From 782cfaa0e3f44f8c8089a7c6a148149bece0a515 Mon Sep 17 00:00:00 2001
From: Benji Dial <benji6283@gmail.com>
Date: Sun, 24 Jan 2021 19:45:53 -0500
Subject: making keyboard driver spin by checking if scanbyte has changed
 rather than by a decrement loop

---
 src/kernel/kbd.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

(limited to 'src/kernel/kbd.c')

diff --git a/src/kernel/kbd.c b/src/kernel/kbd.c
index 29c0350..f7158bb 100644
--- a/src/kernel/kbd.c
+++ b/src/kernel/kbd.c
@@ -78,11 +78,15 @@ void init_kbd() {
   drives->free_file(drives, stf);
 }
 
+static uint8_t last_code_byte = 0;
 
 static inline uint8_t get_next_code_byte() {
-  for (uint32_t spin = 0; spin < 10000000; ++spin)
-    ;
-  return inb(PS2_DATA);
+  uint8_t cb;
+  do
+    cb = inb(PS2_DATA);
+  while (cb == last_code_byte);
+  last_code_byte = cb;
+  return cb;
 }
 
 static enum key_modifiers_t keymods = 0;
@@ -90,6 +94,7 @@ static enum key_modifiers_t keymods = 0;
 void on_kbd_isr() {
 //logf(LOG_INFO, "on_kbd_isr()");
   while (inb(PS2_CMD) & PS2S_CODE_READY) {
+    last_code_byte = 0;
     uint8_t code[256];
     uint8_t code_i = 0;
   sub_table:
-- 
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