feat: timers

2 files changed, 249 insertions, 219 deletions

diff --git a/src/cpu.effekt b/src/cpu.effekt
index acd6c79..4a18d22 100644
--- a/src/cpu.effekt
+++ b/src/cpu.effekt
@@ -42,6 +42,7 @@ def makeCPU() {r: Renderer} = {
   var last_key_update_time in global = getNow()
   var last_instruction_run_time in global = getNow()
   var last_display_update_time in global = getNow()
+  var last_timer_update in global = getNow()
 
   new CPU {
     def initCPU(rom: ByteArray) = {
@@ -49,253 +50,271 @@ def makeCPU() {r: Renderer} = {
       r.fill("black")
     }
     def cycleCPU() = {
-      val h = ram.getAddr(pc)
-      val l = ram.getAddr(pc + 1)
-      val inst = bitwiseOr(bitwiseShl(h.toInt(), 8), l.toInt())
-      // r.log("PC: " ++ show(pc))
-      // r.log("Instruction: " ++ show(inst))
+      val currentTime = getNow()
+      if (currentTime - last_instruction_run_time >= 2) { // ~500Hz
+        val h = ram.getAddr(pc)
+        val l = ram.getAddr(pc + 1)
+        val inst = bitwiseOr(bitwiseShl(h.toInt(), 8), l.toInt())
+        // r.log("PC: " ++ show(pc))
+        // r.log("Instruction: " ++ show(inst))
 
-      // Decode
-      val opcode = bitwiseShr(bitwiseAnd(inst, 61440), 12)
-      val nnn = bitwiseAnd(inst, 4095)
-      val nn = bitwiseAnd(inst, 255)
-      val n = bitwiseAnd(inst, 15)
-      val x = bitwiseAnd(bitwiseShr(inst, 8), 15)
-      val y = bitwiseAnd(bitwiseShr(inst, 4), 15)
+        // Decode
+        val opcode = bitwiseShr(bitwiseAnd(inst, 61440), 12)
+        val nnn = bitwiseAnd(inst, 4095)
+        val nn = bitwiseAnd(inst, 255)
+        val n = bitwiseAnd(inst, 15)
+        val x = bitwiseAnd(bitwiseShr(inst, 8), 15)
+        val y = bitwiseAnd(bitwiseShr(inst, 4), 15)
 
-      // Execute
-      opcode match {
-        case 0 => {
-          nn match {
-            // Clear the screen
-            case 224 => {
-              r.clear()
-              r.log("Clearing the screen...")
+        // Execute
+        opcode match {
+          case 0 => {
+            nn match {
+              // Clear the screen
+              case 224 => {
+                r.clear()
+                r.log("Clearing the screen...")
+                pc = pc + 2
+              }
+              // Return from a subroutine
+              case 238 => {
+                // pc = stack[Int].popFront[Int]().value[Int]()
+                pc = stack.popFront().getOrElse { 0 }
+              }
+            } else {
+              r.log("Unknown Instruction: " ++ show(inst))
+            }
+          }
+          // Jump to address NNN
+          case 1 => {
+            pc = nnn
+          }
+          // Call subroutine at NNN
+          case 2 => {
+            stack.pushFront(pc + 2)
+            pc = nnn
+          }
+          // Skip next instruction if VX == NN
+          case 3 => {
+            if (v.unsafeGet(x).toInt() == nn) {
               pc = pc + 2
             }
-            // Return from a subroutine
-            case 238 => {
-              // pc = stack[Int].popFront[Int]().value[Int]()
-              pc = stack.popFront().getOrElse { 0 }
+            pc = pc + 2
+            r.log("Skipping next instruction...")
