add timer

Makefile

@@ -27,6 +27,7 @@ KERNEL_OBJS	:=\
 	$(OBJ)/isr.o \
 	$(OBJ)/io.o \
 	$(OBJ)/monitor.o \
+	$(OBJ)/timer.o \
 	$(OBJ)/memory.o \
 	$(OBJ)/random.o \
 	$(OBJ)/main.o

include/timer.h

@@ -0,0 +1,26 @@
+#ifndef _MOROS_TIMER_H
+#define _MOROS_TIMER_H
+
+#include "monitor.h"
+#include "io.h"
+#include "isr.h"
+
+namespace MorOS
+{
+    class Timer
+    {
+    public:
+        Timer();
+        Timer(uint32_t freq);
+        ~Timer();
+
+        void init(uint32_t freq);
+        void set(uint32_t freq);
+
+        static void callback(registers_t regs);
+        static uint32_t tick;
+    }; // Timer
+
+} // MorOS
+
+#endif // _MOROS_TIMER_H

src/main.cpp

@@ -4,6 +4,7 @@
 #include "monitor.h"
 #include "gdt.h"
 #include "idt.h"
+#include "timer.h"
 #include "memory.h"
 
 extern "C" void _main(multiboot_info_t* mbd, uint32_t)
@@ -12,7 +13,7 @@ extern "C" void _main(multiboot_info_t* mbd, uint32_t)
     MorOS::Monitor monitor{};
     MorOS::GlobalDescriptorTable gdt{};
     MorOS::InterruptManager interruptManager{};
-    
+
     multiboot_memory_map_t* mmmt = 0;
 
     // cycle through the memory map in search of the memory chunk at 1MiB
@@ -31,12 +32,10 @@ extern "C" void _main(multiboot_info_t* mbd, uint32_t)
     // if we have a memory chunk at 1MiB, let's totally use it!
     if(mmmt != 0)
         MorOS::MemoryManager memoryManager(mmmt->addr_low, mmmt->len_low);
-
-    // moment of fucking truth
-    asm volatile("int $0x04;");
-    asm volatile("int $0x05;");
-    asm volatile("int $0x06;");
-    asm volatile("int $0x07;");
-
-    // hang out here forever
+
+    MorOS::Timer(100);
+
+
+    // just chill out forever!
+    while(1);
 }

src/timer.cpp

@@ -0,0 +1,52 @@
+#include "timer.h"
+
+namespace MorOS
+{
+    // define it so we can use it in the callback!
+    uint32_t Timer::tick = 0;
+
+    Timer::Timer()
+    {
+        tick = 0;
+        register_interrupt_handler(IRQ0, &MorOS::Timer::callback);
+    }
+
+    Timer::Timer(uint32_t freq)
+    {
+        tick = 0;
+        register_interrupt_handler(IRQ0, &MorOS::Timer::callback);
+        set(freq);
+    }
+    Timer::~Timer()
+    { }
+
+    void Timer::set(uint32_t freq)
+    {
+        // The value we send to the PIT is the value to divide it's input clock
+        // PIT input clock: 1193180 Hz
+
+        // divide the PIT clock speed by the frequency we want
+        // divisor must be small enough to fit into 16-bits.
+        // the higher the divisor the faster the interrupt
+        uint32_t divisor = 1193180 / freq;
+
+
+        // Send the command byte.
+        outb(0x43, 0x36);
+
+        // Divisor has to be sent byte-wise, so split here into upper/lower bytes.
+        uint8_t l = (uint8_t)(divisor & 0xFF);
+        uint8_t h = (uint8_t)( (divisor>>8) & 0xFF );
+
+        // Send the frequency divisor.
+        outb(0x40, l);
+        outb(0x40, h);
+    }
+
+    void Timer::callback(registers_t regs)
+    {
+        tick++;
+        printf("Pulse: %u\n", tick);
+    }
+
+} // MorOS