diff --git a/Makefile b/Makefile
index 5635782..d0bec82 100644
--- a/Makefile
+++ b/Makefile
@@ -84,6 +84,14 @@ make_disk:
@echo ${CL2}[make_disk]${CL} OK${CL3}
testloader: loader
+ @qemu-system-x86_64 -hda build/bin/disk.img -d cpu_reset,guest_errors,pcall,int -enable-kvm 2> qemu.log &
+ @ndisasm $(OBJDIR)/boot/loader.bin -b 32 > loader_dism.asm
+
+testloader32: loader
+ @qemu-system-i386 -hda build/bin/disk.img -d cpu_reset,guest_errors,pcall,int -enable-kvm 2> qemu.log &
+ @ndisasm $(OBJDIR)/boot/loader.bin -b 32 > loader_dism.asm
+
+debugloader: loader
@qemu-system-x86_64 -hda build/bin/disk.img -d cpu_reset,guest_errors,pcall,int -s -S -enable-kvm 2> qemu.log &
@ndisasm $(OBJDIR)/boot/loader.bin -b 32 > loader_dism.asm
diff --git a/boot/loader/cpu/cpu.asm b/boot/loader/cpu/cpu.asm
deleted file mode 100644
index b875758..0000000
--- a/boot/loader/cpu/cpu.asm
+++ /dev/null
@@ -1,46 +0,0 @@
-;=----------------------------------------------------------------------------=;
-; GNU GPL OS/K ;
-; ;
-; Desc: Basic longmode CPU functions ;
-; (x86_64 architecture only) ;
-; ;
-; ;
-; Copyright © 2018-2019 The OS/K Team ;
-; ;
-; This file is part of OS/K. ;
-; ;
-; OS/K is free software: you can redistribute it and/or modify ;
-; it under the terms of the GNU General Public License as published by ;
-; the Free Software Foundation, either version 3 of the License, or ;
-; (at your option) any later version. ;
-; ;
-; OS/K is distributed in the hope that it will be useful, ;
-; but WITHOUT ANY WARRANTY; without even the implied warranty of ;
-; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;
-; GNU General Public License for more details. ;
-; ;
-; You should have received a copy of the GNU General Public License ;
-; along with OS/K. If not, see . ;
-;=----------------------------------------------------------------------------=;
-
-[BITS 64]
-
-temporize:
- push rcx
- mov rcx, 2000
-.looping:
- nop
- nop
- nop
- loop .looping
- pop rcx
- ret
-
-bitemporize:
- push rcx
- mov rcx, 2000
-.looping:
- call temporize
- loop .looping
- pop rcx
- ret
diff --git a/boot/loader/cpu/cpuid.inc b/boot/loader/cpu/cpuid.inc
index 44e19e7..7dabd42 100644
--- a/boot/loader/cpu/cpuid.inc
+++ b/boot/loader/cpu/cpuid.inc
@@ -44,7 +44,7 @@ Is64Bits:
jz .no_64 ; If it's not set, there is no long mode
ret
.no_64:
- mov al, "2" ; ERROR 1 : 64bits unsupported
+ mov ax, "01" ; ERROR 01 : 64bits unsupported
jmp Error
; ---------------------------------------------------------------------------- ;
@@ -66,5 +66,5 @@ Check_cpuid:
je .no_cpuid
ret
.no_cpuid:
- mov al, "1" ; ERROR 1 : CPUID UNSUPPORTED
+ mov ax, "02" ; ERROR 02 : CPUID UNSUPPORTED
jmp Error
diff --git a/boot/loader/io/ata.asm b/boot/loader/io/ata.asm
deleted file mode 100644
index c37cfc6..0000000
--- a/boot/loader/io/ata.asm
+++ /dev/null
@@ -1,159 +0,0 @@
-;=----------------------------------------------------------------------------=;
-; GNU GPL OS/K ;
-; ;
-; Desc: Basic Read Only ATA Long mode Driver ;
-; (x86_64 architecture only) ;
-; ;
-; ;
-; Copyright © 2018-2019 The OS/K Team ;
-; ;
-; This file is part of OS/K. ;
-; ;
-; OS/K is free software: you can redistribute it and/or modify ;
-; it under the terms of the GNU General Public License as published by ;
-; the Free Software Foundation, either version 3 of the License, or ;
-; (at your option) any later version. ;
-; ;
-; OS/K is distributed in the hope that it will be useful, ;
-; but WITHOUT ANY WARRANTY; without even the implied warranty of ;
-; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;
-; GNU General Public License for more details. ;
-; ;
-; You should have received a copy of the GNU General Public License ;
-; along with OS/K. If not, see . ;
-;=----------------------------------------------------------------------------=;
-
-[BITS 64]
-
-;; BPB
-%define OEMName bp+0x03 ; Disk label
-%define bytesPerSector bp+0x0b ; Bytes per sector
-%define sectorsPerCluster bp+0x0d ; Sectors per cluster
-%define reservedSectors bp+0x0e ; Reserved sectors
-%define fats bp+0x10 ; Number of fats
-%define rootDirEntries bp+0x11 ; Number of entries in root dir
-%define sectors bp+0x13 ; Logical sectors
-%define mediaType bp+0x15 ; Media descriptor byte
-%define fatSectors bp+0x16 ; Sectors per FAT
-%define sectorsPerTrack bp+0x18 ; Sectors per track
-%define heads bp+0x1a ; Number of sides/heads
-%define hiddenSectors bp+0x1c ; Hidden sectors
-%define hugeSectors bp+0x20 ; LBA sectors
-%define biosBootdrvNum bp+0x24 ; Bootdrv number
-%define reserved bp+0x25 ; This is not used
-%define bootSignature bp+0x26 ; Bootdrv signature
-%define volumeId bp+0x27 ; Volume ID
-%define volumeLabel bp+0x2b ; Volume Label
-%define fatTypeLabel bp+0x36 ; File system type
-
-;; GLOBAL DATA
-
-Bootdrv db 0
-ended db "[End of Sector]", 0x0A, 0x0A, 0x0D, 0x0
-buffer: times 513 db "_"
-
-;; TEXT
-
-ata_read:
-;-----------------------------------------------------------------------;
-; x64/LM ATA Reading function ;
-; bl : number of sectors to read XXX ;
-; bh : the first sector to read ;
-;-----------------------------------------------------------------------;
-
-; Technical infos about the ports (Intel Doc):
-;
-; Port Access Mode Misc
-;
-; 1f0 r/w Data register, the bytes of the disk itself
-; 1f1 r Error register that can be handled
-; 1f2 r/w Sector count, how many sectors to read
-; 1f3 r/w Sector number, the actual sector wanted
-; 1f4 r/w Cylinder low, cylinders is 0-1024
-; 1f5 r/w Cylinder high, this makes up the rest of the 1024
-; 1f6 r/w Drive/head
-; bit 7 = 1
-; bit 6 = 0
-; bit 5 = 1
-; bit 4 = 0 drive 0 select
-; = 1 drive 1 select
-; bit 3-0 head select bits
-; 1f7 r Status register
-; bit 7 = 1 controller is executing a command
-; bit 6 = 1 drive is ready
-; bit 5 = 1 write fault
-; bit 4 = 1 seek complete
-; bit 3 = 1 sector buffer requires servicing
-; bit 2 = 1 disk data read corrected
-; bit 1 = 1 index - set to 1 each revolution
-; bit 0 = 1 previous command ended in an error
-; 1f7 w Command register
-; commands:
-; 50h format track
-; 20h read sectors with retry
-; 21h read sectors without retry
-; 22h read long with retry
-; 23h read long without retry
-; 30h write sectors with retry
-; 31h write sectors without retry
-; 32h write long with retry
-; 33h write long without retry
-;
- push rax
- push rbx
- push rcx
- push rdx
- push rdi
- mov dx, 0x1f6 ; Drive and head port
- mov al, 0x0a0 ; Drive 0, head 0
- out dx,al
-
- mov dx, 0x1f2 ; Sector count port
- mov al, bl ; Read bl(s) sector
- out dx, al
-
- mov dx, 0x1f3 ; Sector number port
- mov al, bh ; Read from sector n°bh
- out dx, al
-
- mov dx, 0x1f4 ; Cylinder low port
- mov al, 0 ; Cylinder 0
- out dx, al
-
- mov dx, 0x1f5 ; Cylinder high port
- mov al, 0 ; The rest of the cylinder 0
- out dx, al
-
- mov dx, 0x1f7 ; Command port
- mov al, 0x20 ; Read with retry.
- out dx, al
-still_going:
- in al, dx
- test al, 8 ; This means the sector buffer requires
- ;servicing.
