From 198ced9cb6b841624abbb144a41901954c9d4839 Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Thu, 16 Mar 2023 11:04:44 +1100
Subject: [PATCH] serial waits for ime

---
 gb-vst/src/lib.rs                       |  2 --
 lib/src/processor/memory.rs             |  2 +-
 lib/src/processor/memory/mmio/serial.rs | 11 +++++++----
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/gb-vst/src/lib.rs b/gb-vst/src/lib.rs
index e25a38d..782c64c 100644
--- a/gb-vst/src/lib.rs
+++ b/gb-vst/src/lib.rs
@@ -124,7 +124,6 @@ impl Plugin for GameboyEmu {
                             velocity: _,
                         } => {
                             if channel < 5 {
-                                println!("noteon: {as_bytes:#?}");
                                 vars.serial_tx.send(0x90 + channel).unwrap();
                                 vars.serial_tx.send(as_bytes[1]).unwrap();
                                 vars.serial_tx.send(as_bytes[2]).unwrap();
@@ -138,7 +137,6 @@ impl Plugin for GameboyEmu {
                             velocity: _,
                         } => {
                             if channel < 5 {
-                                println!("noteoff: {as_bytes:#?}");
                                 vars.serial_tx.send(0x80 + channel).unwrap();
                                 vars.serial_tx.send(as_bytes[1]).unwrap();
                                 vars.serial_tx.send(as_bytes[2]).unwrap();
diff --git a/lib/src/processor/memory.rs b/lib/src/processor/memory.rs
index 2090ca1..b9e1a8b 100644
--- a/lib/src/processor/memory.rs
+++ b/lib/src/processor/memory.rs
@@ -314,7 +314,7 @@ impl<ColourFormat: From<Colour> + Clone> Cpu<ColourFormat> {
 
         self.memory.apu.tick(steps);
 
-        let serial_interrupt = self.memory.serial.tick(steps);
+        let serial_interrupt = self.memory.serial.tick(steps, self.memory.ime);
         self.memory
             .interrupts
             .set_interrupt(Interrupt::Serial, serial_interrupt);
diff --git a/lib/src/processor/memory/mmio/serial.rs b/lib/src/processor/memory/mmio/serial.rs
index 1e73062..a5407b9 100644
--- a/lib/src/processor/memory/mmio/serial.rs
+++ b/lib/src/processor/memory/mmio/serial.rs
@@ -57,7 +57,7 @@ struct InputByte {
     input_delay: usize,
 }
 
-const BYTE_DELAY: usize = 20000;
+const BYTE_DELAY: usize = 2000;
 
 impl InputByte {
     fn advance(&mut self, rx: &Option<Receiver<u8>>) -> u8 {
@@ -154,7 +154,7 @@ impl Serial {
         !matches!(&self.target, SerialTarget::None)
     }
 
-    pub fn tick(&mut self, steps: usize) -> bool {
+    pub fn tick(&mut self, steps: usize, ime: bool) -> bool {
         let mut will_interrupt = false;
         if !self.is_connected() {
             return false;
@@ -165,11 +165,14 @@ impl Serial {
             &None
         };
         for _ in 0..steps {
-            self.input_byte.input_delay = self.input_byte.input_delay.saturating_sub(1);
+            if ime {
+                self.input_byte.input_delay = self.input_byte.input_delay.saturating_sub(1);
+            }
             if (self.control.transfer_in_progress
                 && self.control.clock_source == ClockSource::Internal)
                 || (self.control.clock_source == ClockSource::External
-                    && self.input_byte.is_ready(rx))
+                    && self.input_byte.is_ready(rx)
+                    && ime)
             {
                 self.output_byte = self.output_byte << 1 | self.byte >> 7;
                 self.byte = (self.byte << 1) | self.input_byte.advance(rx);