From 39713a3736145483dd3310c3605f940ca34f05c3 Mon Sep 17 00:00:00 2001
From: Loic Guegan <manzerbredes@mailbox.org>
Date: Mon, 12 Apr 2021 10:13:21 +0200
Subject: Refactoring

---
 src/Makefile            |  4 +-
 src/boot/multiboot.c    |  1 -
 src/boot/multiboot.h    |  5 ++-
 src/bringelle.c         | 14 +++----
 src/core/asm.h          | 13 +++++++
 src/core/framebuffer.c  | 58 +++++++++++++++++++++++++++++
 src/core/framebuffer.h  | 35 +++++++++++++++++
 src/core/gdt.c          | 98 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/core/gdt.h          | 77 ++++++++++++++++++++++++++++++++++++++
 src/core/mem.c          |  8 ++++
 src/core/mem.h          | 11 ++++++
 src/core/paging.c       | 31 ++++++++++++++++
 src/core/paging.h       | 13 +++++++
 src/core/syscall.c      | 19 ++++++++++
 src/core/syscall.h      |  9 +++++
 src/core/types.h        |  9 +++++
 src/int/8042.c          |  4 +-
 src/int/8042.h          |  2 +-
 src/int/idt.c           | 39 +++++++++++++++++++
 src/int/idt.h           | 32 ++++++++++++++++
 src/int/int.S           | 72 +++++++++++++++++++++++++++++++++++
 src/int/pic.c           | 99 +++----------------------------------------------
 src/int/pic.h           | 22 ++---------
 src/libc/stdio.h        |  2 +-
 src/utils/asm.h         | 13 -------
 src/utils/framebuffer.c | 58 -----------------------------
 src/utils/framebuffer.h | 27 --------------
 src/utils/gdt.c         | 98 ------------------------------------------------
 src/utils/gdt.h         | 77 --------------------------------------
 src/utils/mem.c         |  8 ----
 src/utils/mem.h         |  8 ----
 src/utils/paging.c      | 31 ----------------
 src/utils/paging.h      | 10 -----
 src/utils/syscall.c     | 19 ----------
 src/utils/syscall.h     |  6 ---
 src/utils/types.h       |  9 -----
 36 files changed, 550 insertions(+), 491 deletions(-)
 create mode 100644 src/core/asm.h
 create mode 100644 src/core/framebuffer.c
 create mode 100644 src/core/framebuffer.h
 create mode 100644 src/core/gdt.c
 create mode 100644 src/core/gdt.h
 create mode 100644 src/core/mem.c
 create mode 100644 src/core/mem.h
 create mode 100644 src/core/paging.c
 create mode 100644 src/core/paging.h
 create mode 100644 src/core/syscall.c
 create mode 100644 src/core/syscall.h
 create mode 100644 src/core/types.h
 create mode 100644 src/int/idt.c
 create mode 100644 src/int/idt.h
 delete mode 100644 src/utils/asm.h
 delete mode 100644 src/utils/framebuffer.c
 delete mode 100644 src/utils/framebuffer.h
 delete mode 100644 src/utils/gdt.c
 delete mode 100644 src/utils/gdt.h
 delete mode 100644 src/utils/mem.c
 delete mode 100644 src/utils/mem.h
 delete mode 100644 src/utils/paging.c
 delete mode 100644 src/utils/paging.h
 delete mode 100644 src/utils/syscall.c
 delete mode 100644 src/utils/syscall.h
 delete mode 100644 src/utils/types.h

diff --git a/src/Makefile b/src/Makefile
index 2151883..3643f77 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -6,14 +6,14 @@ LD_SCRIPT := linker.ld
 # Indeed boot.o generated by boot.S should appear
 # first in the kernel binary (thus it must be linked first, cf the $(EXEC) rule)
 BOOT_OBJ := $(addsuffix .o,$(basename $(shell find ./boot -name "*.[c|S]" ! -name "boot.S")))
-UTILS_OBJ := $(addsuffix .o,$(basename $(shell find ./utils -name "*.[c|S]")))
+CORE_OBJ := $(addsuffix .o,$(basename $(shell find ./core -name "*.[c|S]")))
 LIBC_OBJ := $(addsuffix .o,$(basename $(shell find ./libc -name "*.[c|S]")))
 INT_OBJ := $(addsuffix .o,$(basename $(shell find ./int -name "*.[c|S]")))
 
 
 all: $(EXEC)
 
-$(EXEC): boot/boot.o $(BOOT_OBJ) $(UTILS_OBJ) $(LIBC_OBJ) $(INT_OBJ) bringelle.o
+$(EXEC): boot/boot.o $(BOOT_OBJ) $(CORE_OBJ) $(LIBC_OBJ) $(INT_OBJ) bringelle.o
 	ld -n -T $(LD_SCRIPT) -nostdlib -o bringelle $^ 
 
 %.o: %.S
diff --git a/src/boot/multiboot.c b/src/boot/multiboot.c
index c41aeb7..71382d5 100644
--- a/src/boot/multiboot.c
+++ b/src/boot/multiboot.c
@@ -1,5 +1,4 @@
 #include "multiboot.h"
-#include "utils/mem.h"
 
 /// See boot.S
 extern u8* MB_INFO;
diff --git a/src/boot/multiboot.h b/src/boot/multiboot.h
index 010f60b..9eae31f 100644
--- a/src/boot/multiboot.h
+++ b/src/boot/multiboot.h
@@ -1,7 +1,8 @@
 #ifndef MULTIBOOT_H
 #define MULTIBOOT_H
 
-#include "utils/types.h"
+#include "core/types.h"
+#include "core/mem.h"
 
 typedef struct MBI_TAG_HEADER {
     u32 type;
@@ -29,10 +30,12 @@ typedef struct MBI_TAG_FB {
  * Parse Bootloader boot information structure
  */
 char mb_load_tag(char **data, char type);
+
 /**
  * Search for Bootloader name
  */
 char mb_load_bl_name(MBI_TAG_BL_NAME *data);
+
 /**
  * Search for FrameBuffer structure (TODO: Finish)
  */
diff --git a/src/bringelle.c b/src/bringelle.c
index 340e884..49670e8 100644
--- a/src/bringelle.c
+++ b/src/bringelle.c
@@ -1,14 +1,14 @@
 #include "libc/stdio.h"
 #include "int/pic.h"
 #include "boot/multiboot.h"
-#include "utils/mem.h"
-#include "utils/gdt.h"
-#include "utils/paging.h"
-
+#include "core/mem.h"
+#include "core/gdt.h"
+#include "core/paging.h"
 
 char show_tics=0;
 
 extern GDT_TSS TSS;
+extern void interrupt_enable();
 
 void utask(){
   char msg[]="Message from the task :D";
@@ -20,8 +20,8 @@ void bringelle(){
   clear();
   printc("Booting Bringelle...\n",GREEN);
 
