = false;
-        if (this.chipset) this.chipset.setSpeaker();
+        if (this.chipset) this.chipset.stop();
         var controlRun = this.bindings["run"];
         if (controlRun) controlRun.textContent = "Run";
     }

modules/pc8080/lib/cpuops.js

@@ -2362,7 +2362,7 @@ CPUDef.opJNC = function()
 CPUDef.opOUT = function()
 {
     var port = this.getPCByte();
-    this.bus.checkPortOutputNotify(port, 1, this.regA);
+    this.bus.checkPortOutputNotify(port, 1, this.regA, this.offPC(-2));
     this.nStepCycles -= 10;
 };
 
@@ -2450,7 +2450,7 @@ CPUDef.opJC = function()
 CPUDef.opIN = function()
 {
     var port = this.getPCByte();
-    this.regA = this.bus.checkPortInputNotify(port, 1) & 0xff;
+    this.regA = this.bus.checkPortInputNotify(port, 1, this.offPC(-2)) & 0xff;
     this.nStepCycles -= 10;
 };
 

modules/pc8080/lib/cpusim.js

@@ -450,6 +450,18 @@ CPUSim.prototype.getPC = function()
     return this.regPC;
 };
 
+/**
+ * offPC()
+ *
+ * @this {CPUSim}
+ * @param {number} off
+ * @return {number}
+ */
+CPUSim.prototype.offPC = function(off)
+{
+    return (this.regPC + off) & 0xffff;
+};
+
 /**
  * setPC(off)
  *

modules/pc8080/lib/debugger.js

@@ -1578,6 +1578,9 @@ if (DEBUGGER) {
     /**
      * messageIO(component, port, bOut, addrFrom, name, bIn, bitsMessage)
      *
+     * Most (if not all) port handlers should provide a name for their respective ports, so if no name is provided,
+     * we assume this is an unknown port, and display a message by default.
+     *
      * @this {Debugger}
      * @param {Component} component
      * @param {number} port
@@ -1590,7 +1593,7 @@ if (DEBUGGER) {
     Debugger.prototype.messageIO = function(component, port, bOut, addrFrom, name, bIn, bitsMessage)
     {
         bitsMessage |= Messages.PORT;
-        if (addrFrom == null || (this.bitsMessage & bitsMessage) == bitsMessage) {
+        if (name == null || (this.bitsMessage & bitsMessage) == bitsMessage) {
             this.message(component.idComponent + '.' + (bOut != null? "outPort" : "inPort") + '(' + str.toHexWord(port) + ',' + (name? name : "unknown") + (bOut != null? ',' + str.toHexByte(bOut) : "") + ')' + (bIn != null? (": " + str.toHexByte(bIn)) : "") + (addrFrom != null? (" at " + this.toHexOffset(addrFrom)) : ""));
         }
     };
@@ -4499,7 +4502,11 @@ if (DEBUGGER) {
     {
         if (fSave) {
             if (!sCmd) {
+                if (this.fAssemble) {
+                    sCmd = "end";
+                } else {
                     sCmd = this.aPrevCmds[this.iPrevCmd+1];
+                }
             } else {
                 if (this.iPrevCmd < 0 && this.aPrevCmds.length) {
                     this.iPrevCmd = 0;

modules/pc8080/lib/video.js

@@ -50,11 +50,19 @@ if (NODE) {
  *      screenWidth: width of the screen canvas, in pixels
  *      screenHeight: height of the screen canvas, in pixels
  *      screenColor: background color of the screen canvas (default is black)
- *      aspectRatio
- *      frameBuffer
- *      interruptRate (eg, 120)
- *      refreshRate (eg, 60)
- *      rotation (eg, 90)
+ *      screenRotation: the amount of counter-clockwise rotation required (eg, 90)
+ *      aspectRatio (eg, 1.33)
+ *      bufferAddr: the starting address of the frame buffer (eg, 0x2400)
+ *      bufferCols: the width of a single frame buffer row, in pixels (eg, 256)
+ *      bufferRows: the number of frame buffer rows (eg, 224)
+ *      bufferBits: the number of bits per pixel (eg, 1)
+ *      interruptRate: normally the same as (or some multiple of) the refreshRate (eg, 120)
+ *      refreshRate: how many times updateScreen() should be called per second (eg, 60)
+ *
+ * We record all the above values now, but we defer creation of the frame buffer until our initBus()
+ * handler is called.  At that point, we will also compute the extent of the frame buffer, determine the
+ * appropriate "cell" size (ie, the number of pixels that updateScreen() will fetch and process at once),
+ * and allocate our cell cache.
  *
  * @constructor
  * @extends Component

