From 732e660a3741350df34cf208786dfdcce6c8f084 Mon Sep 17 00:00:00 2001
From: Kevin Lange <kevin.lange@dakko.us>
Date: Sat, 22 Oct 2011 19:32:03 -0500
Subject: [PATCH] [kbd] Clean up the keyboard a bit.

---
 kernel/core/kbd.c | 51 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 41 insertions(+), 10 deletions(-)

diff --git a/kernel/core/kbd.c b/kernel/core/kbd.c
index 1d3f6033..9b70e16a 100644
--- a/kernel/core/kbd.c
+++ b/kernel/core/kbd.c
@@ -9,6 +9,13 @@
 
 #include <system.h>
 
+#define KEY_UP_MASK   0x80
+#define KEY_CODE_MASK 0x7F
+#define KEY_CTRL_MASK 0x40
+
+#define KEY_DEVICE    0x60
+#define KEY_PENDING   0x64
+
 /* A bit-map to store the keyboard states */
 struct keyboard_states {
 	uint32_t shift : 1;
@@ -97,9 +104,15 @@ char kbd_us_l2[128] = {
 };
 
 
-
+/*
+ * "Normal" key handler
+ * Used for visible text keys and handles
+ * application of shift/alt/control
+ *
+ * Shells out to putch() to do most of the work.
+ */
 void norm(int scancode) {
-	if (scancode & 0x80) {
+	if (scancode & KEY_UP_MASK) {
 		return;
 	}
 	if (!kbd_us[scancode]) {
@@ -108,7 +121,7 @@ void norm(int scancode) {
 	if (keyboard_state.shift) {
 		putch(kbd_us_l2[scancode]);
 	} else if (keyboard_state.ctrl) {
-		int out = (int)(kbd_us_l2[scancode] - 0x40);
+		int out = (int)(kbd_us_l2[scancode] - KEY_CTRL_MASK);
 		if (out < 0 || out > 0x1F) {
 			putch(kbd_us[scancode]);
 		} else {
@@ -119,28 +132,44 @@ void norm(int scancode) {
 	}
 }
 
+/*
+ * Toggle Shift
+ */
 void shft(int scancode) {
 	keyboard_state.shift ^= 1;
 }
 
+/*
+ * Toggle Alt
+ */
 void altk(int scancode) {
 	keyboard_state.alt ^= 1;
 }
 
+/*
+ * Toggle Control
+ */
 void ctlk(int scancode) {
 	keyboard_state.ctrl ^= 1;
-	
 }
 
+/*
+ * Function keys
+ */
 void func(int scancode) {
-	if (scancode & 0x80) {
+	if (scancode & KEY_UP_MASK) {
 		return;
 	}
 	kprintf("[NOTICE] Function key %d pressed\n", scancode);
 }
 
+/*
+ * "Special" keys
+ * Extra keys on your keyboard will produce these
+ * sorts of key presses.
+ */
 void spec(int scancode) {
-	if (scancode & 0x80) {
+	if (scancode & KEY_UP_MASK) {
 		return;
 	}
 	switch (scancode) {
@@ -197,13 +226,13 @@ keyboard_handler(
 		struct regs *r
 		) {
 	unsigned char scancode;
-	scancode = inportb(0x60);
+	scancode = inportb(KEY_DEVICE);
 	if (keyboard_direct_handler) {
 		keyboard_direct_handler(scancode);
 		return;
 	}
 	keyboard_handler_t handler;
-	handler = key_method[(int)scancode & 0x7f];
+	handler = key_method[(int)scancode & KEY_CODE_MASK];
 	if (handler) {
 		handler(scancode);
 	}
@@ -219,7 +248,7 @@ keyboard_install() {
 
 void
 keyboard_wait() {
-	while(inportb(0x64) & 2);
+	while(inportb(KEY_PENDING) & 2);
 }
 
 /*
@@ -232,7 +261,8 @@ putch(
 	if (keyboard_buffer_handler) {
 		keyboard_buffer_handler(c);
 	} else {
-		if (c == 3) {
+		if (c == 3 /* ^L */) {
+			/* Find the next task that isn't the kernel and kill it */
 			__volatile__ task_t * prev_task = current_task;
 			while (current_task && !current_task->id) {
 				current_task = current_task->next;
@@ -241,6 +271,7 @@ putch(
 				kprintf("Killing task %d!\n", current_task->id);
 				kexit(1);
 			} else {
+				/* The only available task /is/ the kernel. Run away! */
 				current_task = prev_task;
 			}
 			return;