-  // Kernel boot sequence
-  pic_enable_interrupt();
+  // ----- Kernel boot sequence
+  interrupt_enable();
   print("Interrupts enabled\n");
 
   paging_enable();
@@ -52,8 +52,6 @@ void bringelle(){
     : "=m" (TSS.ss0), "=m" (TSS.esp0)
   );
 
-
-
   while(1);
 }
 
diff --git a/src/core/asm.h b/src/core/asm.h
new file mode 100644
index 0000000..be265d8
--- /dev/null
+++ b/src/core/asm.h
@@ -0,0 +1,13 @@
+#ifndef ASM_H
+#define ASM_H
+
+#define outb(port,value) \
+    asm volatile ("outb %%al, %%dx" :: "a"(value), "d" (port) )
+
+#define outbj(port,value) \
+    asm volatile ("outb %%al, %%dx;" :: "a" (value), "d"(port) )
+
+#define inb(port,dst) \
+    asm volatile ("inb %%dx, %%al": "=a" (dst) : "d" (port))
+
+#endif
\ No newline at end of file
diff --git a/src/core/framebuffer.c b/src/core/framebuffer.c
new file mode 100644
index 0000000..110dc73
--- /dev/null
+++ b/src/core/framebuffer.c
@@ -0,0 +1,58 @@
+#include "framebuffer.h"
+
+#define MAX_COL 80
+#define MAX_LINE 25
+
+VIDEO_STATE VS={
+  (u8 *)0xB8000,
+  0,
+  0,
+  BLACK,
+  GRAY,
+};
+
+void putchar(char c){
+  // Handle newline here
+  if(c=='\n'){
+    VS.col=0;
+    VS.line+=1;
+    if(VS.line>=MAX_LINE){
+      VS.line=MAX_LINE-1;
+      scrollup();
+    }
+    return;
+  }
+  
+  // Print char
+  VS.mem[VS.col*2+MAX_COL*VS.line*2]=c;
+  VS.mem[VS.col*2+MAX_COL*VS.line*2+1]=VS.fg|VS.bg<<4;
+  
+  // Refresh location
+  VS.col+=1;
+  if(VS.col>= MAX_COL){
+    VS.col=0;
+    VS.line+=1;
+    if(VS.line>=MAX_LINE){
+      VS.line=MAX_LINE-1;
+      scrollup();
+    }
+  }
+}
+
+void clear(){
+  for(char i=0;i<MAX_LINE;i++){
+    scrollup();
+  }
+}
+
+void scrollup(){
+  // Move VS.line up
+  for(char i=1;i<=MAX_LINE;i++){
+    for(char j=0;j<=MAX_COL;j++)
+      VS.mem[j*2+MAX_COL*(i-1)*2]=VS.mem[j*2+MAX_COL*i*2];
+  }
+  // Clear last VS.line
+  for(char i=0;i<=MAX_COL;i++){
+    VS.mem[i*2+MAX_COL*(MAX_LINE-1)*2]='\0';
+  }
+}
diff --git a/src/core/framebuffer.h b/src/core/framebuffer.h
new file mode 100644
index 0000000..3d862d6
--- /dev/null
+++ b/src/core/framebuffer.h
@@ -0,0 +1,35 @@
+#ifndef FRAMEBUFFER_H
+#define FRAMEBUFFER_H
+
+#include "types.h"
+
+typedef enum VIDEO_COLORS {
+  BLACK=0, BLUE=1, GREEN=2,CYAN=3, RED=4,PURPLE=5,BROWN=6,GRAY=7,
+  DARK_GRAY=8,LIGHT_BLUE=9,LIGHT_GREEN=10,LIGHT_CYAN=11,LIGHT_RED=12,LIGHT_PURPLE=13,YELLOW=14,WHITE=15
+  
+} VIDEO_COLORS;
+
+typedef struct VIDEO_STATE {
+  u8 *mem;
+  u8 col;
+  u8 line;
+  u8 bg;
+  u8 fg;
+} VIDEO_STATE;
+
+/**
+ * Print char
+ */
+void putchar(char);
+
+/**
+ * Scroll the framebuffer from one line
+ */
+void scrollup();
+
+/**
+ * Clear all char from the framebuffer
+ */
+void clear();
+
+#endif
diff --git a/src/core/gdt.c b/src/core/gdt.c
new file mode 100644
index 0000000..8c1c70d
--- /dev/null
+++ b/src/core/gdt.c
@@ -0,0 +1,98 @@
+#include "gdt.h"
+#include "mem.h"
+
+struct GDT_REGISTER GDTR = { 0, 0 };
+GDT_TSS TSS;
+
+void gdt_memcpy(){
+  GDTR.limit=8*GDT_MAX_ENTRIES; // Each entry is 8 bytes and 8 entries
+  GDTR.base=0x800;
+  gdt_write_entry((GDT_ENTRY){0,0,0,0},0); // First one must be null
+
+  // ----- Kernel Segments
+  GDT_ENTRY cs_desc;
+  cs_desc.base=0;
+  cs_desc.limit=0xFFFFF;
+  cs_desc.flags=GDT_SZ|GDT_GR;
+  cs_desc.access=GDT_PR|GDT_PRVL_0|GDT_S|GDT_EXEC|GDT_RW;
+  
+  GDT_ENTRY ds_desc;
+  ds_desc.base=0;
+  ds_desc.limit=0xFFFFF;
+  ds_desc.flags=GDT_SZ|GDT_GR;
+  ds_desc.access=GDT_PR|GDT_PRVL_0|GDT_S|GDT_RW;
+  
+  GDT_ENTRY ss_desc;
+  ss_desc.base=0;
+  ss_desc.limit=0;
+  ss_desc.flags=GDT_SZ|GDT_GR;
+  ss_desc.access=GDT_PR|GDT_PRVL_0|GDT_S|GDT_RW|GDT_DC;
+  
+  // Write GDT descriptors into memory
+  gdt_write_entry(cs_desc, 1);
