From 1215e39086ac29eea0f7ccc1a8ffd776f068e2d3 Mon Sep 17 00:00:00 2001
From: Arnau478 <arnauxabia@gmail.com>
Date: Fri, 17 Jun 2022 12:28:24 +0200
Subject: [PATCH] Basic VGA driver

---
 src/kernel/drivers/vga.c |  9 ++++++++
 src/kernel/drivers/vga.h | 45 ++++++++++++++++++++++++++++++++++++++++
 src/kernel/main.c        |  8 ++++---
 3 files changed, 59 insertions(+), 3 deletions(-)
 create mode 100644 src/kernel/drivers/vga.c
 create mode 100644 src/kernel/drivers/vga.h

diff --git a/src/kernel/drivers/vga.c b/src/kernel/drivers/vga.c
new file mode 100644
index 0000000..2ed09f0
--- /dev/null
+++ b/src/kernel/drivers/vga.c
@@ -0,0 +1,9 @@
+#include "vga.h"
+
+void set_char(int x, int y, char c){
+    VGA_MEMORY[(x+y*VGA_WIDTH)*2] = c;
+}
+
+void set_color(int x, int y, uint8_t color){
+    VGA_MEMORY[(x+y*VGA_WIDTH)*2+1] = color;
+}
diff --git a/src/kernel/drivers/vga.h b/src/kernel/drivers/vga.h
new file mode 100644
index 0000000..212ad6b
--- /dev/null
+++ b/src/kernel/drivers/vga.h
@@ -0,0 +1,45 @@
+#pragma once
+
+#include <stdint.h>
+
+#define VGA_MEMORY ((char *)0xB8000)
+
+#define VGA_COLOR_FG_BLACK 0x00
+#define VGA_COLOR_FG_BLUE 0x01
+#define VGA_COLOR_FG_GREEN 0x02
+#define VGA_COLOR_FG_CYAN 0x03
+#define VGA_COLOR_FG_RED 0x04
+#define VGA_COLOR_FG_PINK 0x05
+#define VGA_COLOR_FG_ORANGE 0x06
+#define VGA_COLOR_FG_WHITE 0x07
+#define VGA_COLOR_FG_LIGHT_BLACK 0x08
+#define VGA_COLOR_FG_LIGHT_BLUE 0x09
+#define VGA_COLOR_FG_LIGHT_GREEN 0x0A
+#define VGA_COLOR_FG_LIGHT_CYAN 0x0B
+#define VGA_COLOR_FG_LIGHT_RED 0x0C
+#define VGA_COLOR_FG_LIGHT_PINK 0x0D
+#define VGA_COLOR_FG_LIGHT_ORANGE 0x0E
+#define VGA_COLOR_FG_LIGHT_WHITE 0x0F
+
+#define VGA_COLOR_BG_BLACK 0x00
+#define VGA_COLOR_BG_BLUE 0x10
+#define VGA_COLOR_BG_GREEN 0x20
+#define VGA_COLOR_BG_CYAN 0x30
+#define VGA_COLOR_BG_RED 0x40
+#define VGA_COLOR_BG_PINK 0x50
+#define VGA_COLOR_BG_ORANGE 0x60
+#define VGA_COLOR_BG_WHITE 0x70
+#define VGA_COLOR_BG_LIGHT_BLACK 0x80
+#define VGA_COLOR_BG_LIGHT_BLUE 0x90
+#define VGA_COLOR_BG_LIGHT_GREEN 0xA0
+#define VGA_COLOR_BG_LIGHT_CYAN 0xB0
+#define VGA_COLOR_BG_LIGHT_RED 0xC0
+#define VGA_COLOR_BG_LIGHT_PINK 0xD0
+#define VGA_COLOR_BG_LIGHT_ORANGE 0xE0
+#define VGA_COLOR_BG_LIGHT_WHITE 0xF0
+
+#define VGA_WIDTH 80
+#define VGA_HEIGHT 25
+
+void set_char(int x, int y, char c);
+void set_color(int x, int y, uint8_t color);
diff --git a/src/kernel/main.c b/src/kernel/main.c
index 52099ad..92b2867 100644
--- a/src/kernel/main.c
+++ b/src/kernel/main.c
@@ -1,7 +1,9 @@
 #include <stdint.h>
-#include "arch/i686/io.h"
+#include "drivers/vga.h"
 
 void __attribute__((cdecl)) kmain(uint64_t magic, uint64_t addr){
-    char *mem = (char *)0xB8000; // Screen memory address (when on text mode)
-    for(int i = 0; 1; i++) mem[i] = 88; // Fill screen with Blue 'X' characters over pink background 
+    // Print a light cyan 'X' over green on the top left corner
+    set_char(0, 0, 'X');
+    set_color(0, 0, VGA_COLOR_BG_GREEN | VGA_COLOR_FG_LIGHT_CYAN);
+    for(;;); // Halt here 
 }