finished PIT implementation

src/OSDev_18/include/kernel/pit.h

@@ -0,0 +1,25 @@
+#ifndef PIT_H
+#define PIT_H
+
+#include <libc/stdint.h>
+#include <libc/stdbool.h>
+
+#define PIT_CMD_PORT 0x43
+#define PIT_CHANNEL0_PORT 0x40
+#define PIT_CHANNEL1_PORT 0x41
+#define PIT_CHANNEL2_PORT 0x42
+#define PC_SPEAKER_PORT 0x61
+#define PIT_DEFAULT_DIVISOR 0x4E20 //20000, gets just shy of 60Hz
+#define PIC1_CMD_PORT 0x20
+#define PIC1_DATA_PORT 0x21
+#define PIT_BASE_FREQ 1193180
+#define TARGET_FREQ 1000
+#define DIVIDER (PIT_BASE_FREQ / TARGET_FREQ)
+#define TICKS_PER_MS (TARGET_FREQ / TARGET_FREQ) // = 1, needed for converting ms into ticks
+
+void PitInitialize();
+void SleepInterrupt(uint32_t ticks);
+void SleepBusy(uint32_t milliseconds);
+void SleepTest();
+
+#endif