+  gdt_write_entry(ds_desc, 2);
+  gdt_write_entry(ss_desc, 3);
+
+  // ----- User Segments
+  GDT_ENTRY ucs_desc;
+  ucs_desc.base=0; // With paging will take care of allocating the right address for each task
+  ucs_desc.limit=0xFFFFF;
+  ucs_desc.flags=GDT_SZ|GDT_GR;
+  ucs_desc.access=GDT_PR|GDT_PRVL_3|GDT_S|GDT_EXEC|GDT_RW|GDT_DC;
+  
+  GDT_ENTRY uds_desc;
+  uds_desc.base=0;
+  uds_desc.limit=0xFFFFF;
+  uds_desc.flags=GDT_SZ|GDT_GR;
+  uds_desc.access=GDT_PR|GDT_PRVL_3|GDT_S|GDT_RW;
+  
+  GDT_ENTRY uss_desc;
+  uss_desc.base=0; // Not used in stack descriptor
+  uss_desc.limit=0x64;  // Define how much entry it can contains
+  uss_desc.flags=GDT_SZ|GDT_GR;
+  uss_desc.access=GDT_PR|GDT_PRVL_3|GDT_S|GDT_RW|GDT_DC;
+  
+  // Write GDT descriptors into memory
+  gdt_write_entry(ucs_desc, 4); // Each entry is 64 bits (8 bytes)
+  gdt_write_entry(uds_desc, 5);
+  gdt_write_entry(uss_desc, 6);
+
+  // Init TSS segment
+  TSS.t_reserved=0;
+  TSS.io_map=0;
+
+  GDT_ENTRY tss_desc;
+  tss_desc.base=(u32)&TSS; // Not used in stack descriptor
+  tss_desc.limit=0x68;  // Define how much bytes it occupies
+  tss_desc.flags=0;
+  tss_desc.access=0x89 | GDT_PRVL_3; // Note that 0x89 is specific to TSS!
+  gdt_write_entry(tss_desc, 7);
+
+}
+
+void gdt_write_entry(GDT_ENTRY entry, u32 id){
+  int descriptor[2];
+
+  // First row of the descriptor
+  descriptor[0]=(entry.limit & 0xFFFF)|(entry.base << 16);
+
+  // Format second row of the descriptor
+  u16 base=(entry.base >> 16) & 0xFF;
+  u16 access=entry.access & 0xFF;
+  u16 limit=(entry.limit >> 16) & 0xF; // Remember: limits it is on 20 bits so 4 last bits
+  u8 flags=entry.flags & 0xF;
+  u8 base2=entry.base >> 24; // Take the last 8 bits
+  descriptor[1]=base|access<<8|limit<<16|flags<<20|base2<<24;
+
+  // Copy descriptor into memory
+  memcpy(descriptor,(void*)GDTR.base+8*id,8); // Each entry is 64 bits (8 bytes)
+}
+
+int gdt_user_ds_base(){
+  char *addr=(char*)GDTR.base+48;
+  int *base0_15=(int*)addr+2;
+  int *base16_31=(int*)addr+7;
+  int base0_15_content=*base0_15 & 0xFFFF;
+  int base16_21_content=*base16_31 & 0xFFFF;
+  return(base16_21_content<<16 & base0_15_content);
+}
\ No newline at end of file
diff --git a/src/core/gdt.h b/src/core/gdt.h
new file mode 100644
index 0000000..f010891
--- /dev/null
+++ b/src/core/gdt.h
@@ -0,0 +1,77 @@
+#ifndef GDT_H
+#define GDT_H
+
+#include "types.h"
+
+#define GDT_MAX_ENTRIES 8
+
+// Access byte
+#define GDT_AC 1            // Access bit
+#define GDT_RW 1 << 1       // Read/Write bit
+#define GDT_DC 1 << 2       // Direction bit/Conforming bit
+#define GDT_EXEC 1 << 3     // Executable bit
+#define GDT_S 1 << 4        // Descriptor type
+#define GDT_PRVL_0 0        // Privilege (from 0 to 3)
+#define GDT_PRVL_1 1 << 5
+#define GDT_PRVL_2 2 << 5
+#define GDT_PRVL_3 3 << 5
+#define GDT_PR 1 << 7       // Present Bit
+
+// Flags
+#define GDT_SZ 1 << 2       // Size bit
+#define GDT_GR 1 << 3       // Granularity bit
+
+typedef struct GDT_ENTRY {
+  u32 base;
+  u32 limit;
+  u8 flags;
+  u8 access;
+} GDT_ENTRY;
+
+struct GDT_REGISTER {
+  u16 limit;
+  u32 base;
+} __attribute__((packed));
+
+typedef struct GDT_TSS {
+  u16 previous_task,previous_task_unused;
+  u32 esp0;
+  u16 ss0, ss0_unused;
+  u32 esp1;
+  u16 ss1, ss1_unused;
+  u32 esp2;
+  u16 ss2, ss2_unused;
+  u32 cr3;
+  u32 eip;
+  u32 eflags;
+  u32 eax;
+  u32 ecx;
+  u32 edx;
+  u32 ebx;
+  u32 esp;
+  u32 ebp;
+  u32 esi;
+  u32 edi;
+  u16 es, es_reserved;
+  u16 cs, cs_reserved;
+  u16 ss, ss_reserved;
+  u16 ds, ds_reserved;
+  u16 fs, fs_reserved;
+  u16 gs, gs_reserved;
+  u16 ldtss, ldtss_reserved;
+  u16 t_reserved, io_map;
