Feature: Keypad simulation!

Refactor: Tidy up constants use for machine configuration

assembler.js

@@ -1,5 +1,11 @@
 const { logMemory, num2hex } = require('./logging.js');
-const { INITIAL_IP_ADDRESS, START_OF_DISPLAY_MEM, POINTER_TO_START_OF_DISPLAY_MEM } = require('./machine.config.js');
+const {
+  INITIAL_IP_ADDRESS,
+  DISPLAY_ADDR,
+  KEYPAD_ADDR,
+  POINTER_TO_DISPLAY,
+  POINTER_TO_KEYPAD
+} = require('./machine.config.js');
 
 // 1 = verbose
 // 2 = what i'm currently focusing on

cpu.js

@@ -1,7 +1,17 @@
+const readline = require('readline');
 const readlineSync = require('readline-sync');
 
-const { INITIAL_IP_ADDRESS, CYCLE_LIMIT } = require('./machine.config');
-const { num2hex, num2bin_4bit } = require('./logging.js');
+const {
+  INITIAL_IP_ADDRESS,
+  CYCLE_LIMIT,
+  KEYPAD_ADDR,
+  KEY_MAP,
+} = require('./machine.config');
+
+const {
+  num2hex,
+  num2bin_4bit,
+} = require('./logging.js');
 const display = require('./display.js');
 
 // STATE
@@ -272,6 +282,32 @@ function startCPU(code) {
   CPU.loadMemory(code);
   CPU.cycleCounter = 0;
   CPU.running = true;
+
+  // FIXME: This conflicts with single-stepping
+  // (you can single-step, but keys aren't passed
+  //  through to the Cardiograph)
+  //
+  // -> The fix is maybe to remove readlineSync,
+  // and instead stash the keypress into a buffer variable.*
+  // Then have the stepping function check that buffer,
+  // and then clear the buffer, each time it runs.
+  //
+  // * If it's in the set of keys that are relevant
+  //   to single-stepping.
+
+  // Start listening for keypresses...
+  readline.emitKeypressEvents(process.stdin);
+  if (process.stdin.setRawMode != null) {
+    process.stdin.setRawMode(true);
+  }
+  process.stdin.on('keypress', (str, key) => { // TODO: is it possible to turn this off again?
+    if (key.sequence === '\x03') process.exit();
+
+    str = str.toUpperCase();
+    if (str in KEY_MAP) {
+      CPU.memory[KEYPAD_ADDR] = KEY_MAP[str];
+    }
+  });
 }
 
 /**
@@ -304,7 +340,7 @@ async function stepCPU(debug = false) {
  * @param {Boolean}   [debug]      - Enable/disable debugging printouts
  * @param {Number}    [clockSpeed] - CPU clock speed in milliseconds
  **/
-exports.runProgram = (code, debug = false, clockSpeed = 10) => {
+exports.runProgram = (code, debug = false, clockSpeed = 100) => {
   startCPU(code);
   // Animate the output by pausing between steps
   const loop = setInterval(async () => {
@@ -348,7 +384,8 @@ function logCPUState(debug = false) {
     console.log('Mnemonic:', CPU.currentInstruction.mnemonic);
     console.log(`Machine:  $${num2hex(CPU.currentInstruction.opcode)} $${num2hex(CPU.currentInstruction.operand)}`);
     console.log();
-    console.log(`IP: $${num2hex(CPU.IP)}  Acc: $${num2hex(CPU.Acc)}  NZOC: ${num2bin_4bit(CPU.FLAGS)}  ${CPU.running ? "running" : "halted" }`);
+    console.log(`IP: $${num2hex(CPU.IP)}  Acc: $${num2hex(CPU.Acc)}  NZOC: ${num2bin_4bit(CPU.FLAGS)}`);
+    console.log(`KEY: $${num2hex(CPU.memory[KEYPAD_ADDR])}  ${CPU.running ? "running" : "halted" }`);
     console.log();
   console.groupEnd();
 };

display.js

@@ -1,4 +1,4 @@
-const { POINTER_TO_START_OF_DISPLAY_MEM } = require('./machine.config');
+const { POINTER_TO_DISPLAY } = require('./machine.config');
 const { num2hex } = require('./logging.js');
 
