diff --git a/src/bringelle.c b/src/bringelle.c
index e29ffc5..520b83d 100644
--- a/src/bringelle.c
+++ b/src/bringelle.c
@@ -3,10 +3,8 @@
 #include "core/mem.h"
 #include "core/gdt.h"
 #include "core/paging.h"
+#include "core/scheduler.h"
 
-char show_tics=0;
-
-extern GDT_TSS TSS;
 extern void interrupt_enable();
 
 void utask(){
@@ -60,19 +58,3 @@ void bringelle(){
 }
 
 
-void clock(){
-  static int tic=0;
-  static int sec=0;
-  tic++;
-  if(tic>=20){
-    tic=0;
-    sec++;
-    if(show_tics)
-      putchar('.');
-  }
-}
-
-void page_fault(){
-  print("Page fault!");
-}
-
diff --git a/src/core/gdt.h b/src/core/gdt.h
index 246ddbe..c0c9e05 100644
--- a/src/core/gdt.h
+++ b/src/core/gdt.h
@@ -62,6 +62,8 @@ typedef struct GDT_TSS {
   u16 t_reserved, io_map;
 } __attribute__((packed)) GDT_TSS;
 
+extern GDT_TSS TSS;
+
 /**
  * Copy GDT in memory
  */
diff --git a/src/core/int.S b/src/core/int.S
index 8ca8b7a..115f37c 100644
--- a/src/core/int.S
+++ b/src/core/int.S
@@ -63,8 +63,7 @@ INT_SYSCALL:
 .globl INT_PAGE_FAULT
 INT_PAGE_FAULT:
     SAVE_REGS
-    call page_fault
-    hlt
+    call paging_page_fault
     movb $0x20, %al
     outb %al, $0x20
     RESTORE_REGS
diff --git a/src/core/paging.c b/src/core/paging.c
index c32a3bc..8f12866 100644
--- a/src/core/paging.c
+++ b/src/core/paging.c
@@ -106,4 +106,9 @@ char *paging_allocate(int p){
         print("Jean\n");
     }
     print("end");
+}
+
+void paging_page_fault(){
+  print("Page fault!");
+  asm("hlt");
 }
\ No newline at end of file
diff --git a/src/core/paging.h b/src/core/paging.h
index ad3671e..1526101 100644
--- a/src/core/paging.h
+++ b/src/core/paging.h
@@ -3,19 +3,24 @@
 
 #define PAGING_CR0_BIT 0x80000000
 #define PAGING_PAGE_SIZE 4096
-#define PAGING_MAX_PAGES 2048
+#define PAGING_MAX_PAGES 2048 // At least 1024 for the kernel
 #if PAGING_MAX_PAGES%1024>0
     #define PAGING_MAX_DIR_ENTRY PAGING_MAX_PAGES/1024+1
 #else
     #define PAGING_MAX_DIR_ENTRY PAGING_MAX_PAGES/1024
 #endif
 
-/*
+/**
  * Configure and enable paging
  */
 void paging_enable();
-
+/**
+ * Allocate a new page and return its address
+ */
 char* paging_allocate_next_page();
+/**
+ * Set usage status of a page
+ */
 void paging_set_usage(int addr,char state);
 /**
  * Create a new page directory containing
@@ -23,4 +28,8 @@ void paging_set_usage(int addr,char state);
  */
 char *paging_allocate(int p);
 void paging_dump(int min,int max);
+/**
+ * Handler of page fault
+ */
+void paging_page_fault();
 #endif
\ No newline at end of file
diff --git a/src/core/scheduler.c b/src/core/scheduler.c
index e69de29..0f2b724 100644
--- a/src/core/scheduler.c
+++ b/src/core/scheduler.c
@@ -0,0 +1,20 @@
+#include "libc/stdio.h"
+
+char show_tics=0;
+
+void schedule(){
+
+}
+
+void clock(){
+  static int tic=0;
+  static int sec=0;
+  tic++;
+  if(tic>=20){
+    tic=0;
+    sec++;
+    if(show_tics)
+      putchar('.');
+  }
+  schedule();
+}
\ No newline at end of file
diff --git a/src/core/scheduler.h b/src/core/scheduler.h
index f15168b..ec0caf1 100644
--- a/src/core/scheduler.h
+++ b/src/core/scheduler.h
@@ -1,5 +1,9 @@
 #ifndef SCHEDULER_H
 #define SCHEDULER_H
 
+extern char show_tics;
+
+void clock();
+void schedule();
 
 #endif
\ No newline at end of file
diff --git a/src/libc/math.c b/src/libc/math.c
index 2051dc1..80b1d3a 100644
--- a/src/libc/math.c
+++ b/src/libc/math.c
@@ -11,4 +11,22 @@ int pow(int x,int n){
     for(int i=0;i<(n-1);i++)
         ret*=x;
     return ret;
+}
+
+int max(int x,int y){
+    if(x>y)
+        return x;
+    return y;
+}
+
+int min(int x,int y){
+    if(x<y)
+        return x;
+    return y;
+}
+
+int abs(int x){
+    if(x<0)
+        return -x;
+    return x;
 }
\ No newline at end of file
diff --git a/src/libc/math.h b/src/libc/math.h
index 56f1788..9f9bd58 100644
--- a/src/libc/math.h
+++ b/src/libc/math.h
@@ -2,5 +2,7 @@
 #define MATH_H
 
 int pow(int x,int n);
-
+int max(int x,int y);
+int min(int x,int y);
+int abs(int x);
 #endif
\ No newline at end of file