+          }
+          // Skip next instruction if VX != NN
+          case 4 => {
+            if (v.unsafeGet(x).toInt() != nn) {
+              pc = pc + 2
             }
-          } else {
-            r.log("Unknown Instruction: " ++ show(inst))
+            pc = pc + 2
           }
-        }
-        // Jump to address NNN
-        case 1 => {
-          pc = nnn
-        }
-        // Call subroutine at NNN
-        case 2 => {
-          stack.pushFront(pc + 2)
-          pc = nnn
-        }
-        // Skip next instruction if VX == NN
-        case 3 => {
-          if (v.unsafeGet(x).toInt() == nn) {
+          // Skip next instruction if VX == VY
+          case 5 => {
+            if (v.unsafeGet(x).toInt() == v.unsafeGet(y).toInt()) {
+              pc = pc + 2
+            }
             pc = pc + 2
           }
-          pc = pc + 2
-        }
-        // Skip next instruction if VX != NN
-        case 4 => {
-          if (v.unsafeGet(x).toInt() != nn) {
+          // Set VX = NN
+          case 6 => {
+            v.set(x, nn)
             pc = pc + 2
           }
-          pc = pc + 2
-        }
-        // Skip next instruction if VX == VY
-        case 5 => {
-          if (v.unsafeGet(x).toInt() == v.unsafeGet(y).toInt()) {
+          // Set VX = VX + NN
+          case 7 => {
+            v.set(x, v.unsafeGet(x).toInt() + nn)
             pc = pc + 2
           }
-          pc = pc + 2
-        }
-        // Set VX = NN
-        case 6 => {
-          v.set(x, nn)
-          pc = pc + 2
-        }
-        // Set VX = VX + NN
-        case 7 => {
-          v.set(x, v.unsafeGet(x).toInt() + nn)
-          pc = pc + 2
-        }
-        case 8 => {
-          n match {
-            // Set VX = VY
-            case 0 => {
-              v.set(x, v.unsafeGet(y))
-            }
-            // Set VX = VX OR VY
-            case 1 => {
-              v.set(x, bitwiseOr(v.unsafeGet(x).toInt(), v.unsafeGet(y).toInt()))
-            }
-            // Set VX = VX AND VY
-            case 2 => {
-              v.set(x, bitwiseAnd(v.unsafeGet(x).toInt(), v.unsafeGet(y).toInt()))
-            }
-            // Set VX = VX XOR VY
-            case 3 => {
-              v.set(x, bitwiseXor(v.unsafeGet(x).toInt(), v.unsafeGet(y).toInt()))
-            }
-            // Set VX = VX + VY, set VF = carry
-            case 4 => {
-              val sum = v.unsafeGet(x).toInt() + v.unsafeGet(y).toInt()
-              v.set(15, if (sum > 255) 1 else 0)
-              v.set(x, sum)
-
-            }
-            // Set VX = VX - VY, set VF = NOT borrow
-            case 5 => {
-              v.set(15, if (v.unsafeGet(x).toInt() > v.unsafeGet(y).toInt()) 1 else 0)
-              v.set(x, v.unsafeGet(x).toInt() - v.unsafeGet(y).toInt())
-            }
-            // Set VX = VX SHR 1
-            case 6 => {
-              v.set(15, bitwiseAnd(v.unsafeGet(x).toInt(), 1))
-              v.set(x, bitwiseShr(v.unsafeGet(x).toInt(), 1))
-            }
-            // Set VX = VY - VX, set VF = NOT borrow
-            case 7 => {
-              v.set(15, if (v.unsafeGet(y).toInt() > v.unsafeGet(x).toInt()) 1 else 0)
-              v.set(x, v.unsafeGet(y).toInt() - v.unsafeGet(x).toInt())
+          case 8 => {
+            n match {
+              // Set VX = VY
+              case 0 => {
+                v.set(x, v.unsafeGet(y))
+              }
+              // Set VX = VX OR VY
+              case 1 => {
+                v.set(x, bitwiseOr(v.unsafeGet(x).toInt(), v.unsafeGet(y).toInt()))
+              }
+              // Set VX = VX AND VY
+              case 2 => {
+                v.set(x, bitwiseAnd(v.unsafeGet(x).toInt(), v.unsafeGet(y).toInt()))
+              }
+              // Set VX = VX XOR VY
+              case 3 => {
+                v.set(x, bitwiseXor(v.unsafeGet(x).toInt(), v.unsafeGet(y).toInt()))