+} __attribute__((packed)) GDT_TSS;
+
+/**
+ * Copy GDT in memory
+ */
+void gdt_memcpy();
+
+/**
+ * Write a GDT entry at address addr
+ */
+void gdt_write_entry(GDT_ENTRY entry, u32 id);
+
+int gdt_user_ds_base();
+
+#endif
diff --git a/src/core/mem.c b/src/core/mem.c
new file mode 100644
index 0000000..4cefd6d
--- /dev/null
+++ b/src/core/mem.c
@@ -0,0 +1,8 @@
+#include "mem.h"
+
+void memcpy(void *src, void *dst, int size){
+  u8 *char_src=(u8 *)src;
+  u8 *char_dst=(u8 *)dst;
+  for(int i=0;i<size;i++)
+    char_dst[i]=char_src[i];
+}
diff --git a/src/core/mem.h b/src/core/mem.h
new file mode 100644
index 0000000..5bef441
--- /dev/null
+++ b/src/core/mem.h
@@ -0,0 +1,11 @@
+#ifndef MEM_H
+#define MEM_H
+
+#include "types.h"
+
+/**
+ * Copy size byte from *src to *dst
+ */
+void memcpy(void *src, void *dst, int size);
+
+#endif
diff --git a/src/core/paging.c b/src/core/paging.c
new file mode 100644
index 0000000..b1f462f
--- /dev/null
+++ b/src/core/paging.c
@@ -0,0 +1,31 @@
+#include "paging.h"
+
+void paging_enable(){
+    int *page_dir=(int*)PAGING_DIR_LOCATION;
+    int *page_table=(int*)PAGING_TABLE_LOCATION;
+
+    // Init page directory
+    for(int i=0;i<1024;i++)
+        page_dir[i]=0;
+    page_dir[0]=(int)page_table;
+    page_dir[0] |=7; // Permissions
+
+    // Init page table 0
+    int addr_offset=0;
+    for(int i=0;i<1024;i++){
+        page_table[i]=addr_offset;
+        page_table[i]|=7; // Permission
+        addr_offset+=4096; // 4Ko pages
+    }
+
+    // Turns on paging
+    asm(
+        "movl %0, %%eax       \n\t"
+        "movl %%eax, %%cr3    \n\t" // Configure page table location
+        "movl %%cr0, %%eax    \n\t"
+        "orl %1, %%eax        \n\t"
+        "movl %%eax, %%cr0    \n\t" // Turn on paging
+        :: "i" (PAGING_DIR_LOCATION), "i" (PAGING_CR0_BIT)
+    );
+
+}
\ No newline at end of file
diff --git a/src/core/paging.h b/src/core/paging.h
new file mode 100644
index 0000000..1e8f4e3
--- /dev/null
+++ b/src/core/paging.h
@@ -0,0 +1,13 @@
+#ifndef PAGING_H
+#define PAGING_H
+
+#define PAGING_CR0_BIT 0x80000000
+#define PAGING_DIR_LOCATION 0x1000
+#define PAGING_TABLE_LOCATION 0x5000
+
+/*
+ * Configure and enable paging
+ */
+void paging_enable();
+
+#endif
\ No newline at end of file
diff --git a/src/core/syscall.c b/src/core/syscall.c
new file mode 100644
index 0000000..300b7aa
--- /dev/null
+++ b/src/core/syscall.c
@@ -0,0 +1,19 @@
+#include "syscall.h"
+#include "gdt.h"
+#include "libc/stdio.h"
+
+void syscall(){
+    int call_number;
+    asm("movl %%eax, %0":"=m"(call_number));
+    if(call_number==1){
+        int msg_addr;
+        asm("movl %%ebx, %0":"=m"(msg_addr));
+        char *msg=(char*)msg_addr;
+        print(msg);
+    }
+    else{
+        print("Syscall ");
+        printi(call_number);
+        print(" unknown");
+    }
+}
\ No newline at end of file
diff --git a/src/core/syscall.h b/src/core/syscall.h
new file mode 100644
index 0000000..1f0c584
--- /dev/null
+++ b/src/core/syscall.h
@@ -0,0 +1,9 @@
+#ifndef SYSCALL_H
+#define SYSCALL_H
+
+/*
+ * Perform a syscall
+ */
+void syscall();
+
+#endif
\ No newline at end of file
diff --git a/src/core/types.h b/src/core/types.h
new file mode 100644
index 0000000..071d8d6
--- /dev/null
+++ b/src/core/types.h
@@ -0,0 +1,9 @@
+#ifndef TYPES_H
+#define TYPES_H
+
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+typedef unsigned long long u64;
+
+#endif
diff --git a/src/int/8042.c b/src/int/8042.c
index f0a987f..5446f11 100644
--- a/src/int/8042.c
+++ b/src/int/8042.c
@@ -1,6 +1,6 @@
 #include "8042.h"
-#include "utils/framebuffer.h"
-#include "utils/asm.h"
+#include "core/framebuffer.h"
+#include "core/asm.h"
 
