diff --git a/LINES b/LINES
index b384f384bdc36acb63ff2b86f2fa3b37a6cb8d00..61f948d1882d95a796c66c98a6d0ea9690672d3f 100644
--- a/LINES
+++ b/LINES
@@ -8,3 +8,5 @@
 
 2021-2-15 0.451: 451 lines, 4 files, rain
 
+2021-2-15 0.466: 466 lines, 5 files, rain
+
diff --git a/README.md b/README.md
index 3d6748db64e454ef673e56f4be9d6fac74663d85..da87d307ec4767c40f06d9d9414a05fbcd2bb853 100644
--- a/README.md
+++ b/README.md
@@ -23,4 +23,6 @@ Cunix kernel
 `0.451s-boot`:  
 &#9`boot` can load 8 sectors (4KB) of loader (not 1 sector).  
 
+`0.466s-boot`:
+&#9rebuild `boot`
 </pre>
diff --git a/boot/x86/boot.asm b/boot/x86/boot.asm
index e32a117bcf37a127e174755bcd9932d3eb312431..386a0fb6261988c525afd8e3c9401381575f11c9 100644
--- a/boot/x86/boot.asm
+++ b/boot/x86/boot.asm
@@ -17,38 +17,38 @@
 
 
 
-BI_BOOTDEV equ 0x7e00
-
 org 0x7c00
 
+_start:
+	xor ax, ax
 
-xor ax, ax
-
-mov ds, ax
-mov es, ax
+	mov ds, ax
+	mov es, ax
 
-mov ss, ax
-mov sp, 0x7c00
+	mov ss, ax
+	mov sp, 0x7c00
 
-; display message: `Cunix is booting...`
+	; display message: `Cunix is booting...`
 
 
-; boot device driver number is in DL (by BIOS-19)
-mov [BI_BOOTDEV], dl
+	; boot device driver number is in DL (by BIOS-19)
+	mov [BI_BOOTDEV], dl
 
 
-mov si, message
-call print
+	mov si, message
+	call print
 
-call load_loader
+	call load_loader
 
-jmp 0x0000:0x8000
+	jmp 0x0000:0x8000
 
 
 message: db "Cunix is booting...", 0x0d, 0x0a, 0x00
 diskpanic_message: db "read disk failed", 0x0d, 0x0a, 0x00
 panic_message: db "panic: ", 0x00
 
+%include "arch/x86/readdisk.inc"
+
 print:
 	; SI: message address
 	mov al, [si]
@@ -71,12 +71,11 @@ load_loader:
 	mov cl, 0x02
 	mov bx, 0x8000
 
-.read_loop:
-	call read_sector_chs
-
 	mov di, diskpanic_message
 
-	jc .try_lba
+.read_loop:
+	call read_sector
+	jc panic
 
 ; read 8 sectors
 	add cl, 0x02
@@ -91,52 +90,6 @@ load_loader:
 	ret
 	
 
-.try_lba:
-	call read_sector_lba
-
-	jc panic
-
-	add cl, 0x02
-	add bx, 0x0200
-	
-	cmp cl, 0x0a
-	je .ret
-	
-	jmp .read_loop
-	
-	
-
-read_sector_chs:
-	mov ax, 0x0201
-	xor ch, ch
-	; CL is argument `start sector`
-	xor dh, dh
-
-	mov dl ,[BI_BOOTDEV]
-
-	int 0x13
-	ret
-	
-
-read_sector_lba:
-	push dword 0x00000000
-	; ECX is argument `LBA address`
-	push dword ecx
-	push word es
-	push word bx
-	; 1 sector
-	push word 0x0001
-	push word 0x0010
-
-	mov ah, 0x42
-	mov dl, [BI_BOOTDEV]
-	mov si, sp
-	int 0x13
-	add sp, 0x10
-
-	ret
-
-
 panic:
 	mov si, panic_message
 	call print
diff --git a/include/arch/x86/readdisk.inc b/include/arch/x86/readdisk.inc
new file mode 100644
index 0000000000000000000000000000000000000000..f1c411a0e29c5460f56735682578bdcd627884ae
--- /dev/null
+++ b/include/arch/x86/readdisk.inc
@@ -0,0 +1,62 @@
+; Copyright (C) 2021 Rain
+
+; This file is part of Cunix. 
+
+; Cunix is free software: you can redistribute it and/or modify 
+; it under the terms of the GNU General Public Licene and published by 
+; the Free Software Foundation, either version 3 of the License, or 
+; (at your option) any later version. 
+
+; Cunix 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 recceived a copy of the GNU General Public License 
+; along with Cunix. If not, see <https://www.gnu.org/licenses/>. 
+
+
+
+
+BI_BOOTDEV equ 0x7e00
+
+read_sector:
+	; CH is sector number
+	call read_sector_chs
+	jc .try_lba
+
+	ret
+
+.try_lba:
+	call read_sector_lba
+	ret
+
+read_sector_chs:
+	mov ax, 0x0201
+	xor ch, ch
+
+	xor dh, dh
+
+	mov dl, [BI_BOOTDEV]
+	
+	int 0x13
+	ret
+
+read_sector_lba:
+	push dword 0x00000000
+	push dword ecx
+	push word es
+	push word bx
+
+	push word 0x0001
+	push word 0x0010
+	
+	mov ah, 0x42
+	mov dl, [BI_BOOTDEV]
+
+	int 0x13
+	add sp, 0x10
+
+	ret
+
+