Merge pull request #23 from E-Almqvist/dev

VGA & Strings

Makefile

@@ -3,6 +3,8 @@ all: os-image
 run: all
 	qemu-system-x86_64 os-image
 
+drun: clean run
+
 grub: eOS.iso
 	qemu-system-x86_64 eOS.iso
 
@@ -32,4 +34,3 @@ clean:
 
 kernel.dis : kernel.bin
 	ndisasm -b 32 $< > $@
-

TODO.md

@@ -0,0 +1,3 @@
+# TO DO 
+ - Multiboot support (for grub etc)
+ - Expand os-image so there is no error 0x8b00!

src/kernel/kernel.c

@@ -4,7 +4,8 @@ void main() {
 	// Do kernel stuff
 	char* vidmem = (char*)0xb8000;
 	*vidmem = 'X';
-	for( int i = 0; i < 16; i++ ) {
-		println("C-Printing test!", 16);
-	}
+
+	clear_screen();
+	set_cursor_pos(24, 0);
+	println("\t eOS Version 0.0 2021", 0xf0);
 }

src/kernel/lib/string.c

@@ -0,0 +1,8 @@
+// Generic String Library
+#define INDEX(s, c) (int)(c-s) 
+
+unsigned int length(char* str) {
+	char* p;
+	for( p = str; *p != '\0'; p++ ) {}
+	return (unsigned int)(p-str);
+}

src/kernel/lib/vga.c

@@ -3,20 +3,52 @@
 // VGA base address: 0xb8000
 // Charpos = 0xb8000 + 2(row*80 + col)
 
+// Memory
 #define VIDEO_MEM 	(char*)0xb8000
-#define GET_INDEX(s, c) (int)(c-s)
-static int cursor_y = 0;
+#define VIDEO_MEM_MAX	(char*)0xb8fa0
 
-char* get_cursor_pos(unsigned int col, unsigned int row) { 
+// Global
+static unsigned int cursor_row = 0;
+static unsigned int cursor_col = 0;
+
+/*
+	VGA & Memory Functions
+*/
+char* get_vga_charpos_pointer(unsigned int col, unsigned int row) { 
 	return (char*)(VIDEO_MEM + 2*((row*80) + col)); 
 }
 
-void print(char* str, unsigned int str_len) {
+void putc(char c, unsigned int col, unsigned int row, int colorcode) {
+	char* mem = get_vga_charpos_pointer(col, row);
+	*mem = c; 		// Write the character
+	*(mem+1) = colorcode;	// Write the colorcode
+
+}
+
+/*
+	Graphics Functions
+*/
+void clear_screen() {
+	// Make all the characters spaces
+	for( char* c = VIDEO_MEM; c <= VIDEO_MEM_MAX; c += 2 )
+		*c = 0x20;
+}
+
+
+/*
+	General Printing Functions
+*/
+void set_cursor_pos(unsigned int x, unsigned int y) {
+	cursor_col = x;
+	cursor_row = y;
+}
+
+void print(char* str, int colorcode) {
 	for( char* c = str; *c != '\0'; c++ ) 
-		*get_cursor_pos( GET_INDEX(str, c), cursor_y ) = *c;
+		putc(*c, (unsigned int)(c - str) + cursor_col, cursor_row, colorcode);
 }
 
-void println(char* str, unsigned int str_len) {
-	print(str, str_len);
-	cursor_y++; // Increment to next y-pos (newline)
+void println(char* str, int colorcode) {
+	print(str, colorcode);
+	cursor_row++; // Increment to next y-pos (newline)
 }