- jz still_going ; Don't continue until the sector buffer
- ;is ready.
-
- mov cx, 512/2 ; One sector /2 because it copies words
- mov rdi, QWORD buffer
- mov dx, 0x1f0 ; Data port - data comes in and out of here.
- rep insw
- pop rdi
-%ifdef DEBUG
- mov bl, 0x0F
- mov esi, buffer
- call dump
- mov bl, 0x0A
- mov esi, ended
- call write
- add qword [NextTRAM], 120 ; Cursor moving : 1120 = 80 * 2 * 7 lignes
-%else
- mov bl, 0x0A
- mov esi, Pass
- call write
-%endif
- pop rdx
- pop rcx
- pop rbx
- pop rax
- ret
diff --git a/boot/loader/io/lmmem.asm b/boot/loader/io/lmmem.asm
deleted file mode 100644
index e77e4c2..0000000
--- a/boot/loader/io/lmmem.asm
+++ /dev/null
@@ -1,43 +0,0 @@
-;=----------------------------------------------------------------------------=;
-; GNU GPL OS/K ;
-; ;
-; Desc: Basic Memory Long mode Functions ;
-; (x86_64 architecture only) ;
-; ;
-; ;
-; Copyright © 2018-2019 The OS/K Team ;
-; ;
-; This file is part of OS/K. ;
-; ;
-; OS/K is free software: you can redistribute it and/or modify ;
-; it under the terms of the GNU General Public License as published by ;
-; the Free Software Foundation, either version 3 of the License, or ;
-; (at your option) any later version. ;
-; ;
-; OS/K is distributed in the hope that it will be useful, ;
-; but WITHOUT ANY WARRANTY; without even the implied warranty of ;
-; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;
-; GNU General Public License for more details. ;
-; ;
-; You should have received a copy of the GNU General Public License ;
-; along with OS/K. If not, see . ;
-;=----------------------------------------------------------------------------=;
-[BITS 64]
-
-;; GLOBAL DATA
-A20_OK db 0
-
-;; TEXT
-
-check_a20:
- cmp BYTE [A20_OK], 1
- je .A20Success
- mov bl, 0x0C
- mov esi, Fail
- call write
- jmp Die
-.A20Success:
- mov bl, 0x0A
- mov esi, Pass
- call write
- ret
diff --git a/boot/loader/io/lmterm.asm b/boot/loader/io/lmterm.asm
deleted file mode 100644
index c5805d8..0000000
--- a/boot/loader/io/lmterm.asm
+++ /dev/null
@@ -1,131 +0,0 @@
-;=----------------------------------------------------------------------------=;
-; GNU GPL OS/K ;
-; ;
-; Desc: Basic Colored VGA Terminal Long mode Driver ;
-; (x86_64 architecture only) ;
-; ;
-; ;
-; Copyright © 2018-2019 The OS/K Team ;
-; ;
-; This file is part of OS/K. ;
-; ;
-; OS/K is free software: you can redistribute it and/or modify ;
-; it under the terms of the GNU General Public License as published by ;
-; the Free Software Foundation, either version 3 of the License, or ;
-; (at your option) any later version. ;
-; ;
-; OS/K is distributed in the hope that it will be useful, ;
-; but WITHOUT ANY WARRANTY; without even the implied warranty of ;
-; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;
-; GNU General Public License for more details. ;
-; ;
-; You should have received a copy of the GNU General Public License ;
-; along with OS/K. If not, see . ;
-;=----------------------------------------------------------------------------=;
-
-
-;;VIDEO
-%define TRAM 0x0B8000 ; [T]ext[RAM]
-%define VRAM 0x0A0000 ; [V]ideo[RAM]
-
-;; GLOBAL DATA
-
-VGA_HEIGHT dq 0
-VIDEO_MODE dw 0
-VIDEO_MODE32 dw 0
-VGA_HEIGHT32 dw 0
-NextTRAM dq 0x0B8000 ; Last position of cursor
-VIDEO_MODE64 dq 0
-VGA_HEIGHT64 dq 0
-VGA_X dq 0
-
-;; TEXT
