From 4607b5aba5c7713b2bb3a6d8aaa0bfddd7dc40c1 Mon Sep 17 00:00:00 2001
From: xamidev <xamidev@riseup.net>
Date: Sun, 28 Dec 2025 11:06:33 +0100
Subject: [PATCH] holy SHIFT

---
 src/io/term.c | 27 +++++++++++++++++++--
 src/io/term.h |  1 +
 src/kbd/ps2.c | 66 ++++++++++++++++++++++++++++-----------------------
 src/kbd/ps2.h | 18 +++++++++++---
 4 files changed, 77 insertions(+), 35 deletions(-)

diff --git a/src/io/term.c b/src/io/term.c
index f2a913c..0852355 100644
--- a/src/io/term.c
+++ b/src/io/term.c
@@ -66,7 +66,19 @@ static void draw_char(char c, int px, int py, int fg, int bg)
 	}
 }
 
-static void putchar(char c)
+static void erase_char(int px, int py)
+{
+	for (size_t y=0; y<FONT_HEIGHT; y++)
+	{
+		for (size_t x=0; x<8; x++)
+		{
+			// Black
+			putpixel(px+x, py+y, 0);
+		}
+	}
+}
+
+void putchar(char c)
 {
 	if (c == '\n')
 	{
@@ -75,6 +87,17 @@ static void putchar(char c)
 		return;
 	}
 
+	// Improperly handled.
+	// When we're on an empty line it should get to the upper line's last character
+	if (c == '\b')
+	{
+		cursor.x--;
+		int px = cursor.x * FONT_WIDTH;
+		int py = cursor.y * FONT_HEIGHT;
+		erase_char(px, py);
+		return;
+	}
+
 	if ((cursor.x+1)*FONT_WIDTH >= framebuffer->width)
 	{
 		cursor.x = 0;
@@ -87,7 +110,7 @@ static void putchar(char c)
 	cursor.x++;
 }
 
-// Overhead that could be avoided, right?
+// Overhead that could be avoided, right? (for printf)
 void _putchar(char character)
 {
 	putchar(character);
diff --git a/src/io/term.h b/src/io/term.h
index c7bcf5c..a240768 100644
--- a/src/io/term.h
+++ b/src/io/term.h
@@ -3,6 +3,7 @@
 
 int term_init();
 void kputs(const char* str);
+void putchar(char c);
 
 enum TermColors
 {
diff --git a/src/kbd/ps2.c b/src/kbd/ps2.c
index 6565a71..3af8242 100644
--- a/src/kbd/ps2.c
+++ b/src/kbd/ps2.c
@@ -4,6 +4,7 @@
 #include "../io/printf.h"
 #include "ps2.h"
 #include <stdint.h>
+#include "../io/term.h"
 
 // The key status bitfield will be used to see if ALT, CONTROL, or SHIFT is pressed
 uint8_t key_status = 0b00000000;
@@ -156,50 +157,55 @@ void keyboard_handler()
     // Key release (bit 7 set)
     if (scancode & 0x80)
     {
-        if (key_status & SHIFT_PRESSED)
+        unsigned char code = scancode & 0x7F;
+        switch (code)
         {
-            serial_kputs("SHIFT was released!\n");
-            key_status &= ~(1 << 0); // Unset SHIFT bit
+            // Clear the corresponding bit if corresponding key is released
+            case LEFT_SHIFT_PRESSED:
+            case RIGHT_SHIFT_PRESSED:
+                key_status &= ~SHIFT_PRESSED_BIT;
+                break;
+            case CTRL_PRESSED:
+                key_status &= ~CTRL_PRESSED_BIT;
+                break;
+            case ALT_PRESSED:
+                key_status &= ~ALT_PRESSED_BIT;
+                break;
         }
 
-        if (key_status & ALT_PRESSED)
-        {
-            serial_kputs("ALT was released!\n");
-            key_status &= ~(1 << 1); // Unset ALT bit
-        }
-
-        if (key_status & CTRL_PRESSED)
-        {
-            serial_kputs("CTRL was released!\n");
-            key_status &= ~(1 << 2); // Unset CTRL bit
-        }
+        // Send EOI
+        outb(0x20, 0x20);
+        return;
     }
     else
     {
         // Key press
-        unsigned char character;
-
-        switch (keymap[scancode])
+        switch (scancode)
         {
-            case SHIFT:
-                serial_kputs("SHIFT ");
-                key_status |= (1 << 0); // SHIFT bit
+            // Set bits for corresponding special key press
+            case LEFT_SHIFT_PRESSED:
+            case RIGHT_SHIFT_PRESSED:
+                key_status |= SHIFT_PRESSED_BIT;
                 break;
-            case ALT:
-                serial_kputs("ALT ");
-                key_status |= (1 << 1);
+            case CTRL_PRESSED:
+                key_status |= CTRL_PRESSED_BIT;
                 break;
-            case CTRL:
-                serial_kputs("CTRL ");
-                key_status |= (1 << 2);
+            case ALT_PRESSED:
+                key_status |= ALT_PRESSED_BIT;
                 break;
+
             default:
-                character = (key_status & SHIFT_PRESSED) ? keymap_shifted[scancode] : keymap[scancode];
-                printf("%c", character);
-                break;
+            {
+                // Should we get a SHIFTED char or a regular one?
+                unsigned char c = (key_status & SHIFT_PRESSED_BIT) ? keymap_shifted[scancode] : keymap[scancode];
+
+                if (c)
+                {
+                    putchar(c);
+                }
+            }
         }
 
-        // Should we get a SHIFTED char or a regular one?
         serial_kputs("key pressed!\n");
     }
 
diff --git a/src/kbd/ps2.h b/src/kbd/ps2.h
index 2ad8457..5b1c207 100644
--- a/src/kbd/ps2.h
+++ b/src/kbd/ps2.h
@@ -3,9 +3,9 @@
 
 void keyboard_handler();
 
-#define SHIFT_PRESSED 0b00000001
-#define ALT_PRESSED   0b00000010
-#define CTRL_PRESSED  0b00000100
+#define SHIFT_PRESSED_BIT 0b00000001
+#define ALT_PRESSED_BIT   0b00000010
+#define CTRL_PRESSED_BIT  0b00000100
 
 enum SpecialKeys
 {
@@ -14,6 +14,18 @@ enum SpecialKeys
     CTRL = 253
 };
 
+enum SpecialScancodes
+{
+    LEFT_SHIFT_PRESSED = 0x2A,
+    LEFT_SHIFT_RELEASED = 0xAA,
+    RIGHT_SHIFT_PRESSED = 0x36,
+    RIGHT_SHIFT_RELEASED = 0xB6,
+    CTRL_PRESSED = 0x1D,
+    CTRL_RELEASED = 0x9D,
+    ALT_PRESSED = 0x38,
+    ALT_RELEASED = 0xB8  
+};
+
 enum KeyboardLayout
 {
     US,