diff --git a/src/processor/opcodes.rs b/src/processor/opcodes.rs
index 99bd2fb..ee66712 100644
--- a/src/processor/opcodes.rs
+++ b/src/processor/opcodes.rs
@@ -653,7 +653,7 @@ impl CPU {
                 addr.set_low(self.ld_immediate_byte());
                 self.reg.set_8(Reg8::A, self.memory.get(addr));
             }
-            0xF1 => self.reg.af = self.pop_word(),
+            0xF1 => self.reg.af = self.pop_word() & 0xF0,
             0xF2 => {
                 let mut addr: u16 = 0x0;
                 addr.set_high(0xFF);