another batch of instructions

1 files changed, 10 insertions, 0 deletions

diff --git a/instructions/DEC.ts b/instructions/DEC.ts
new file mode 100644
index 0000000..9f14487
--- /dev/null
+++ b/instructions/DEC.ts
@@ -0,0 +1,10 @@
+import type The65c02 from "../65c02.ts";
+
+export default function (this: The65c02, mode: string) {
+    const addr = this.getAddr(mode);
+    this.io.address.set(addr);
+    this.read();
+    const res = this.io.data.num() - 1;
+    this.io.data.set(res & 0xFF);
+    this.flagZN(res & 0xFF)
+}
\ No newline at end of file