From 788afa49d4044d22fe6ec51b8e12917ebc481015 Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Wed, 22 Feb 2023 10:09:32 +1100
Subject: [PATCH] fix serial

---
 src/processor/memory/mmio/serial.rs | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/processor/memory/mmio/serial.rs b/src/processor/memory/mmio/serial.rs
index 606f2f2..1fe785e 100644
--- a/src/processor/memory/mmio/serial.rs
+++ b/src/processor/memory/mmio/serial.rs
@@ -32,7 +32,8 @@ impl Default for SerialControl {
 
 pub struct Serial {
     byte: u8,
-    bits_transferred: u8,
+    output_byte: u8,
+    bits_remaining: u8,
     control: SerialControl,
 }
 
@@ -41,11 +42,13 @@ impl Serial {
         let mut will_interrupt = false;
         for _ in 0..steps {
             if self.control.transfer_in_progress {
-                let (remainder, finished) = self.bits_transferred.overflowing_sub(1);
-                self.bits_transferred = if finished {
+                self.output_byte = self.output_byte << 1 | self.byte >> 7;
+                self.byte = (self.byte << 1) | 0b1;
+                let (remainder, finished) = self.bits_remaining.overflowing_sub(1);
+                self.bits_remaining = if finished {
                     self.control.transfer_in_progress = false;
                     will_interrupt = true;
-                    print!("{}", self.byte as char);
+                    print!("{}", self.output_byte as char);
                     stdout().flush().unwrap();
                     7
                 } else {
@@ -91,8 +94,9 @@ impl Serial {
 impl Default for Serial {
     fn default() -> Self {
         Self {
-            byte: 0,
-            bits_transferred: 7,
+            byte: 0xFF,
+            output_byte: 0,
+            bits_remaining: 7,
             control: SerialControl::default(),
         }
     }