From 8b9bcb5026063487a5d362e086bdc3cf8f289e03 Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Thu, 2 Feb 2023 19:05:18 +1100
Subject: [PATCH] clear if bits

---
 src/processor/mod.rs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/processor/mod.rs b/src/processor/mod.rs
index 8c8885f..c670ea7 100644
--- a/src/processor/mod.rs
+++ b/src/processor/mod.rs
@@ -93,22 +93,32 @@ impl CPU {
             if get_bit(req_and_enabled, 0) {
                 // vblank
                 self.service_interrupt(0x40);
+                self.memory
+                    .set(0xFF0F, clear_bit(self.memory.get(0xFF0F), 0));
                 5
             } else if get_bit(req_and_enabled, 1) {
                 // lcd stat
                 self.service_interrupt(0x48);
+                self.memory
+                    .set(0xFF0F, clear_bit(self.memory.get(0xFF0F), 1));
                 5
             } else if get_bit(req_and_enabled, 2) {
                 // timer
                 self.service_interrupt(0x50);
+                self.memory
+                    .set(0xFF0F, clear_bit(self.memory.get(0xFF0F), 2));
                 5
             } else if get_bit(req_and_enabled, 3) {
                 // serial
                 self.service_interrupt(0x58);
+                self.memory
+                    .set(0xFF0F, clear_bit(self.memory.get(0xFF0F), 3));
                 5
             } else if get_bit(req_and_enabled, 4) {
                 // joypad
                 self.service_interrupt(0x60);
+                self.memory
+                    .set(0xFF0F, clear_bit(self.memory.get(0xFF0F), 4));
                 5
             } else {
                 0
@@ -235,6 +245,10 @@ fn get_bit(byte: u8, flag: u8) -> bool {
     return got > 0x0;
 }
 
+fn clear_bit(byte: u8, flag: u8) -> u8 {
+    byte & (!(1 << flag as u8))
+}
+
 fn rotate(byte: u8, direction: &Direction) -> (u8, bool) {
     match direction {
         Direction::Left => {