 DEFINE_AZERTY;
 
diff --git a/src/int/8042.h b/src/int/8042.h
index e35e5a0..5e61ffd 100644
--- a/src/int/8042.h
+++ b/src/int/8042.h
@@ -1,7 +1,7 @@
 #ifndef _8042_H
 #define _8042_H
 
-#include "utils/types.h"
+#include "core/types.h"
 
 void _8042_keypress();
 
diff --git a/src/int/idt.c b/src/int/idt.c
new file mode 100644
index 0000000..e3e71e8
--- /dev/null
+++ b/src/int/idt.c
@@ -0,0 +1,39 @@
+#include "idt.h"
+
+struct IDT_REGISTER IDTR={
+    8*IDT_MAX_ENTRY,
+    0x0
+};
+
+// Interrupt functions (cf int.S)
+extern u32
+INT_DEFAULT,
+INT_PAGE_FAULT,
+INT_CLOCK,
+INT_KEYPRESS,
+INT_SYSCALL;
+
+
+void idt_init(){
+        // Map first default 32 entries 
+    for(int i=0;i<IDT_MAX_ENTRY;i++){
+        idt_write_entry((IDT_ENTRY){0x08,(u32)&INT_DEFAULT,IDT_INT_GATE},i);
+        if(i==14)
+            idt_write_entry((IDT_ENTRY){0x08,(u32)&INT_PAGE_FAULT,IDT_INT_GATE},i);
+        if(i==32)
+            idt_write_entry((IDT_ENTRY){0x08,(u32)&INT_CLOCK,IDT_INT_GATE},i);
+        if(i==33)
+            idt_write_entry((IDT_ENTRY){0x08,(u32)&INT_KEYPRESS,IDT_INT_GATE},i);
+        if(i==48)
+            idt_write_entry((IDT_ENTRY){0x08,(u32)&INT_SYSCALL,IDT_TRAP_GATE},i);
+    }
+    
+    asm("lidtl (IDTR)");
+}
+
+void idt_write_entry(IDT_ENTRY entry, int id){
+    int descriptor[2];
+    descriptor[0]=entry.offset & 0xFFFF | entry.segment << 16;
+    descriptor[1]=entry.type & 0xFFFF | entry.offset & 0xFFFF0000;
+    memcpy((void*)descriptor, (void *)(IDTR.base+(id*8)),8);
+}
\ No newline at end of file
diff --git a/src/int/idt.h b/src/int/idt.h
new file mode 100644
index 0000000..17c5cfa
--- /dev/null
+++ b/src/int/idt.h
@@ -0,0 +1,32 @@
+#ifndef IDT_H
+#define IDT_H
+
+#include "core/types.h"
+#include "core/mem.h"
+
+#define IDT_MAX_ENTRY 200
+#define IDT_INT_GATE 0x8E00
+#define IDT_TRAP_GATE 0xEF00
+
+typedef struct IDT_ENTRY {
+    u16 segment;
+    u32 offset;
+    u16 type;
+} IDT_ENTRY;
+
+struct IDT_REGISTER {
+    u16 limit;
+    u32 base;
+} __attribute__((packed));
+
+/**
+ * Copy IDT into memory and load it
+ */
+void idt_init();
+
+/**
+ * Write an IDT entry into memory
+ */
+void idt_write_entry(IDT_ENTRY entry,int id);
+
+#endif
\ No newline at end of file
diff --git a/src/int/int.S b/src/int/int.S
index e69de29..8ca8b7a 100644
--- a/src/int/int.S
+++ b/src/int/int.S
@@ -0,0 +1,72 @@
+.macro  SAVE_REGS
+pushal             
+push %ds
+push %es
+push %fs
+push %gs
+push %ebx
+mov $0x10,%bx
+mov %bx,%ds
+pop %ebx
+.endm
+
+.macro RESTORE_REGS
+    pop %gs
+    pop %fs
+    pop %es
+    pop %ds
+    popal
+.endm
+
+.globl interrupt_enable
+interrupt_enable:
+    call idt_init
+    call pic_init
+    sti
+    ret
+
+.globl INT_DEFAULT
+INT_DEFAULT:
+    SAVE_REGS
+    movb $0x20, %al
+    outb %al, $0x20
+    RESTORE_REGS
+    iret
+
+.globl INT_KEYPRESS
+INT_KEYPRESS:
+    SAVE_REGS
+    call _8042_keypress
+    movb $0x20, %al
+    outb %al, $0x20
+    RESTORE_REGS
+    iret
+
+.globl INT_CLOCK
+INT_CLOCK:
+    SAVE_REGS
+    call clock
+    movb $0x20, %al
+    outb %al, $0x20
+    RESTORE_REGS
+    iret
+
+.globl INT_SYSCALL
+INT_SYSCALL:
+    SAVE_REGS
+    call syscall
+    movb $0x20, %al
+    outb %al, $0x20
+    RESTORE_REGS
+    iret
+
+.globl INT_PAGE_FAULT
+INT_PAGE_FAULT:
+    SAVE_REGS
+    call page_fault
+    hlt
+    movb $0x20, %al
+    outb %al, $0x20
+    RESTORE_REGS
+    iret
+
diff --git a/src/int/pic.c b/src/int/pic.c
index 472e50c..d509e1d 100644
--- a/src/int/pic.c
+++ b/src/int/pic.c
@@ -1,88 +1,10 @@
 #include "pic.h"
-#include "utils/asm.h"
-#include "utils/mem.h"
-#include "utils/syscall.h"
-
-struct IDT_REGISTER IDTR={
-    200*8,
-    0x0
-};
-
-/// Bridge between IDT and functions call
-asm (
-".macro  SAVE_REGS        \n\t"
-    "pushal               \n\t"
-    "push %ds             \n\t"
-    "push %es             \n\t"
-    "push %fs             \n\t"
-    "push %gs             \n\t"
-    "push %ebx            \n\t"
-    "mov $0x10,%bx        \n\t"
-    "mov %bx,%ds          \n\t"
-    "pop %ebx             \n\t"
-".endm                    \n\t"
-".macro  RESTORE_REGS     \n\t"
-    "pop %gs              \n\t"
-    "pop %fs              \n\t"
-    "pop %es              \n\t"
-    "pop %ds              \n\t"
-    "popal                \n\t"
-".endm                    \n\t"
-"PIC_IRQ_DEFAULT:         \n\t"
-    "SAVE_REGS            \n\t"
-    "movb $0x20, %al      \n\t"
-    "outb %al, $0x20      \n\t"
-    "RESTORE_REGS         \n\t"
-    "iret                 \n\t"
-"PIC_IRQ_PRINT:           \n\t"
-    "SAVE_REGS            \n\t"
-    "call _8042_keypress  \n\t"
-    "movb $0x20, %al      \n\t"
-    "outb %al, $0x20      \n\t"
-    "RESTORE_REGS         \n\t"
-    "iret                 \n\t"
-"PIC_IRQ_CLOCK:           \n\t"
-    "SAVE_REGS            \n\t"
-    "call clock           \n\t"
-    "movb $0x20, %al      \n\t"
-    "outb %al, $0x20      \n\t"
-    "RESTORE_REGS         \n\t"
-    "iret                 \n\t"
-"PIC_IRQ_SYSCALL:         \n\t"
-    "SAVE_REGS            \n\t"
-    "call syscall         \n\t"
-    "movb $0x20, %al      \n\t"
-    "outb %al, $0x20      \n\t"
-    "RESTORE_REGS         \n\t"
-    "iret                 \n\t"
-"INT_PAGE_FAULT:          \n\t"
-    "SAVE_REGS            \n\t"
-    "call page_fault      \n\t"
-    "hlt                  \n\t"
-    "movb $0x20, %al      \n\t"
-    "outb %al, $0x20      \n\t"
-    "RESTORE_REGS         \n\t"
-    "iret                 \n\t"
-);
-
-extern u32 PIC_IRQ_DEFAULT,PIC_IRQ_PRINT,PIC_IRQ_CLOCK, PIC_IRQ_SYSCALL,INT_PAGE_FAULT;
-
-void pic_enable_interrupt(){
-    // Map first default 32 entries 
-    for(int i=0;i<200;i++){
-        pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_DEFAULT,IDT_INT_GATE},i);
-        if(i==14)
-            pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&INT_PAGE_FAULT,IDT_INT_GATE},i);
-        if(i==32)
-            pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_CLOCK,IDT_INT_GATE},i);
-        if(i==33)
-            pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_PRINT,IDT_INT_GATE},i);
-        if(i==48)
-            pic_add_idt_entry((IDT_ENTRY){0x08,(u32)&PIC_IRQ_SYSCALL,IDT_TRAP_GATE},i);
-    }
-
-    // Now configure 8952A
+#include "core/asm.h"
+#include "core/mem.h"
+#include "core/syscall.h"
 
