From 820fa143edde3bf1ca103869dfaff8ba35e8702b Mon Sep 17 00:00:00 2001
From: James Barnett <noreply@jamesbarnett.xyz>
Date: Sun, 26 May 2019 16:39:13 +0100
Subject: Add hardware cursor support

---
 kernel/gpu/text_mode/display.c | 21 ++++++++++--
 kernel/kernel.c                | 78 ++----------------------------------------
 2 files changed, 21 insertions(+), 78 deletions(-)

diff --git a/kernel/gpu/text_mode/display.c b/kernel/gpu/text_mode/display.c
index 3659e60..19074f7 100644
--- a/kernel/gpu/text_mode/display.c
+++ b/kernel/gpu/text_mode/display.c
@@ -6,18 +6,29 @@
 
 char *video_ram = (char *) 0xB8000;
 int cursor_pos = 0;
-int char_attribute_byte = 0x07;
+int char_attribute_byte = 0x0F;
+
+extern void write_port(unsigned short port, unsigned char data);
 
 void scrn_clear()
 {
   for (int i = 0; i < FRAME_SIZE; i = i + 2)
   {
-    video_ram[i] = ' ';
+    video_ram[i] = 0;
     video_ram[i + 1] = char_attribute_byte;
   };
   cursor_pos = 0;
 }
 
+void scrn_update_csr()
+{
+    unsigned short csr = cursor_pos/2;
+    write_port(0x3D4, 14);
+    write_port(0x3D5, csr >> 8);
+    write_port(0x3D4, 15);
+    write_port(0x3D5, csr);
+}
+
 void scrn_print(char *msg)
 {
   int j = 0;
@@ -45,6 +56,7 @@ void scrn_putchar(unsigned char byte)
 {
   video_ram[cursor_pos++] = byte;
   video_ram[cursor_pos++] = char_attribute_byte;
+  scrn_update_csr();
 }
 
 // TODO - jump cursor to prev non 0 text char rather than reversing through whole array
@@ -54,6 +66,7 @@ void scrn_backspace()
   {
     video_ram[--cursor_pos] = char_attribute_byte;
     video_ram[--cursor_pos] = 0;
+    scrn_update_csr();
   }
 }
 
@@ -61,4 +74,6 @@ void scrn_newline()
 {
   int current_line = cursor_pos / COLS;
   cursor_pos = (current_line + 1) * COLS;
-}
\ No newline at end of file
+  scrn_update_csr();
+}
+
diff --git a/kernel/kernel.c b/kernel/kernel.c
index 80f110d..a6540f5 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -5,9 +5,10 @@
 
 void run_kern_demo()
 {
-  scrn_set_text_colour(COLOUR_LIGHT_GREEN, COLOUR_BLACK);
+  
   scrn_clear();
-
+  scrn_set_text_colour(COLOUR_LIGHT_GREEN, COLOUR_BLACK);
+  
   scrn_println("  _   _              ____   _____ ");
   scrn_println(" | | (_)            / __ \\ / ____|");
   scrn_println(" | |_ _ _ __  _   _| |  | | (___  ");
@@ -17,79 +18,6 @@ void run_kern_demo()
   scrn_println("               __/ |              ");
   scrn_println("              |___/               ");
 
-  scrn_println("");
-  scrn_println("Supported colours");
-  scrn_set_text_colour(COLOUR_BLUE, COLOUR_BLACK);
-  scrn_print("blue ");
-  scrn_set_text_colour(COLOUR_GREEN, COLOUR_BLACK);
-  scrn_print("green ");
-  scrn_set_text_colour(COLOUR_CYAN, COLOUR_BLACK);
-  scrn_print("cyan ");
-  scrn_set_text_colour(COLOUR_RED, COLOUR_BLACK);
-  scrn_print("red ");
-  scrn_set_text_colour(COLOUR_PURPLE, COLOUR_BLACK);
-  scrn_print("purple ");
-  scrn_set_text_colour(COLOUR_BROWN, COLOUR_BLACK);
-  scrn_print("brown ");
-  scrn_set_text_colour(COLOUR_GRAY, COLOUR_BLACK);
-  scrn_println("gray ");
-  scrn_set_text_colour(COLOUR_DARK_GREY, COLOUR_BLACK);
-  scrn_print("dark gray ");
-  scrn_set_text_colour(COLOUR_LIGHT_BLUE, COLOUR_BLACK);
-  scrn_print("light blue ");
-  scrn_set_text_colour(COLOUR_LIGHT_GREEN, COLOUR_BLACK);
-  scrn_print("light green ");
-  scrn_set_text_colour(COLOUR_LIGHT_CYAN, COLOUR_BLACK);
-  scrn_println("light cyan");
-  scrn_set_text_colour(COLOUR_LIGHT_RED, COLOUR_BLACK);
-  scrn_print("light red ");
-  scrn_set_text_colour(COLOUR_LIGHT_PURPLE, COLOUR_BLACK);
-  scrn_print("light purple ");
-  scrn_set_text_colour(COLOUR_YELLOW, COLOUR_BLACK);
-  scrn_print("yellow ");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_BLACK);
-  scrn_println("white ");
-
-  scrn_set_text_colour(COLOUR_BLACK, COLOUR_WHITE);
-  scrn_print("B");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_BLUE);
-  scrn_print("A");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_GREEN);
-  scrn_print("C");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_CYAN);
-  scrn_print("K");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_RED);
-  scrn_print("G");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_PURPLE);
-  scrn_print("R");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_BROWN);
-  scrn_print("O");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_GRAY);
-  scrn_print("U");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_LIGHT_BLUE);
-  scrn_print("N");
-  scrn_set_text_colour(COLOUR_BLACK, COLOUR_YELLOW);
-  scrn_print("D");
-  scrn_set_text_colour(COLOUR_BLACK, COLOUR_LIGHT_GREEN);
-  scrn_print(" ");
-
-  scrn_set_text_colour(COLOUR_BLACK, COLOUR_LIGHT_CYAN);
-  scrn_print("C");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_LIGHT_RED);
-  scrn_print("O");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_LIGHT_PURPLE);
-  scrn_print("L");
-  scrn_set_text_colour(COLOUR_BLACK, COLOUR_WHITE);
-  scrn_print("O");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_RED);
-  scrn_print("U");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_PURPLE);
-  scrn_print("R");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_BROWN);
-  scrn_print("S");
-  scrn_set_text_colour(COLOUR_WHITE, COLOUR_GRAY);
-  scrn_print("!");
-
   scrn_set_text_colour(COLOUR_WHITE, COLOUR_BLACK);
   scrn_newline();
 }
-- 
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