From 6789f1082a86de0d871d2e7fa68ae4a7c59bb041 Mon Sep 17 00:00:00 2001
From: mrgian <mail@gian.im>
Date: Thu, 6 Apr 2023 21:21:10 +0200
Subject: [PATCH] Implement backspace

---
 kernel/src/keyboard.rs | 32 ++++++++++++++++++++++----------
 kernel/src/print.rs    |  8 ++++++++
 2 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/kernel/src/keyboard.rs b/kernel/src/keyboard.rs
index f909969..6502d81 100644
--- a/kernel/src/keyboard.rs
+++ b/kernel/src/keyboard.rs
@@ -1,4 +1,5 @@
 use crate::pic::PICS;
+use crate::print::PRINTER;
 use core::arch::asm;
 
 pub const KEYBOARD_INT: u8 = 33;
@@ -30,14 +31,25 @@ pub extern "C" fn keyboard_handler() {
     PICS.end_interrupt(KEYBOARD_INT);
 
     unsafe {
-        if scancode == 0x2a {
-            KEYBOARD.lshift = true;
-            return;
-        }
-
-        if scancode == 0xaa {
-            KEYBOARD.lshift = false;
-            return;
+        match scancode {
+            //press left shift
+            0x2a => {
+                KEYBOARD.lshift = true;
+                return;
+            },
+
+            //release left shift
+            0xaa => {
+                KEYBOARD.lshift = false;
+                return;
+            },
+
+            //backspace
+            0x0e => {
+                PRINTER.backspace();
+                return;
+            },
+            _ => {},
         }
     }
 
@@ -65,12 +77,12 @@ fn scancode_to_char(scancode: u8) -> char {
 
     let mut key;
 
-    if index < 36 {
+    if index < chars.len() {
         key = chars[index];
 
         unsafe {
             if KEYBOARD.lshift {
-                key -= 0x20;
+                key -= 0x20; //make char uppercase
             }
         }
     } else {
diff --git a/kernel/src/print.rs b/kernel/src/print.rs
index b5e7928..cfa6b53 100644
--- a/kernel/src/print.rs
+++ b/kernel/src/print.rs
@@ -78,6 +78,14 @@ impl Printer {
         self.set_cursor_position();
     }
 
+    pub fn backspace(&mut self) {
+        self.x -= 1;
+        self.printc('\0', 12, 0);
+        self.x -= 1;
+
+        self.set_cursor_position();
+    }
+
     //get cursor position directly talking to vga hardware
     pub fn get_cursor_position(&self) -> (u16, u16) {
         let mut index: u16 = 0;