+              }
+              // Set VX = VX + VY, set VF = carry
+              case 4 => {
+                r.log("Adding" ++ show(v.unsafeGet(x)) ++ " and " ++ show(v.unsafeGet(y)))
+                val sum = v.unsafeGet(x).toInt() + v.unsafeGet(y).toInt()
+                r.log("Sum: " ++ show(sum) ++ " Carry: " ++ show(if (sum > 255) 1 else 0))
+                v.set(15, if (sum > 255) 1 else 0)
+                v.set(x, sum.toByte())
+              }
+              // Set VX = VX - VY, set VF = NOT borrow
+              case 5 => {
+                v.set(15, if (v.unsafeGet(x).toInt() > v.unsafeGet(y).toInt()) 1 else 0)
+                v.set(x, v.unsafeGet(x).toInt() - v.unsafeGet(y).toInt())
+              }
+              // Set VX = VX SHR 1
+              case 6 => {
+                v.set(15, bitwiseAnd(v.unsafeGet(x).toInt(), 1))
+                v.set(x, bitwiseShr(v.unsafeGet(x).toInt(), 1))
+              }
+              // Set VX = VY - VX, set VF = NOT borrow
+              case 7 => {
+                v.set(15, if (v.unsafeGet(y).toInt() > v.unsafeGet(x).toInt()) 1 else 0)
+                v.set(x, v.unsafeGet(y).toInt() - v.unsafeGet(x).toInt())
+              }
+              // Set VX = VX SHL 1
+              case 14 => {
+                v.set(15, bitwiseAnd(v.unsafeGet(x).toInt(), 128))
+                v.set(x, bitwiseShl(v.unsafeGet(x).toInt(), 1))
+              }
+            } else {
+              r.log("Unknown Instruction: " ++ show(inst))
             }
-            // Set VX = VX SHL 1
-            case 14 => {
-              v.set(15, bitwiseAnd(v.unsafeGet(x).toInt(), 128))
-              v.set(x, bitwiseShl(v.unsafeGet(x).toInt(), 1))
+            pc = pc + 2
+          }
+          // Skip next instruction if VX != VY
+          case 9 => {
+            if (v.unsafeGet(x).toInt() != v.unsafeGet(y).toInt()) {
+              pc = pc + 2
             }
-          } else {
-            r.log("Unknown Instruction: " ++ show(inst))
+            pc = pc + 2
           }
-          pc = pc + 2
-        }
-        // Skip next instruction if VX != VY
-        case 9 => {
-          if (v.unsafeGet(x).toInt() != v.unsafeGet(y).toInt()) {
+          // Set I = NNN
+          case 10 => {
+            i = nnn
             pc = pc + 2
           }
-          pc = pc + 2
-        }
-        // Set I = NNN
-        case 10 => {
-          i = nnn
-          pc = pc + 2
-        }
-        // Jump to location NNN + V0
-        case 11 => {
-          pc = nnn + v.unsafeGet(0).toInt()
-        }
+          // Jump to location NNN + V0
+          case 11 => {
+            pc = nnn + v.unsafeGet(0).toInt()
+          }
 
-        // Set VX = random byte AND NN
-        case 12 => {
-          val randInt: Int = floor(random() * 255.0)
-          v.set(x, bitwiseAnd(randInt, nn))
-          pc = pc + 2
-        }
-        // Display n-byte sprite starting at memory location I at (VX, VY), set VF = collision
-        case 13 => {
-          val vx = v.unsafeGet(x).toInt()
-          val vy = v.unsafeGet(y).toInt()
-          var collision = false
-          var yline = 0
-          while (yline < n) {
-            val pixel = ram.getAddr(i + yline)
-            var xline = 0
-            while (xline < 8) {
-              if (bitwiseAnd(pixel.toInt(), bitwiseShr(128, xline)) != 0) {
-                if (r.get(vx + xline, vy + yline)) {
-                  collision = true
+          // Set VX = random byte AND NN
+          case 12 => {
+            val randInt: Int = floor(random() * 255.0)
+            v.set(x, bitwiseAnd(randInt, nn))
+            pc = pc + 2
+          }
+          // Display n-byte sprite starting at memory location I at (VX, VY), set VF = collision
+          case 13 => {
+            val vx = v.unsafeGet(x).toInt()
+            val vy = v.unsafeGet(y).toInt()
