PIT

kernel/drivers/pic/pic.h

@@ -0,0 +1,7 @@
+#define PIC1_ADDR	0x20
+#define PIC2_ADDR	0xA0		
+#define PIC1_COMMAND	PIC1_ADDR
+#define PIC1_DATA	(PIC1_ADDR+1)
+#define PIC2_COMMAND	PIC2_ADDR
+#define PIC2_DATA	(PIC2_ADDR+1)
+#define PIC_EOI		0x20	

kernel/drivers/pic/pic_stubs.S

@@ -0,0 +1,51 @@
+#include "drivers/pic/pic.h"
+
+.code32
+.global init_pic
+init_pic:
+    # init command
+    mov $0x11, %al
+    outb %al, $PIC1_COMMAND
+    outb %al, $PIC2_COMMAND
+
+    # vector offsets
+    mov $0x20, %al
+    outb %al, $PIC1_DATA
+    mov $0x28, %al
+    outb %al, $PIC2_DATA
+
+    # cascade 
+    mov $0x04, %al
+    outb %al, $PIC1_DATA
+    mov $0x02, %al
+    outb %al, $PIC2_DATA 
+
+    # env
+    mov $0x01, %al
+    outb %al, $PIC1_DATA
+    outb %al, $PIC2_DATA 
+
+    # mask all 
+    mov $0xFC, %al
+    outb %al, $PIC1_DATA
+    mov $0xFF, %al
+    outb %al, $PIC2_DATA 
+
+    ret
+
+.global io_wait
+io_wait: 
+    ret
+
+.global send_eoi_master
+send_eoi_master:
+    mov $0x20, %al
+    outb %al, $PIC1_COMMAND
+    ret 
+
+.global send_eoi_slave 
+send_eoi_slave:
+    mov $0x20, %al
+    outb %al, $PIC2_COMMAND
+    call send_eoi_master
+    ret 

kernel/drivers/pit/pit_stubs.S

@@ -0,0 +1,16 @@
+#include "drivers/pit/pit.h"
+
+.code32 
+
+.global init_pit
+init_pit: # tickrate: 1193182/1000 = 0x04A9 (1000hz) (1ms)
+    movb $0x36, %al
+    outb %al, $0x43
+
+    movb $0xA9, %al
+    outb %al, $0x40
+
+    movb $0x04, %al
+    outb %al, $0x40
+
+    ret