-
-[BITS 64]
-
-clear:
-;-----------------------------------------------------------------------;
-; x64/LM Clear Text Screen Function ;
-;-----------------------------------------------------------------------;
- mov qword [NextTRAM], TRAM
- mov edi, TRAM
- push rsi
- push rdi
- push rcx
- mov ah, 0
- mov al, 0
- mov rcx, 0x4000 ; traditionnal value
- rep stosw ; fill screen with al while cx > 0
- pop rcx
- pop rsi
- pop rdi
- ret
-
-write:
-;-----------------------------------------------------------------------;
-; x64/LM Text Printing Functions ;
-; bl : color code ;
-; esi : string address ;
-;-----------------------------------------------------------------------;
- mov edi, [NextTRAM] ; TRAM ADDRESS
- push rsi
- push rdi
-.pLoop:
- lodsb
- cmp al, 0 ; while @al, i.e. while we're not hitting '\0'
- je .pEnd
- cmp al, 0x0A ; LF
- je .lf
- cmp al, 0x0D ; CR
- je .cr
- stosb ; text subpixel
- mov al, bl
- stosb ; color subpixel
- add qword [NextTRAM], 0x2 ; Cursor moving
- add qword [VGA_X], 0x2 ; coord + 2 because 2 subpixels
- jmp .pLoop
-.pEnd:
- pop rdi
- pop rsi
- ret
-.lf:
- mov rax, [VGA_HEIGHT64]
- add [NextTRAM], rax ; Cursor moving
- add [NextTRAM], rax
- add edi, eax ; Address moving
- add edi, eax
- jmp .pLoop
-.cr:
- push rax
- mov rax, qword [VGA_X]
- sub qword [NextTRAM], rax ; pos = X + Y * VGA_HEIGHT64. Donc pos - X = début de ligne
- sub edi, edx
- mov qword [VGA_X], 0
- pop rax
- jmp .pLoop
-.scroll:
- ; XXX I don't think I'll implement this, but never know...;
- jmp .pLoop
-
-dump:
-;-----------------------------------------------------------------------;
-; x64/LM Dump 512 bytes of a buffer ;
-; bl : color code ;
-; esi : buffer address ;
-;-----------------------------------------------------------------------;
- mov edi, [NextTRAM] ; TRAM ADDRESS
- push rsi
- push rdi
- push rcx
- mov rcx, 512
-.pLoop:
- lodsb
- stosb ; text subpixel
- mov al, bl
- stosb ; color subpixel
- loop .pLoop
- pop rcx
- pop rdi
- pop rsi
- add qword [NextTRAM], 1000 ; Cursor moving : 1120 = 80 * 2 * 7 lignes
- ret
diff --git a/boot/loader/loader.asm b/boot/loader/loader.asm
index 2040668..d421bd0 100644
--- a/boot/loader/loader.asm
+++ b/boot/loader/loader.asm
@@ -31,7 +31,7 @@
%include "boot/loader/multiboot/header.inc"
-;; Normal entry point, but a little bit unused since we never use it because...
+;; NORMAL ENTRY POINT, BUT A LITTLE BIT UNUSED SINCE WE NEVER USE IT BECAUSE...
_start:
mov ax, cs ; correcting cs after the horrible far jump
mov ds, ax ; hm... And ds too
@@ -40,7 +40,7 @@ _start:
xor dl, dl
jmp 0x0000:_loader ; pas sûr
-;; Magnificent multiboot header for GRUB ------------------------------------ ;;
+;; MAGNIFICENT MULTIBOOT HEADER FOR GRUB ------------------------------------ ;;
MB_header:
align 4
dd MB_HEADER_MAGIC
@@ -52,7 +52,7 @@ MB_header:
dd 00 ; (bss) not necessary
dd MB_start ; entry address GRUB will start at
-;; Multiboot entry point for Grub ------------------------------------------- ;;
+;; MULTIBOOT POINT ENTRY FOR GRUB ------------------------------------------- ;;
MB_start:
mov esp, KERNEL_STACK ; Setup the stack
push 0 ; Reset EFLAGS
@@ -65,13 +65,22 @@ MB_start:
jmp Die ; Aufwiedersehen
;; THE HOLES ---------------------------------------------------------------- ;;
+
+; ---------------------------------------------------------------------------- ;
