CTAOS v3

SysCore/hal/pit/pit.c

@@ -0,0 +1,56 @@
+#include <system.h>
+#include <time.h>
+#include "../irq/irq.h"
+#include "pit.h"
+
+volatile unsigned int _pit_ticks = 0;
+volatile unsigned int _pit_frequency = 0;
+unsigned char _pit_init = 0;
+volatile TIME _internal_clock;
+
+
+void i86_pit_set_frequency(int frequency)
+{
+      int divisor = 1193180/frequency;           // Calculate the divisor
+      outportb(0x43, 0x36);               // Set our command byte 0x36
+      outportb(0x40, divisor&0xFF);       // Set low byte
+      outportb(0x40, divisor>>8);         // Set high byte
+      _pit_frequency = frequency;
+}
+
+void i86_pit_handler(ISR_stack_regs *r)
+{
+      _pit_ticks++;                                  // count tick
+      if (_pit_ticks % _pit_frequency == 0)
+                  _CLOCK_INC((TIME*)&_internal_clock);   // update internal clock
+}
+
+unsigned int i86_pit_set_tick_count(unsigned int i)
+{
+      unsigned int r = _pit_ticks;
+      _pit_ticks = i;
+      return r;
+}
+
+unsigned int i86_pit_get_tick_count()
+{
+      return _pit_ticks;
+}
+unsigned int i86_pit_get_frequency()
+{
+      return _pit_frequency;
+}
+
+void i86_pit_install(int freq)
+{
+      i86_irq_install_handler(0, i86_pit_handler);
+      i86_pit_set_frequency(freq);
+      _pit_ticks = 0;
+      _pit_init = 1;
+
+}
+
+unsigned char i86_pit_is_initialized()
+{
+      return _pit_init;
+}