Merge pull request #26 from E-Almqvist/dev

Ports I/O

Makefile

@@ -24,7 +24,7 @@ os-image: bootloader/bootloader.bin kernel.bin
 kernel.bin: kernel/kernel_entry.o $(OBJ) 
 	gcc -o $@ $^ -Wl,--oformat=binary -ffreestanding -nostdlib -shared -Ttext 0x1000 -m32
 
-%.o : %.c
+%.o : %.c ${HEADERS}
 	gcc -fno-pie -m32 -Os -ffreestanding -c $< -o $@
 
 %.o : %.asm

TODO.md

@@ -1,6 +1,4 @@
 # TO DO 
- - Refactor Makefile
- - Refactor file structure
  - Finish the book!
  - Multiboot support (for grub etc)
  - VGA Library (Graphics)

drivers/vga.h

@@ -0,0 +1,8 @@
+char* get_vga_charpos_pointer(unsigned int col, unsigned int row);
+void writechar(char c, unsigned int col, unsigned int row, int colorcode);
+void clear_screen();
+void disable_cursor();
+void set_cursor_pos();
+void print();
+void println();
+void vga_init();

kernel/io.c

@@ -0,0 +1,26 @@
+// Function to read a byte from port
+unsigned char port_byte_in(unsigned short port) {
+	unsigned char res;
+	__asm__("in %%dx, %%al" : "=a" (res) : "d" (port));
+
+	return res;
+}
+
+// to write a byte to port
+void port_byte_out(unsigned short port, unsigned char data) {
+	__asm__("out %%al, %%dx" : :"a" (data), "d" (port));	
+}
+
+
+// Read word from port
+unsigned short port_word_in(unsigned short port) {
+	unsigned short res;
+	__asm__("in %%dx, %%ax" : "=a" (res) : "d" (port));
+
+	return res;
+}
+
+// write word to port
+void port_word_out(unsigned short port, unsigned short data) {
+	__asm__("out %%ax, %%dx" : :"a" (data), "d" (port));
+}

kernel/io.h

@@ -0,0 +1,5 @@
+unsigned char port_byte_in();
+void port_byte_out();
+
+unsigned short port_word_in();
+void port_word_out();

kernel/kernel.c

@@ -1,3 +1,5 @@
+#include "../drivers/vga.h"
+
 void main() {
 	vga_init(); 	// Initialize the screen first
 			// i.e. clear the screen et cetera.