+; Prints 'ERR:XX' where 'XX' is the str in AX ;
+; ---------------------------------------------------------------------------- ;
Error:
mov dword [0xb8000], 0x4f524f45
mov dword [0xb8004], 0x4f3a4f52
mov dword [0xb8008], 0x4f204f20
mov byte [0xb800a], al
+ mov byte [0xb800c], ah
+ mov byte [0xb800d], 0x4f
jmp Die
+; ---------------------------------------------------------------------------- ;
+; Kills the mind of your computer to get it prostrated ;
+; ---------------------------------------------------------------------------- ;
Die:
cli
hlt ; die nooooow
@@ -95,24 +104,57 @@ _loader:
jmp lbegin
%include "boot/loader/multiboot/check.inc"
-lbegin:
- call MB_check
- jmp lnext
-
%include "boot/loader/cpu/cpuid.inc"
-lnext:
- call Check_cpuid
- call Is64Bits
- jmp lnext2
-
%include "boot/loader/mem/structures.inc"
-lnext2:
- call Setup_paging
- call Go64
- jmp lnext3
%include "boot/loader/mem/management.inc"
-lnext3:
- mov dword [0xb8000], 0x2f4b2f4f
- ret
+lbegin:
+ call MB_check
+ call Check_cpuid
+ call Is64Bits
+ call CheckA20
+
+ call Setup_paging
+ call Go64
+
+ lgdt [GDT64.pointer]
+ jmp GDT64.code:l64
+
+[BITS 64]
+%include "boot/loader/io/terminal.inc"
+%include "boot/loader/io/ata.inc"
+%include "boot/loader/cpu/cpu.inc"
+
+Salut db 0x09, " Booting OS/K ", 0x09, 0x0A, 0x0D, 0x0
+ReadAttempt db 0x09, " Attempt to read a sector with ATA commands...", 0
+
+l64:
+ ;; Some cleanup
+ mov ax, 0
+ mov ss, ax
+ mov ds, ax
+ mov es, ax
+ mov fs, ax
+ mov gs, ax
+
+ ;; Hello world
+ mov bl, 0x0A
+ mov esi, Salut
+ call write
+
+ ;; Read ATA
+ mov bl, 0x0F
+ mov esi, ReadAttempt
+ call write
+
+ call temporize
+
+
+
+ ;; Reading a sector of the disk
+ mov bl, 1
+ mov bh, 1
+ call ata_read
+
+ jmp Die
diff --git a/boot/loader/mem/management.inc b/boot/loader/mem/management.inc
index 48ff4cc..57f86d7 100644
--- a/boot/loader/mem/management.inc
+++ b/boot/loader/mem/management.inc
@@ -87,3 +87,22 @@ Go64:
popa
ret
+
+; ---------------------------------------------------------------------------- ;
+; Checks if Grub has enabled A20 line ;
+; ---------------------------------------------------------------------------- ;
+CheckA20:
+ pushad
+ mov edi,0x112345 ;odd megabyte address.
+ mov esi,0x012345 ;even megabyte address.
+ mov [esi],esi ;making sure that both addresses contain diffrent values.
+ mov [edi],edi ;(if A20 line is cleared the two pointers would point to the address 0x012345 that would contain 0x112345 (edi))
+ cmpsd ;compare addresses to see if the're equivalent.
+ popad
+ jne .A20_on ;if not equivalent , A20 line is set.
+ jmp .A20_err
+.A20_on:
+ ret
+.A20_err:
+ mov ax, "03" ; ERROR 03 : A20 line failed
+ jmp Error
diff --git a/boot/loader/mem/structures.inc b/boot/loader/mem/structures.inc
index 4947b9d..e1be0bd 100644
--- a/boot/loader/mem/structures.inc
+++ b/boot/loader/mem/structures.inc
@@ -28,80 +28,20 @@
;; GDT WITH DOC
ALIGN 4096
GDT64:
- NULL_SELECTOR: ;; null selector within 64 bits
- dw GDT_LENGTH ; limit of GDT
- dw GDT64 ; linear address of GDT
- dd 0x0 ;
-
- CODE_SELECTOR: ;; 32-bit code selector (ring 0)
- dw 0x0000FFFF ; Segment Limit
- db 0x0, 0x0, 0x0 ; Base Address
- db 10011010b ; |7|6|5|4|3|2|1|0|
- ; | | | | | | | `----- 1 when segment used.
- ; | | | | | | `------ 1 when writable.
