From 5827e349b3ffb73a154aa5c168d026437d1360ab Mon Sep 17 00:00:00 2001
From: sbosse <sbosse@uni-bremen.de>
Date: Wed, 22 Jan 2025 12:18:11 +0100
Subject: [PATCH] Wed 22 Jan 12:17:36 CET 2025

---
 kernel/clock.c | 35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/kernel/clock.c b/kernel/clock.c
index 8d7c504..f828217 100644
--- a/kernel/clock.c
+++ b/kernel/clock.c
@@ -11,18 +11,32 @@ See the file LICENSE for details.
 
 // Minimum PIT frequency is 18.2Hz.
 #define CLICKS_PER_SECOND 20
+#define CLICKS_MILLITIME 1/CLICKS_PER_SECOND
 
-#define TIMER0		0x40
-#define TIMER_MODE	0x43
-#define SQUARE_WAVE     0x36
-#define TIMER_FREQ	1193182
-#define TIMER_COUNT	(((unsigned)TIMER_FREQ)/CLICKS_PER_SECOND)
+#define TIMER0		    0x40
+#define TIMER_MODE	  0x43
+#define SQUARE_WAVE   0x36
+#define TIMER_FREQ	  1193182
+#define TIMER_COUNT	  (((unsigned)TIMER_FREQ)/CLICKS_PER_SECOND)
 
 static uint32_t clicks = 0;
 static uint32_t seconds = 0;
 
 static struct list queue = { 0, 0 };
 
+static unsigned long read_pit_counter(void) {
+	unsigned long count = 0;
+	// Disable interrupts
+	// cli();
+	// al = channel in bits 6 and 7, remaining bits clear
+	outb(0b0000000,TIMER_MODE);
+	
+	count = inb(TIMER0);		// Low byte
+	count |= inb(TIMER0)<<8;		// High byte
+	
+	return count;
+}
+
 static void clock_interrupt(int i, int code)
 {
 	clicks++;
@@ -67,6 +81,10 @@ void clock_wait(uint32_t millis)
 	} while(total < millis);
 }
 
+#ifdef KERNEL_CLOCK_EXT
+  #include "kernel_clock_ext.c"
+#endif
+
 void clock_init()
 {
 	outb(SQUARE_WAVE, TIMER_MODE);
@@ -76,5 +94,10 @@ void clock_init()
 	interrupt_register(32, clock_interrupt);
 	interrupt_enable(32);
 
-	printf("clock: ticking\n");
+
+#ifdef KERNEL_CLOCK_EXT
+  CLOCKINITMESSAGE
+#else
+	printf("clock: ticking %d %% %d\n",read_pit_counter(),TIMER_COUNT);
+#endif
 }