PIT

kernel/boot/boot.S

@@ -21,8 +21,6 @@ stack_top:
 .type _start, @function
 _start:
 	mov $stack_top, %esp
-	call kernel_main
-
-	cli
-1:	hlt
+	call kmain
+1:
 	jmp 1b

kernel/common_stubs.S

@@ -0,0 +1,6 @@
+.code32 
+
+.global enable_interrupts
+enable_interrupts:
+    sti 
+    ret

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

kernel/interrupts.c

@@ -1,7 +1,8 @@
 #include "lib/print.h"
 #include <stdint.h>
 
-extern void master_eoi(void);
+extern void send_eoi_master(void);
+extern void send_eoi_slave(void);
 
 struct registers {
     uint32_t edi, esi, ebp, esp_dummy, ebx, edx, ecx, eax;
@@ -32,12 +33,12 @@ void common_interrupt_handler(struct registers *regs) {
             kprint("\n");
             break;
         case 32:
-            // wake the PIC timer driver
-            master_eoi();
+            // wake the PIT timer driver
+            send_eoi_master();
             break;
         case 33:    
-            // wake the keyboard driver
-            master_eoi();
+            kprint("keypress detected\n");
+            send_eoi_master();
             break;
         default:
             kprint("Received unhandled interrupt\n");

kernel/kmain.c

@@ -7,8 +7,11 @@
 
 extern void init_idt();
 extern void init_gdt();
+extern void init_pic();
+extern void init_pit();
+extern void enable_interrupts();
 
-void kernel_main(void) 
+void kmain(void) 
 {
   extern print_stream_t vga_print_stream;
   extern print_stream_t* kout;
@@ -22,4 +25,15 @@ void kernel_main(void)
 
   init_idt();
   kprint("IDT set\n");
+
+  init_pic();
+  kprint("PIC initialized\n");
+
+  init_pit();
+  kprint("PIT initialized\n");
+
+  enable_interrupts();
+  kprint("Interrupts enabled\n");
+
+  while(1);
 }