1 files changed, 21 insertions, 0 deletions
diff --git a/instructions/ROR.ts b/instructions/ROR.ts
new file mode 100644
index 0000000..7226604
--- /dev/null
+++ b/instructions/ROR.ts
@@ -0,0 +1,21 @@
+import type The65c02 from "../65c02.ts";
+
+export default function (this: The65c02, mode: string) {
+    if (mode == 'implicit') {
+        const mem = this.regA.num();
+        const result = (mem >> 1) | (this.carry ? 128 : 0);
+        this.negative = (result & 256) != 0
+        this.carry = (mem & 256) != 0
+        this.regA.set(result & 0xFF);
+    } else {
+        const addr = this.getAddr(mode)
+        this.io.address.set(addr);
+        this.read()
+        const mem = this.io.data.num();
+        const result = (mem >> 1) | (this.carry ? 128 : 0);
+        this.negative = (result & 256) != 0
+        this.carry = (mem & 256) != 0
+        this.io.data.set(result & 0xFF);
+        this.write()
+    }
+}
\ No newline at end of file