From 14a9ce27abe5d855d3c1b667989f85d41a09a8e0 Mon Sep 17 00:00:00 2001
From: Recolic Keghart <root@recolic.net>
Date: Tue, 9 Jun 2020 16:47:51 +0800
Subject: [PATCH] kernel working
---
bootloader/boot.asm | 69 +++++++++++++++++++++++++++------------------
1 file changed, 41 insertions(+), 28 deletions(-)
diff --git a/bootloader/boot.asm b/bootloader/boot.asm
index ae7b822..e321a10 100644
--- a/bootloader/boot.asm
+++ b/bootloader/boot.asm
@@ -1,27 +1,11 @@
[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
--
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