[Sprig App] 6502 cpu emulator

games/6502-cpu-emulator.js

@@ -0,0 +1,162 @@
+// default code bc text wasnt working without it
+
+const player = "p"
+
+setLegend(
+  [ player, bitmap`
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000
+0000000000000000` ]
+)
+
+setSolids([])
+
+let level = 0
+const levels = [
+  map`
+pp
+pp`
+]
+
+setMap(levels[level])
+
+setPushables({
+  [ player ]: []
+})
+
+afterInput(() => {
+
+})
+
+// the code
+
+let A = 0; // A register
+let X = 0; // X register
+let Y = 0; // Y register
+let SP = 0xFF; // Stack Pointer
+let PC = 0; // Program counter (i will change this to be hex)
+let P = 0x24; // Processor status flag
+let memory = [0x49, 0x01, 0x8D, 0x02, 0x00, 0xE8, 0xEA, 0x00]; // mod this with the opcodes of any 6502 program youd like
+let delay = 2000 // delay between exec cycles (this is only here so you can read the logs)
+// convert SP and P to hex
+SP = "0x" + SP.toString(16).toUpperCase().padStart(2, '0');
+P = "0x" + P.toString(16).toUpperCase().padStart(2, '0');
+
+// logs
+  clearText()
+  addText("Register A="+A, {
+    x: 0,
+    y: 0,
+    color: color`2`
+  })
+  addText("Register X="+X, {
+    x: 0,
+    y: 1,
+    color: color`2`
+  })
+  addText("Register Y="+Y, {
+    x: 0,
+    y: 2,
+    color: color`2`
+  })
+  addText("Prog. Counter=" + PC, {
+    x: 0,
+    y: 3,
+    color: color`2`
+  })
+  addText("Stack Pointer=" + SP, {
+    x: 0,
+    y: 4,
+    color: color`2`
+  })
+  addText("Status=" + P, {
+    x: 0,
+    y: 5,
+    color: color`2`
+  })
+  addText("Delay=" + delay+"ms" , {
+    x: 0,
+    y: 6,
+    color: color`2`
+  })
+// main function
+function step() {
+  SP = "0x" + SP.toString(16).toUpperCase().padStart(2, '0');
+  P = "0x" + P.toString(16).toUpperCase().padStart(2, '0');
+  let opcode = memory[PC];
+  PC++;
+  console.log(`PC=${PC} A=${A} X=${X} MEM2=${memory[2]}`)
+  clearText()
+  addText("Register A="+A, {
+    x: 0,
+    y: 0,
+    color: color`2`
+  })
+  addText("Register X="+X, {
+    x: 0,
+    y: 1,
+    color: color`2`
+  })
+  addText("Register Y="+Y, {
+    x: 0,
+    y: 2,
+    color: color`2`
+  })
+  addText("Prog. Counter=" + PC, {
+    x: 0,
+    y: 3,
+    color: color`2`
+  })
+  addText("Stack Pointer=" + SP, {
+    x: 0,
+    y: 4,
+    color: color`2`
+  })
+  addText("Status=" + P, {
+    x: 0,
+    y: 5,
+    color: color`2`
+  })
+  addText("Delay=" + delay+"ms" , {
+    x: 0,
+    y: 6,
+    color: color`2`
+  })
+  if (opcode === 0xA9) {
+    A = memory[PC];
+    PC++
+  } else if (opcode === 0x8D) {
+    let lo = memory[PC]
+    let hi = memory[PC + 1];
+    let addr = lo + (hi << 8);
+    memory[addr] = A;
+    PC += 2;
+  } else if (opcode === 0xE8) {
+    X = (X + 1) & 0xFF;
+  } else if (opcode === 0xEA) {
+
+  } else if (opcode === 0x00) {
+    console.log("BRK");
+    return false;
+  } else {
+    console.log("Unknown opcode", opcode);
+    return false;
+  }
+  return true;
+}
+let interval = setInterval(() => {
+  if (!step()) clearInterval(interval);
+}, delay);