kernel working

bootloader/boot.asm

 [bits 16]
 [org 0x7c00]
 
-mov [_boot_drive_id], dl
-    ; Load the kernel image from boot disk, disk offset 512B to 64KB.
-    KERN_ADDR equ 0x7e00
-    mov ah, 0x02
-    mov dl, [_boot_drive_id]
-    mov ch, 0
-    mov dh, 0
-    mov cl, 2 ; from the second one,
-    mov al, 127 ; read 127 sectors in total.
-    mov bx, KERN_ADDR
-    int 0x13 ; Set carry on error, and set AL to sectors that actual read.
+KERN_ADDR equ 0x7e00
 
-    jc disk_io_error
-    mov dl, 0x7f
-    cmp dl, al
-    jne disk_io_error
-    ; kernel successfully loaded now!
-    mov bx, _motd_kern_ok
-    call println_bios
-
-jmp _init_prot_mode
+mov [_boot_drive_id], dl
+jmp _load_kern
+; jmp _init_prot_mode
 
 %include "./str.16.inc"
 
@@ -60,6 +44,35 @@ gdt_desc:
 CODE_SEG_OFFSET equ gdt_entry_1 - gdt_begin
 DATA_SEG_OFFSET equ gdt_entry_2 - gdt_begin
 
+_load_kern:
+    ; Load the kernel image from boot disk, disk offset 512B to 64KB.
+    ; This is a 16bit real mode function.
+    mov ah, 0x02
+    mov dl, [_boot_drive_id]
+    mov ch, 0
+    mov dh, 0
+    mov cl, 2 ; from the second one,
+    mov al, 127 ; read 127 sectors in total.
+    mov bx, KERN_ADDR
+    int 0x13 ; Set carry on error, and set AL to sectors that actual read.
+
+    jc disk_io_error
+    mov dl, 0x7f
+    cmp dl, al
+    jne disk_io_error
+    ; kernel successfully loaded now!
+    mov bx, _motd_kern_ok
+    call println_bios
+    jmp _init_prot_mode
+
+disk_io_error:
+    mov bx, _motd_disk_error
+    call println_bios
+    jmp _stall
+
+
+
+
 _init_prot_mode:
     cli
     lgdt [gdt_desc]
@@ -85,24 +98,24 @@ _prot_begin:
     mov ebx, _motd_32
     call println_vga
 
+    ; Enter the kernel. This should never return.
+    call KERN_ADDR
 
+    ; Kernel returns.
+    mov ebx, _motd_endk
+    call println_vga
 
 _stall:
     jmp $
 
-disk_io_error:
-    mov ebx, _motd_disk_error
-    call println_vga
-    jmp _stall
-
 _motd_disk_error:
     db 'DISK_IO_ERROR', 0x0
 _motd_32:
-    db '[ENTER X86 MODE SUCC]', 0x0
+    db '[LOAD KERN SUCC] [ENTER X86 MODE SUCC]', 0x0
 _motd_kern_ok:
-    db '[ENTER X86 MODE SUCC] [LOAD KERN SUCC]', 0x0
+    db '[LOAD KERN SUCC]', 0x0
 _motd_endk:
-    db '[ENTER X86 MODE SUCC] [LOAD KERN SUCC] [KERN EXITED]', 0x0
+    db '[LOAD KERN SUCC] [ENTER X86 MODE SUCC] [KERN EXITED]', 0x0
 _boot_drive_id:
     db 0x0