--- a/cos/Makefile	Tue Dec 27 13:31:38 2011 +0100
+++ b/cos/Makefile	Tue Dec 27 17:36:52 2011 +0100
@@ -27,6 +27,7 @@
 	kernel/klib.o \
 	kernel/malloc.o \
 	kernel/task.o \
+	kernel/mm.o \
 	kernel/timer.o
 
 lcfosc.bin: $(CRT0) $(OBJECTS) linker.ld

--- a/cos/kernel/handlers.c	Tue Dec 27 13:31:38 2011 +0100
+++ b/cos/kernel/handlers.c	Tue Dec 27 17:36:52 2011 +0100
@@ -57,13 +57,11 @@
 
 void setupIDT(void) {
   int i;
-  //panic("Just before filling IDT");
-  // After this line a crash occurs!
+
   // Fill all vectors with the default handler:
   for (i=0; i<256; i++) {
     setIDTentry(i, INTDEF, 0x08, 0x8E);
   }
-  //panic("Just after setting defhandlers in IDT");
 
   // Now set other then default handler:
   setIDTentry(0, INT0, 0x08, 0x8E);
@@ -96,11 +94,9 @@
   idtP.base = (uint64_t)idt;
   idtP.limit = (sizeof(IDT_entry) * 256) - 1;
   // call load IDT asm function:
-  //panic("Just before LIDT");
   loadIDT();
 
   PICremap();
-  //panic("Just before sti");
   asm("sti");
 }
 

--- a/cos/kernel/kernel.c	Tue Dec 27 13:31:38 2011 +0100
+++ b/cos/kernel/kernel.c	Tue Dec 27 17:36:52 2011 +0100
@@ -20,19 +20,13 @@
    kfree(a);
 }
 
-void reboot()
-{
-   while ( (inb(0x64) & 0x02) == 0x02)
-   {
-      ;
-   }
-   outb(0x64, 0xFE);
-}
+// A test program that prints 'Hoi' to the screen:
+unsigned char hello_program[] = {0x55, 0x48, 0x89, 0xe5, 0x48, 0x83, 0xec, 0x10, 0x48, 0xc7, 0x45, 0xf8, 0x0, 0x80, 0xb, 0x0, 0x48, 0x8b, 0x45, 0xf8, 0xc6, 0x0, 0x48, 0x48, 0x8b, 0x45, 0xf8, 0x48, 0x83, 0xc0, 0x2, 0xc6, 0x0, 0x6f, 0x48, 0x8b, 0x45, 0xf8, 0x48, 0x83, 0xc0, 0x4, 0xc6, 0x0, 0x69, 0xeb, 0xfe, 0x0, 0x14, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x7a, 0x52, 0x0, 0x1, 0x78, 0x10, 0x1, 0x1b, 0xc, 0x7, 0x8, 0x90, 0x1, 0x0, 0x0, 0x1c, 0x0, 0x0, 0x0, 0x1c, 0x0, 0x0, 0x0, 0xb0, 0xff, 0xff, 0xff, 0x2f, 0x0, 0x0, 0x0, 0x0, 0x41, 0xe, 0x10, 0x86, 0x2, 0x43, 0xd, 0x6, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0};
 
 void kmain()
 {
   init_screen();
-  setupIDT(); // This causes error on real hardware
+  setupIDT(); 
   init_heap();
 
   printf("Welcome!\n");

--- a/cos/kernel/kernel.h	Tue Dec 27 13:31:38 2011 +0100
+++ b/cos/kernel/kernel.h	Tue Dec 27 17:36:52 2011 +0100
@@ -66,6 +66,7 @@
 // Panic exit:
 void halt(void);
 void panic(char *msg);
+void reboot(void);
 
 // Bochs xchg bx,bx breakpoint:
 void magicBochsBreak();

--- a/cos/kernel/klib.c	Tue Dec 27 13:31:38 2011 +0100
+++ b/cos/kernel/klib.c	Tue Dec 27 17:36:52 2011 +0100
@@ -8,6 +8,15 @@
    halt();
 }
 
+void reboot()
+{
+   while ( (inb(0x64) & 0x02) == 0x02)
+   {
+      ;
+   }
+   outb(0x64, 0xFE);
+}
+
 // IO port helpers:
 void outb(uint16_t port, uint8_t value)
 {

--- a/cos/kernel/malloc.c	Tue Dec 27 13:31:38 2011 +0100
+++ b/cos/kernel/malloc.c	Tue Dec 27 17:36:52 2011 +0100
@@ -22,9 +22,8 @@
    Kernelpanic in case of failure..
 */
 
-void* kmalloc(uint64_t size) {
-   // printf("Malloc %d bytes\n", size);
-
+void* kmalloc(uint64_t size) 
+{
    // Start at the beginning of our heap and search a free block:
    heap_t *current = kernel_heap;
    while (current->magic == HEAP_MAGIC)
@@ -63,7 +62,8 @@
    return 0x0;
 }
 
-void kfree(void* ptr) {
+void kfree(void* ptr) 
+{
   printf("Free address %x\n", ptr);
 }
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cos/kernel/mm.c	Tue Dec 27 17:36:52 2011 +0100
@@ -0,0 +1,63 @@
+
+/* Memory manager */
+
+#include "kernel.h"
+
+// BITMAP functions:
+#define NFRAMES 1000
+// Bit mask to check what frames are in use and which are free:
+uint64_t frames[NFRAMES]; // NFRAMES*64*4kB frames.
+
+void set_frame(uint64_t frame)
+{
+   uint64_t idx = frame / 64;
+   uint64_t off = frame % 64;
+   frames[idx] |= (0x1 << off);
+}
+
+void clear_frame(uint64_t frame)
+{
+   uint64_t idx = frame / 64;
+   uint64_t off = frame % 64;
+   frames[idx] &= ~(0x1 << off);
+}
+
+uint64_t test_frame(uint64_t frame)
+{
+   uint64_t idx = frame / 64;
+   uint64_t off = frame % 64;
+   return (frames[idx] & (0x1 << off));
+}
+
+uint64_t first_frame()
+{
+   uint64_t i, j;
+   for (i = 0; i < NFRAMES / 64; i++)
+   {
+      if (frames[i] != 0xFFFFFFFFFFFFFFFF)
+      {
+         for (j = 0; j < 64; j++)
+         {
+            uint64_t dut = 0x1 << j;
+            if ((frames[i] & dut) != dut)
+            {
+               return i*64+j;
+            }
+         }
+      }
+   }
+   return 0xFFFFFFFFFFFFFFFF;
+}
+
+// Memory manager functions:
+void alloc_frame()
+{
+   uint64_t idx = first_frame();
+   if (idx == (uint64_t) -1)
+   {
+      panic("No more memory!");
+   }
+   set_frame(idx);
+}
+
+