From e03b2ed579e84967648796897bd8aaf4256319e9 Mon Sep 17 00:00:00 2001
From: Freya Murphy <freya@freyacat.org>
Date: Sun, 20 Apr 2025 19:56:27 -0400
Subject: PIT (timer)

---
 kernel/drivers/pit.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 kernel/drivers/pit.c

(limited to 'kernel/drivers/pit.c')

diff --git a/kernel/drivers/pit.c b/kernel/drivers/pit.c
new file mode 100644
index 0000000..cb3c091
--- /dev/null
+++ b/kernel/drivers/pit.c
@@ -0,0 +1,23 @@
+#include <comus/asm.h>
+#include <comus/drivers/pit.h>
+
+#define CHAN_0 0x40
+#define CHAN_1 0x41
+#define CHAN_2 0x42
+#define CMD 0x43
+
+uint64_t ticks = 0;
+
+uint16_t pit_read_divider(void) {
+	uint16_t count = 0;
+	cli();
+	outb(CMD, 0); // clear bits
+	count = inb(CHAN_0); // low byte
+	count |= inb(CHAN_0)<<8; // highbyte
+	return count;
+}
+
+void pit_set_divider(uint16_t count) {
+	outb(CHAN_0, count & 0xFF); // low byte
+	outb(CHAN_0, (count & 0xFF00) >> 8); // high byte
+}
-- 
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