modules/pcjs/lib/chipset.js

@@ -81,7 +81,7 @@ function ChipSet(parmsChipSet)
         Component.notice("Unrecognized ChipSet model: " + model);
     }
 
-    this.model = model && ChipSet.MODELS[model] || ChipSet.MODEL_5150_OTHER;
+    this.model = ChipSet.MODELS[model] || ChipSet.MODEL_5150_OTHER;
 
     var bSwitches;
     this.aDIPSwitches = [];
@@ -2126,6 +2126,36 @@ ChipSet.prototype.restore = function(data)
     return true;
 };
 
+/**
+ * start()
+ *
+ * Notification from the CPU that it's starting.
+ *
+ * @this {ChipSet}
+ */
+ChipSet.prototype.start = function()
+{
+    /*
+     * Currently, all we do with this notification is allow the speaker to make noise.
+     */
+    this.setSpeaker();
+};
+
+/**
+ * stop()
+ *
+ * Notification from the CPU that it's stopping.
+ *
+ * @this {ChipSet}
+ */
+ChipSet.prototype.stop = function()
+{
+    /*
+     * Currently, all we do with this notification is prevent the speaker from making noise.
+     */
+    this.setSpeaker();
+};
+
 ChipSet.aDMAControllerInit = [0, null, null, 0, new Array(4), 0];
 
 /**

modules/pcjs/lib/cpu.js

@@ -1052,7 +1052,7 @@ CPU.prototype.startCPU = function(fUpdateFocus)
         if (this.cmp) this.cmp.start(this.aCounts.msStartRun, this.getCycles());
         this.flags.fRunning = true;
         this.flags.fStarting = true;
-        if (this.chipset) this.chipset.setSpeaker();
+        if (this.chipset) this.chipset.start();
         var controlRun = this.bindings["run"];
         if (controlRun) controlRun.textContent = "Halt";
         if (this.cmp) {
@@ -1096,7 +1096,7 @@ CPU.prototype.stopCPU = function(fComplete)
     this.nRunCycles = 0;
     if (this.flags.fRunning) {
         this.flags.fRunning = false;
-        if (this.chipset) this.chipset.setSpeaker();
+        if (this.chipset) this.chipset.stop();
         var controlRun = this.bindings["run"];
         if (controlRun) controlRun.textContent = "Run";
     }

modules/pcjs/lib/video.js

@@ -52,18 +52,17 @@ if (NODE) {
  *
  *      model: model (eg, "mda" for Monochrome Display Adapter)
  *      mode: initial video mode (default is null, which selects a mode based on model)
- *      memory: amount of installed memory (ignored for MDA/CGA)
  *      screenWidth: width of the screen canvas, in pixels
  *      screenHeight: height of the screen canvas, in pixels
+ *      screenColor: background color of the screen canvas (default is black)
  *      scale: true for font scaling, false (default) to center the display on the screen
  *      charCols: number of character columns
  *      charRows: number of character rows
  *      fontROM: path to .rom file (or a JSON representation) containing the character set
- *      screenColor: background color of the screen canvas (default is black)
  *      touchScreen: string specifying desired touch-screen support (default is none)
  *      autoLock: true to (attempt to) auto-lock the mouse to the canvas (default is false)
  *
- * An EGA may specify the following additional properties:
+ * An EGA/VGA may specify the following additional properties:
  *
  *      switches: string representing EGA switches (see "SW1-SW4" documentation below)
  *      memory: the size of the EGA's on-board memory (overrides EGA's Video.cardSpecs)