diff --git a/src/main.rs b/src/main.rs
index 18f23c5..a056555 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -513,7 +513,7 @@ impl Machine {
             }
             OP::CMP => {
                 let a = self.read(ci.args[0]);
-                let b = self.read(ci.args[0]);
+                let b = self.read(ci.args[1]);
 
                 self.RSTAT.set(Flags::FZERO, a == 0 || b == 0);
                 self.RSTAT.set(Flags::FEQUL, a == b);