+            var collision = false
+            var yline = 0
+            while (yline < n) {
+              val pixel = ram.getAddr(i + yline)
+              var xline = 0
+              while (xline < 8) {
+                if (bitwiseAnd(pixel.toInt(), bitwiseShr(128, xline)) != 0) {
+                  if (r.get(vx + xline, vy + yline)) {
+                    collision = true
+                  }
+                  r.draw(vx + xline, vy + yline)
+                  // r.log("Drawing at: " ++ show(vx + xline) ++ ", " ++ show(vy + yline))
                 }
-                r.draw(vx + xline, vy + yline)
-                r.log("Drawing at: " ++ show(vx + xline) ++ ", " ++ show(vy + yline))
+                xline = xline + 1
               }
-              xline = xline + 1
+              yline = yline + 1
             }
-            yline = yline + 1
+            v.set(15, if (collision) 1 else 0)
+            pc = pc + 2
           }
-          v.set(15, if (collision) 1 else 0)
-          pc = pc + 2
-        }
-        case 14 => {
-          nn match {
-            // Skip next instruction if key with the value of VX is pressed
-            case 161 => {
-              // TODO: missing keyboard input
-              ()
-            }
-            // Skip next instruction if key with the value of VX is not pressed
-            case 158 => {
-              // TODO: missing keyboard input
-              ()
+          case 14 => {
+            nn match {
+              // Skip next instruction if key with the value of VX is pressed
+              case 161 => {
+                // TODO: missing keyboard input
+                ()
+              }
+              // Skip next instruction if key with the value of VX is not pressed
+              case 158 => {
+                // TODO: missing keyboard input
+                ()
+              }
+            } else {
+              r.log("Unknown Instruction: " ++ show(inst))
             }
-          } else {
-            r.log("Unknown Instruction: " ++ show(inst))
           }
-        }
-        case 15 => {
-          nn match {
-            // Set VX = delay timer value
-            case 7 => {
-              v.set(x, delay)
-            }
-            // Wait for a key press, store the value of the key in VX
-            case 10 => {
-              // TODO: missing keyboard input
-              ()
-            }
-            // SET delay timer = VX
-            case 21 => {
-              delay = v.unsafeGet(x)
-            }
-            // Set sound timer = VX
-            case 24 => {
-              sound = v.unsafeGet(x)
-            }
-            // SET I = I + VX
-            case 30 => {
-              i = i + v.unsafeGet(x).toInt()
-            }
-            // Set I = location of sprite for digit VX
-            case 41 => {
-              i = v.unsafeGet(x).toInt() * 5
-            }
-            // Store BCD representation of VX in memory locations I, I+1, and I+2
-            case 51 => {
-              val vx = v.unsafeGet(x).toInt()
-              ram.setAddr(i, (vx / 100).toByte())
-              ram.setAddr(i + 1, mod((vx / 10), 10).toByte())
-              ram.setAddr(i + 2, mod(vx, 10).toByte())
-            }
-            // Store registers V0 through VX in memory starting at location I
-            case 85 => {
-              var index = 0
-              while (index <= x) {
-                ram.setAddr(i + index, v.unsafeGet(index))
-                index = index + 1
+          case 15 => {
+            nn match {
+              // Set VX = delay timer value
+              case 7 => {
+                v.set(x, delay)
               }
-              i = i + x + 1
-            }
-            // Read registers V0 through VX from memory starting at location I
-            case 101 => {
-              var index = 0
