From ecf636f2797647d5dfc38a4562cae53fe275217d Mon Sep 17 00:00:00 2001
From: Nic Gaffney <gaffney_nic@protonmail.com>
Date: Tue, 6 Feb 2024 04:58:35 -0600
Subject: Interrupts + basic keyboard driver

---
 src/kernel/keyboard/isr.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 src/kernel/keyboard/isr.c

(limited to 'src/kernel/keyboard/isr.c')

diff --git a/src/kernel/keyboard/isr.c b/src/kernel/keyboard/isr.c
new file mode 100644
index 0000000..223bf9f
--- /dev/null
+++ b/src/kernel/keyboard/isr.c
@@ -0,0 +1,49 @@
+#include "asm.h"
+#include "print.h"
+#include "str.h"
+#include <stdint.h>
+static uint8_t shift_held = 0;
+static uint8_t capslock = 0;
+
+void keyboard_handler() {
+    const char *scancodes =
+        "??1234567890-=?\tqwertyuiop[]\n?asdfghjkl;'`?\\zxcvbnm,./?*? ";
+    const char *SCANCODES =
+        "\?\?!@#$%^&*()_+?\tQWERTYUIOP{}\n?ASDFGHJKL:\"~?|ZXCVBNM<>??*? ";
+
+    unsigned char sc = inb(0x60);
+
+    uint8_t isheld = shift_held != 0;
+    char c = ((isheld | capslock) & !(isheld & capslock)) ? SCANCODES[sc]
+                                                          : scancodes[sc];
+
+    if (capslock & (!isheld) && !isalpha(c))
+        c = scancodes[sc];
+    if (isheld && !isalpha(c))
+        c = SCANCODES[sc];
+
+    if (sc < 0x59 && scancodes[sc] != '?')
+        printf("%c", c);
+
+    switch (sc) {
+    case 0x2A:
+        shift_held |= 0b10;
+        break;
+    case 0x36:
+        shift_held |= 0b01;
+        break;
+    case 0xAA:
+        shift_held &= 0b01;
+        break;
+    case 0xB6:
+        shift_held &= 0b10;
+        break;
+    case 0x0E:
+        delete_char();
+        break;
+    case 0x3A:
+        capslock = !capslock;
+        break;
+    }
+    outb(0x20, 0x20);
+}
-- 
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