- ; | | | | | `------- 1 if "conformant". Don't know what is it... spectral ? xD
- ; | | | | `-------- 1 always
- ; | | | `--------- 1 for segment descriptor, 0 for system descriptor
- ; | | `---------- DPL !!! 0 for ring 0
- ; | `----------- DPL (2/2)
- ; `------------ 1 if in physical memory, 0 if page fault
- db 11001111b ; |7|6|5|4|3|2|1|0|
- ; | | | | | | | `----- Limit 16
- ; | | | | | | `------ Limit 17
- ; | | | | | `------- Limit 18
- ; | | | | `-------- Limit 19
- ; | | | `--------- available for use
- ; | | `---------- 0 always
- ; | `----------- size of data. 1 for 32bits
- ; `------------ 0 if limit is in Bytes, 1 if it's in pages (4ko)
- db 0x0 ; Base Address
-
- DATA_SELECTOR: ;; flat data selector (ring 0)
- dw 0x0000FFFF ; Segment Limit
- db 0x0, 0x0, 0x0 ; Base Address
- db 10010010b ; |7|6|5|4|3|2|1|0|
- ; | | | | | | | `----- 1 when segment used.
- ; | | | | | | `------ 1 when writable.
- ; | | | | | `------- expansion direction. 1 for a LIFO
- ; | | | | `-------- 1 always
- ; | | | `--------- 1 for segment descriptor, 0 for system descriptor
- ; | | `---------- DPL !!! 0 for ring 0
- ; | `----------- DPL (2/2)
- ; `------------ 1 if in physical memory, 0 if page fault
- db 10001111b ; |7|6|5|4|3|2|1|0|
- ; | | | | | | | `----- Limit 16
- ; | | | | | | `------ Limit 17
- ; | | | | | `------- Limit 18
- ; | | | | `-------- Limit 19
- ; | | | `--------- available for use
- ; | | `---------- 0 always
- ; | `----------- size of data. 1 for 32bits
- ; `------------ 0 if limit is in Bytes, 1 if it's in pages (4ko)
- db 0x0 ; Base Address
-
- LONG_SELECTOR: ;; 64-bit code selector (ring 0)
- dw 0x0000FFFF ; Segment Limit
- db 0x0, 0x0, 0x0 ; Base Address
- db 10011010b ; |7|6|5|4|3|2|1|0|
- ; | | | | | | | `----- 1 when segment used.
- ; | | | | | | `------ 1 when writable.
- ; | | | | | `------- 1 if "conformant". Don't know what is it... spectral ? xD
- ; | | | | `-------- 1 always
- ; | | | `--------- 1 for segment descriptor, 0 for system descriptor
- ; | | `---------- DPL !!! 0 for ring 0
- ; | `----------- DPL (2/2)
- ; `------------ 1 if in physical memory, 0 if page fault
- db 10101111b ; |7|6|5|4|3|2|1|0|
- ; | | | | | | | `----- Limit 16
- ; | | | | | | `------ Limit 17
- ; | | | | | `------- Limit 18
- ; | | | | `-------- Limit 19
- ; | | | `--------- available for use
- ; | | `---------- 0 always
- ; | `----------- size of data. 1 for 32bits
- ; `------------ 0 if limit is in Bytes, 1 if it's in pages (4ko)
- db 0x0 ; Base Address
- GDT_LENGTH:
+ ;; Null selector within 64 bits
+ .null:
+ dq 0x0 ; Zero entry
+ ;; 64-bit code selector (ring 0)
+ .code: equ $ - GDT64
+ dq (1<<43) | (1<<44) | (1<<47) | (1<<53)
+ ; | | | |
+ ; | | | `------ 64-bit selector
+ ; | | `---------------- Present selector
+ ; | `-------------------------- Descriptor type
+ ; `------------------------------------ Executable segment
+ .pointer:
+ dw $ - GDT64 - 1
+ dq GDT64
;; EMPTY PAGE TABLES (identity of the first 1GiB)
ALIGN 4096
diff --git a/boot/loader/multiboot/check.inc b/boot/loader/multiboot/check.inc
index e1b42e3..c045e64 100644
--- a/boot/loader/multiboot/check.inc
+++ b/boot/loader/multiboot/check.inc
@@ -31,5 +31,5 @@ MB_check:
jne .no_MB
ret
.no_MB:
- mov al, "0" ; ERROR 0 : No multiboot
+ mov ax, "01" ; ERROR 01 : No multiboot
jmp Error
diff --git a/build/obj/boot/loader.bin b/build/obj/boot/loader.bin
index 1b1f118..aa06194 100644
Binary files a/build/obj/boot/loader.bin and b/build/obj/boot/loader.bin differ