-              while (index <= x) {
-                v.set(index, ram.getAddr(i + index))
-                index = index + 1
+              // Wait for a key press, store the value of the key in VX
+              case 10 => {
+                // TODO: missing keyboard input
+                ()
+              }
+              // SET delay timer = VX
+              case 21 => {
+                delay = v.unsafeGet(x)
+              }
+              // Set sound timer = VX
+              case 24 => {
+                sound = v.unsafeGet(x)
+              }
+              // SET I = I + VX
+              case 30 => {
+                i = i + v.unsafeGet(x).toInt()
+              }
+              // Set I = location of sprite for digit VX
+              case 41 => {
+                i = v.unsafeGet(x).toInt() * 5
+              }
+              // Store BCD representation of VX in memory locations I, I+1, and I+2
+              case 51 => {
+                val vx = v.unsafeGet(x).toInt()
+                ram.setAddr(i, (vx / 100).toByte())
+                ram.setAddr(i + 1, mod((vx / 10), 10).toByte())
+                ram.setAddr(i + 2, mod(vx, 10).toByte())
               }
-              i = i + x + 1
+              // Store registers V0 through VX in memory starting at location I
+              case 85 => {
+                var index = 0
+                while (index <= x) {
+                  ram.setAddr(i + index, v.unsafeGet(index))
+                  index = index + 1
+                }
+                i = i + x + 1
+              }
+              // Read registers V0 through VX from memory starting at location I
+              case 101 => {
+                var index = 0
+                while (index <= x) {
+                  v.set(index, ram.getAddr(i + index))
+                  index = index + 1
+                }
+                i = i + x + 1
+              }
+            } else {
+              r.log("Unknown Instruction: " ++ show(inst))
             }
-          } else {
-            r.log("Unknown Instruction: " ++ show(inst))
+            pc = pc + 2
+          }
+        } else {
+          r.log("Unknown Instruction: " ++ show(inst))
+        }
+        last_instruction_run_time = getNow()
+
+        // Update timers if needed
+        if (currentTime - last_timer_update >= 16) { // 60Hz timer updates
+          // Update timers
+          if (delay.toInt() > 0) {
+            delay = (delay.toInt() - 1).toByte()
+          }
+          if (sound.toInt() > 0) {
+            sound = (sound.toInt() - 1).toByte()
           }
-          pc = pc + 2
+          
+          last_timer_update = currentTime
         }
-      } else {
-        r.log("Unknown Instruction: " ++ show(inst))
       }
-      last_instruction_run_time = getNow()
     }
   }
 }
diff --git a/src/renderers/js.effekt b/src/renderers/js.effekt
index 080555d..ab7cc53 100644
--- a/src/renderers/js.effekt
+++ b/src/renderers/js.effekt
@@ -44,13 +44,24 @@ val pageContent = """
       <input type="file" id="rom" accept=".ch8" />
       <button id="start" disabled>Start</button>
       <hr />
-      <canvas id="canvas" width="640" height="320"></canvas>
+      <canvas id="canvas" width="640" height="320" style="border: 10px solid black;"></canvas>
       <hr />
       <div>
         <h3>Logs:</h3>
         <pre id="logs"></pre>
       </div>
     </body>
+    <style>
+      body {
+        font-family: Arial, sans-serif;
+        margin: 0;
+        padding: 0;
+      }
+      canvas {
+        display: block;
+        margin: 0 auto;
+      }
+    </style>
   </html>
 """
 
@@ -112,7 +123,7 @@ extern io def get(x: Int, y: Int): Bool = jsWeb """
 extern io def update(f: () => Unit at {io, global}): Unit = jsWeb """
   setInterval(() => {
     $effekt.runToplevel((ks) => ${f}(ks));
-  }, 1000 / 60);
+  }, 1000 / 120);
 """
 
 namespace JSRenderer {