1 files changed, 40 insertions, 0 deletions
diff --git a/asm/asm_pit.s b/asm/asm_pit.s
new file mode 100644
index 0000000..8e16d0b
--- /dev/null
+++ b/asm/asm_pit.s
@@ -0,0 +1,40 @@
+.global asm_pit_init
+.global asm_pit_tick
+.global asm_pit_get_ticks
+
+ticks:
+.int 0
+
+asm_pit_get_ticks:
+    
+    mov (ticks),%eax
+    ret
+
+asm_pit_tick:
+
+    push %eax // persist
+
+    // INC TICK COUNTER
+    mov $ticks, %eax    
+    incl (%eax)
+
+    pop %eax // load original
+    
+    ret
+
+asm_pit_init:
+
+    // configure ticking 25 times a second
+    // 1193180 / 25 = 47727.2
+    mov $47727, %dx
+
+    mov $0b00110100, %al
+    outb %al,$0x43
+
+    mov %dx,%ax
+
+    out %al, $0x40
+    xchg %ah,%al
+    out %al, $0x40
+
+    ret