feat: implement some AVR instructions + tests

1 files changed, 43 insertions, 0 deletions

diff --git a/src/cpu.ts b/src/cpu.ts
new file mode 100644
index 0000000..a6e0ab6
--- /dev/null
+++ b/src/cpu.ts
@@ -0,0 +1,43 @@
+import { u16, u8 } from './types';
+
+export interface ICPU {
+  readonly data: Uint8Array;
+  readonly dataView: DataView;
+  readonly progMem: Uint16Array;
+  readonly progBytes: Uint8Array;
+  pc: u16;
+  cycles: number;
+
+  readData(addr: u16): u8;
+  writeData(addr: u16, value: u8): void;
+}
+
+export type ICPUMemoryHook = (value: u8, oldValue: u8, addr: u16) => void;
+export interface ICPUMemoryHooks {
+  [key: number]: ICPUMemoryHook;
+}
+
+export class CPU implements ICPU {
+  readonly data = new Uint8Array(16384);
+  readonly data16 = new Uint16Array(this.data.buffer);
+  readonly dataView = new DataView(this.data.buffer);
+  readonly progBytes = new Uint8Array(this.progMem.buffer);
+  readonly writeHooks: ICPUMemoryHooks = [];
+
+  pc = 0;
+  cycles = 0;
+
+  constructor(public progMem: Uint16Array) {}
+
+  readData(addr: number) {
+    return this.data[addr];
+  }
+
+  writeData(addr: number, value: number) {
+    const hook = this.writeHooks[addr];
+    if (hook) {
+      hook(value, this.data[addr], addr);
+    }
+    this.data[addr] = value;
+  }
+}