 /**
@@ -6,7 +6,7 @@ const { num2hex } = require('./logging.js');
  * @param {Uint8Array} mem - CPU memory
  **/
 const printDisplay = (mem) => {
-  const disp = mem[POINTER_TO_START_OF_DISPLAY_MEM];
+  const disp = mem[POINTER_TO_DISPLAY];
   for (let i = disp; i < disp + 16; i += 4) {
     console.log(`${num2hex(mem[i])} ${num2hex(mem[i+1])} ${num2hex(mem[i+2])} ${num2hex(mem[i+3])}`);
   }
@@ -17,7 +17,7 @@ const printDisplay = (mem) => {
  * @param {Uint8Array} mem - CPU memory
  **/
 const prettyPrintDisplay = (mem) => {
-  const disp = mem[POINTER_TO_START_OF_DISPLAY_MEM];
+  const disp = mem[POINTER_TO_DISPLAY];
   const num2pic = (n) => n > 0 ? '⚫' : '⚪';
   for (let i = disp; i < disp + 16; i += 4) {
     console.log(`${num2pic(mem[i])}${num2pic(mem[i+1])}${num2pic(mem[i+2])}${num2pic(mem[i+3])}`);

machine.config.js

@@ -1,11 +1,26 @@
 module.exports = {
-  "START_OF_DISPLAY_MEM": 0,
-  "POINTER_TO_START_OF_DISPLAY_MEM": 32,
-  "POINTER_TO_START_OF_KEYPAD_MEM": 33,
   "INITIAL_IP_ADDRESS":  48,
 
+  // Use these in CPU:
+  "DISPLAY_ADDR": 0,
+  "KEYPAD_ADDR": 32,
+  // Store the `X_ADDR`s at these addresses when assembling:
+  "POINTER_TO_DISPLAY": 33,
+  "POINTER_TO_KEYPAD": 34,
+
+  "KEY_MAP": {
+    // Same layout as COSMAC VIP / CHIP-8
+    // (This object maps qwerty keys to hex keys
+    // so that they are arranged in the same layout
+    // as the real keypad)
+    '1':'1',  '2':'2',  '3':'3',  '4':'C',
+    'Q':'4',  'W':'5',  'E':'6',  'R':'D',
+    'A':'7',  'S':'8',  'D':'9',  'F':'E',
+    'Z':'A',  'X':'0',  'C':'B',  'V':'F',
+  },
+
   // max number of times to step the CPU,
   // to stop endless loops
   // 0 = infinite
-  "CYCLE_LIMIT": 128,
+  "CYCLE_LIMIT": 256,
 }

readme.md

@@ -69,13 +69,36 @@ With single stepping + verbose debugging output:
 ## Memory map / Peripherals
 
 - `00-0F` - display (4x4)
-- `10-1F` - keypad? (details TBD)
-- `20   ` - pointer to display memory
-- `21   ` - pointer to keypad memory
-- `22-2F` - reserved for future use / variable storage
+- `10-19` - reserved for future use
+- `20   ` - keypad - value of the most recent keypress
+- `21   ` - pointer to display memory
+- `22   ` - pointer to keypad memory
+- `23-2F` - reserved for future use / variable storage
 - `30   ` - initial value for IP
 - `30-FF` - free
 
+### Keypad
+
+The value of the latest keypress on a hex keypad is stored at `$20`.
+(The keypad can also be relocated by changing the value  of the pointer-to-keypad at `$22`.)
+
+The keypad uses the same layout as the COSMAC VIP (and CHIP-8):
+
+```
+1 2 3 C
+4 5 6 D
+7 8 9 E
+A 0 B F
+```
+The CPU simulator maps the following Qwerty keys onto those values:
+
+```
+1 2 3 4
+Q W E R
+A S D F
+Z X C V
+```
+
 ## Assembly language
 
     ADD $01         ; comments follow a `;`

sketches/stdin-stream.js

@@ -0,0 +1,20 @@
+const readline = require('readline');
+
+readline.emitKeypressEvents(process.stdin);
+
+if (process.stdin.setRawMode != null) {
+  process.stdin.setRawMode(true);
+}
+
+process.stdin.on('keypress', (str, key) => {
+  console.log(str)
+  console.log(key)
+  if (key.sequence === '\x03') process.exit();
+})
+
+let i = 0;
+const loop = setInterval(async () => {
+  console.log('loop #', i);
+  if (i > 10) clearInterval(loop);
+  i += 1;
+}, 250);

test-programs/keypad.asm

@@ -0,0 +1,30 @@
+;; Test keypad input
+;; 2023-08-16
+
+; The latest keypress is shown in the top left corner of the display.
+; A loop counter is shown in the top right corner; the program ends when it reaches zero.
+; (For a 4x4 display.)
+
+#LOOPCOUNT $80
+
+#Z 2          ; the zero flag is #2
+#keypad   $20 ; magic memory location containing latest key pressed
+#loopIter $FF ; address of loop iterator
+#iterPx   $03 ; where to display iterator
+#keyPx    $00 ; where to display key
+
+LDA #LOOPCOUNT
+STO #loopIter
+
+@loop
+ LDA (#loopIter)
+ STO #iterPx     ; display loop iterator
+ LDA (#keypad)
+ STO #keyPx      ; display latest keypress
+ LDA (#loopIter)
+ SUB 1
+ STO #loopIter
+ FTG #Z
+ FHP #Z
+  END
+ JMP @loop