+void pic_init(){
+    
     // ICW1: Initialisation
     outbj(0x20,0x11); // Master
     outbj(0xA0,0x11); // Slave
@@ -101,15 +23,6 @@ void pic_enable_interrupt(){
 
     // OCW: Masking
     outbj(0x21,0b11111100);
-
-
-    asm("lidtl (IDTR)");
-    asm("sti");
 }
 
-void pic_add_idt_entry(IDT_ENTRY entry, int id){
-    int descriptor[2];
-    descriptor[0]=entry.offset & 0xFFFF | entry.segment << 16;
-    descriptor[1]=entry.type & 0xFFFF | entry.offset & 0xFFFF0000;
-    memcpy((void*)descriptor, (void *)(IDTR.base+(id*8)),8);
-}
+
diff --git a/src/int/pic.h b/src/int/pic.h
index db1ccec..19e0f5c 100644
--- a/src/int/pic.h
+++ b/src/int/pic.h
@@ -1,23 +1,9 @@
 #ifndef PIC_H
 #define PIC_H
 
-#include "utils/types.h"
-
-#define IDT_INT_GATE 0x8E00
-#define IDT_TRAP_GATE 0xEF00
-
-typedef struct IDT_ENTRY {
-    u16 segment;
-    u32 offset;
-    u16 type;
-} IDT_ENTRY;
-
-struct IDT_REGISTER {
-    u16 limit;
-    u32 base;
-} __attribute__((packed));
-
-void pic_enable_interrupt();
-void pic_add_idt_entry(IDT_ENTRY entry,int id);
+/**
+ * Configure 
+ */
+void pic_init();
 
 #endif
\ No newline at end of file
diff --git a/src/libc/stdio.h b/src/libc/stdio.h
index ece8df5..5805f5a 100644
--- a/src/libc/stdio.h
+++ b/src/libc/stdio.h
@@ -1,7 +1,7 @@
 #ifndef STDIO_H
 #define STDIO_H
 
-#include "utils/framebuffer.h"
+#include "core/framebuffer.h"
 
 void print(char*);
 void printc(char*,VIDEO_COLORS c);
diff --git a/src/utils/asm.h b/src/utils/asm.h
deleted file mode 100644
index be265d8..0000000
--- a/src/utils/asm.h
+++ /dev/null
@@ -1,13 +0,0 @@
-#ifndef ASM_H
-#define ASM_H
-
-#define outb(port,value) \
-    asm volatile ("outb %%al, %%dx" :: "a"(value), "d" (port) )
-
-#define outbj(port,value) \
-    asm volatile ("outb %%al, %%dx;" :: "a" (value), "d"(port) )
-
-#define inb(port,dst) \
-    asm volatile ("inb %%dx, %%al": "=a" (dst) : "d" (port))
-
-#endif
\ No newline at end of file
diff --git a/src/utils/framebuffer.c b/src/utils/framebuffer.c
deleted file mode 100644
index 110dc73..0000000
--- a/src/utils/framebuffer.c
+++ /dev/null
@@ -1,58 +0,0 @@
-#include "framebuffer.h"
-
-#define MAX_COL 80
-#define MAX_LINE 25
-
-VIDEO_STATE VS={
-  (u8 *)0xB8000,
-  0,
-  0,
-  BLACK,
-  GRAY,
-};
-
-void putchar(char c){
-  // Handle newline here
-  if(c=='\n'){
-    VS.col=0;
-    VS.line+=1;
-    if(VS.line>=MAX_LINE){
-      VS.line=MAX_LINE-1;
-      scrollup();
-    }
-    return;
-  }
-  
-  // Print char
-  VS.mem[VS.col*2+MAX_COL*VS.line*2]=c;
-  VS.mem[VS.col*2+MAX_COL*VS.line*2+1]=VS.fg|VS.bg<<4;
-  
-  // Refresh location
-  VS.col+=1;
-  if(VS.col>= MAX_COL){
-    VS.col=0;
-    VS.line+=1;
-    if(VS.line>=MAX_LINE){
-      VS.line=MAX_LINE-1;
-      scrollup();
-    }
-  }
-}
-
-void clear(){
-  for(char i=0;i<MAX_LINE;i++){
-    scrollup();
-  }
-}
-
-void scrollup(){
-  // Move VS.line up
-  for(char i=1;i<=MAX_LINE;i++){
-    for(char j=0;j<=MAX_COL;j++)
-      VS.mem[j*2+MAX_COL*(i-1)*2]=VS.mem[j*2+MAX_COL*i*2];
-  }
-  // Clear last VS.line
-  for(char i=0;i<=MAX_COL;i++){
-    VS.mem[i*2+MAX_COL*(MAX_LINE-1)*2]='\0';
-  }
-}
diff --git a/src/utils/framebuffer.h b/src/utils/framebuffer.h
deleted file mode 100644
index f4e52a0..0000000
--- a/src/utils/framebuffer.h
+++ /dev/null
@@ -1,27 +0,0 @@
-#ifndef FRAMEBUFFER_H
-#define FRAMEBUFFER_H
-
-#include "types.h"
-
-typedef enum VIDEO_COLORS {
-  BLACK=0, BLUE=1, GREEN=2,CYAN=3, RED=4,PURPLE=5,BROWN=6,GRAY=7,
-  DARK_GRAY=8,LIGHT_BLUE=9,LIGHT_GREEN=10,LIGHT_CYAN=11,LIGHT_RED=12,LIGHT_PURPLE=13,YELLOW=14,WHITE=15
-  
-} VIDEO_COLORS;
-
-typedef struct VIDEO_STATE {
-  u8 *mem;
-  u8 col;
-  u8 line;
-  u8 bg;
-  u8 fg;
-} VIDEO_STATE;
-
-/**
- * Print char
- */
-void putchar(char);
-void scrollup();
-void clear();
-
-#endif
diff --git a/src/utils/gdt.c b/src/utils/gdt.c
deleted file mode 100644
index 8c1c70d..0000000
--- a/src/utils/gdt.c
+++ /dev/null
@@ -1,98 +0,0 @@
-#include "gdt.h"
-#include "mem.h"
-
-struct GDT_REGISTER GDTR = { 0, 0 };
-GDT_TSS TSS;
-
-void gdt_memcpy(){
-  GDTR.limit=8*GDT_MAX_ENTRIES; // Each entry is 8 bytes and 8 entries
-  GDTR.base=0x800;
-  gdt_write_entry((GDT_ENTRY){0,0,0,0},0); // First one must be null
-
-  // ----- Kernel Segments
-  GDT_ENTRY cs_desc;
-  cs_desc.base=0;
-  cs_desc.limit=0xFFFFF;
-  cs_desc.flags=GDT_SZ|GDT_GR;
-  cs_desc.access=GDT_PR|GDT_PRVL_0|GDT_S|GDT_EXEC|GDT_RW;
-  
-  GDT_ENTRY ds_desc;
-  ds_desc.base=0;
-  ds_desc.limit=0xFFFFF;
-  ds_desc.flags=GDT_SZ|GDT_GR;
-  ds_desc.access=GDT_PR|GDT_PRVL_0|GDT_S|GDT_RW;
-  
-  GDT_ENTRY ss_desc;
-  ss_desc.base=0;
-  ss_desc.limit=0;
-  ss_desc.flags=GDT_SZ|GDT_GR;
-  ss_desc.access=GDT_PR|GDT_PRVL_0|GDT_S|GDT_RW|GDT_DC;
-  
-  // Write GDT descriptors into memory
-  gdt_write_entry(cs_desc, 1);
-  gdt_write_entry(ds_desc, 2);
-  gdt_write_entry(ss_desc, 3);
-
-  // ----- User Segments
-  GDT_ENTRY ucs_desc;
-  ucs_desc.base=0; // With paging will take care of allocating the right address for each task
-  ucs_desc.limit=0xFFFFF;
-  ucs_desc.flags=GDT_SZ|GDT_GR;
-  ucs_desc.access=GDT_PR|GDT_PRVL_3|GDT_S|GDT_EXEC|GDT_RW|GDT_DC;
-  
-  GDT_ENTRY uds_desc;
-  uds_desc.base=0;
-  uds_desc.limit=0xFFFFF;
-  uds_desc.flags=GDT_SZ|GDT_GR;
-  uds_desc.access=GDT_PR|GDT_PRVL_3|GDT_S|GDT_RW;
-  
-  GDT_ENTRY uss_desc;
-  uss_desc.base=0; // Not used in stack descriptor
-  uss_desc.limit=0x64;  // Define how much entry it can contains
-  uss_desc.flags=GDT_SZ|GDT_GR;
-  uss_desc.access=GDT_PR|GDT_PRVL_3|GDT_S|GDT_RW|GDT_DC;
-  
-  // Write GDT descriptors into memory
-  gdt_write_entry(ucs_desc, 4); // Each entry is 64 bits (8 bytes)
-  gdt_write_entry(uds_desc, 5);
-  gdt_write_entry(uss_desc, 6);
-
-  // Init TSS segment
-  TSS.t_reserved=0;
-  TSS.io_map=0;
-
-  GDT_ENTRY tss_desc;
-  tss_desc.base=(u32)&TSS; // Not used in stack descriptor
-  tss_desc.limit=0x68;  // Define how much bytes it occupies
-  tss_desc.flags=0;
-  tss_desc.access=0x89 | GDT_PRVL_3; // Note that 0x89 is specific to TSS!
-  gdt_write_entry(tss_desc, 7);
-
-}
-
-void gdt_write_entry(GDT_ENTRY entry, u32 id){
-  int descriptor[2];
-
-  // First row of the descriptor
-  descriptor[0]=(entry.limit & 0xFFFF)|(entry.base << 16);
-
-  // Format second row of the descriptor
-  u16 base=(entry.base >> 16) & 0xFF;
-  u16 access=entry.access & 0xFF;
-  u16 limit=(entry.limit >> 16) & 0xF; // Remember: limits it is on 20 bits so 4 last bits
-  u8 flags=entry.flags & 0xF;
-  u8 base2=entry.base >> 24; // Take the last 8 bits
-  descriptor[1]=base|access<<8|limit<<16|flags<<20|base2<<24;
-
-  // Copy descriptor into memory
-  memcpy(descriptor,(void*)GDTR.base+8*id,8); // Each entry is 64 bits (8 bytes)
-}
-
-int gdt_user_ds_base(){
-  char *addr=(char*)GDTR.base+48;
-  int *base0_15=(int*)addr+2;
-  int *base16_31=(int*)addr+7;
-  int base0_15_content=*base0_15 & 0xFFFF;
-  int base16_21_content=*base16_31 & 0xFFFF;
-  return(base16_21_content<<16 & base0_15_content);
-}
\ No newline at end of file
diff --git a/src/utils/gdt.h b/src/utils/gdt.h
deleted file mode 100644
index f010891..0000000
--- a/src/utils/gdt.h
+++ /dev/null
@@ -1,77 +0,0 @@
-#ifndef GDT_H
-#define GDT_H
-
-#include "types.h"
-
-#define GDT_MAX_ENTRIES 8
-
-// Access byte
-#define GDT_AC 1            // Access bit
-#define GDT_RW 1 << 1       // Read/Write bit
-#define GDT_DC 1 << 2       // Direction bit/Conforming bit
-#define GDT_EXEC 1 << 3     // Executable bit
-#define GDT_S 1 << 4        // Descriptor type
-#define GDT_PRVL_0 0        // Privilege (from 0 to 3)
-#define GDT_PRVL_1 1 << 5
-#define GDT_PRVL_2 2 << 5
-#define GDT_PRVL_3 3 << 5
-#define GDT_PR 1 << 7       // Present Bit
-
-// Flags
-#define GDT_SZ 1 << 2       // Size bit
-#define GDT_GR 1 << 3       // Granularity bit
-
-typedef struct GDT_ENTRY {
-  u32 base;
-  u32 limit;
-  u8 flags;
-  u8 access;
-} GDT_ENTRY;
-
-struct GDT_REGISTER {
-  u16 limit;
-  u32 base;
-} __attribute__((packed));
-
-typedef struct GDT_TSS {
-  u16 previous_task,previous_task_unused;
-  u32 esp0;
-  u16 ss0, ss0_unused;
-  u32 esp1;
-  u16 ss1, ss1_unused;
-  u32 esp2;
-  u16 ss2, ss2_unused;
-  u32 cr3;
-  u32 eip;
-  u32 eflags;
-  u32 eax;
-  u32 ecx;
-  u32 edx;
-  u32 ebx;
-  u32 esp;
-  u32 ebp;
-  u32 esi;
-  u32 edi;
-  u16 es, es_reserved;
-  u16 cs, cs_reserved;
-  u16 ss, ss_reserved;
-  u16 ds, ds_reserved;
-  u16 fs, fs_reserved;
-  u16 gs, gs_reserved;
-  u16 ldtss, ldtss_reserved;
-  u16 t_reserved, io_map;
-} __attribute__((packed)) GDT_TSS;
-
-/**
- * Copy GDT in memory
- */
-void gdt_memcpy();
-
-/**
- * Write a GDT entry at address addr
- */
-void gdt_write_entry(GDT_ENTRY entry, u32 id);
-
-int gdt_user_ds_base();
-
-#endif
diff --git a/src/utils/mem.c b/src/utils/mem.c
deleted file mode 100644
index 4cefd6d..0000000
--- a/src/utils/mem.c
+++ /dev/null
@@ -1,8 +0,0 @@
-#include "mem.h"
-
-void memcpy(void *src, void *dst, int size){
-  u8 *char_src=(u8 *)src;
-  u8 *char_dst=(u8 *)dst;
-  for(int i=0;i<size;i++)
-    char_dst[i]=char_src[i];
-}
diff --git a/src/utils/mem.h b/src/utils/mem.h
deleted file mode 100644
index f051219..0000000
--- a/src/utils/mem.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#ifndef MEM_H
-#define MEM_H
-
-#include "types.h"
-
-void memcpy(void *src, void *dst, int size);
-
-#endif
diff --git a/src/utils/paging.c b/src/utils/paging.c
deleted file mode 100644
index b1f462f..0000000
--- a/src/utils/paging.c
+++ /dev/null
@@ -1,31 +0,0 @@
-#include "paging.h"
-
-void paging_enable(){
-    int *page_dir=(int*)PAGING_DIR_LOCATION;
-    int *page_table=(int*)PAGING_TABLE_LOCATION;
-
-    // Init page directory
-    for(int i=0;i<1024;i++)
-        page_dir[i]=0;
-    page_dir[0]=(int)page_table;
-    page_dir[0] |=7; // Permissions
-
-    // Init page table 0
-    int addr_offset=0;
-    for(int i=0;i<1024;i++){
-        page_table[i]=addr_offset;
-        page_table[i]|=7; // Permission
-        addr_offset+=4096; // 4Ko pages
-    }
-
-    // Turns on paging
-    asm(
-        "movl %0, %%eax       \n\t"
-        "movl %%eax, %%cr3    \n\t" // Configure page table location
-        "movl %%cr0, %%eax    \n\t"
-        "orl %1, %%eax        \n\t"
-        "movl %%eax, %%cr0    \n\t" // Turn on paging
-        :: "i" (PAGING_DIR_LOCATION), "i" (PAGING_CR0_BIT)
-    );
-
-}
\ No newline at end of file
diff --git a/src/utils/paging.h b/src/utils/paging.h
deleted file mode 100644
index 3e6b3f8..0000000
--- a/src/utils/paging.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#ifndef PAGING_H
-#define PAGING_H
-
-#define PAGING_CR0_BIT 0x80000000
-#define PAGING_DIR_LOCATION 0x1000
-#define PAGING_TABLE_LOCATION 0x5000
-
-void paging_enable();
-
-#endif
\ No newline at end of file
diff --git a/src/utils/syscall.c b/src/utils/syscall.c
deleted file mode 100644
index 300b7aa..0000000
--- a/src/utils/syscall.c
+++ /dev/null
@@ -1,19 +0,0 @@
-#include "syscall.h"
-#include "gdt.h"
-#include "libc/stdio.h"
-
-void syscall(){
-    int call_number;
-    asm("movl %%eax, %0":"=m"(call_number));
-    if(call_number==1){
-        int msg_addr;
-        asm("movl %%ebx, %0":"=m"(msg_addr));
-        char *msg=(char*)msg_addr;
-        print(msg);
-    }
-    else{
-        print("Syscall ");
-        printi(call_number);
-        print(" unknown");
-    }
-}
\ No newline at end of file
diff --git a/src/utils/syscall.h b/src/utils/syscall.h
deleted file mode 100644
index 26f3682..0000000
--- a/src/utils/syscall.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef SYSCALL_H
-#define SYSCALL_H
-
-void syscall();
-
-#endif
\ No newline at end of file
diff --git a/src/utils/types.h b/src/utils/types.h
deleted file mode 100644
index ce49701..0000000
--- a/src/utils/types.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#ifndef TYPES_H
-#define TYPES_h
-
-typedef unsigned char u8;
-typedef unsigned short u16;
-typedef unsigned int u32;
-typedef unsigned long long u64;
-
-#endif
-- 
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