NOTE: It doesn't report, "File not found!" error. So I don't know why it hangs.
Here is what it displays on stage 2..
Code: Select all
A20 is enabled.
Loading kernel, please waitstage2.asm
Code: Select all
; stage 2 boot loader.
; by Philip Simonson.
; =======================
[org 0x7e00]
[bits 16]
start:
mov [iBootDrive], dl
; set text mode (80x25)
mov ax, 0x0003
int 0x10
call reset_disk
call a20_bios
call check_a20
mov si, op_loading
call print
call load_file
; switch on protected mode
cli
lgdt [gdt.pointer]
mov eax, cr0
or eax, 1
mov cr0, eax
jmp dword 0x08:INIT_PM
%include "common.inc"
%include "disk.inc"
%include "a20.inc"
%include "gdt.inc"
[bits 32]
INIT_PM:
mov ax, 0x10
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax
mov ebp, 0x90000
mov esp, ebp
call run_offset
hlt
%include "common32.inc"
; data
op_loading db "Loading kernel, please wait",0
op_done db "done!",10,13,0
op_a20yes db "A20 is enabled.",10,13,0
op_a20no db "A20 is disabled.",10,13,0
op_progress db 0x2e,0
op_ferror db 10,13,"File not found!",10,13,0
op_filename db "kernel bin",0
; constants
root_segment equ 0x0ee0
root_offset equ 0x0000
load_segment equ 0x1000
load_offset equ 0x0000
run_offset equ 0x00010000
%include "bs.inc"
Code: Select all
; simple BIOS disk services
; ======================================
; reset disk drive
; ======================================
reset_disk:
push ax
xor ax, ax
mov dl, [iBootDrive]
int 0x13
pop ax
ret
; ==================================================
; Description: Load a file from my file table.
; No parameters.
; ==================================================
load_file:
mov bx, root_segment
mov es, bx
mov bx, root_offset
.loop:
mov al, [bx]
cmp al, 0x0
je .error
mov cx, 11
mov di, bx
mov si, op_filename
rep cmpsb
je .found
add bx, 16
jmp short .loop
.found:
mov ax, word [es:bx+0x0c]
mov cx, word [es:bx+0x0e]
mov bx, load_segment
mov es, bx
mov bx, load_offset
call read_disk
ret
.error:
mov si, op_ferror
call print
ret
; ==================================================
; Description: Load file from disk using LBA.
; ax - LBA (Logical Block Address)
; cx - Number of sectors to read.
; [es:bx] - Location to store at (in memory).
; ==================================================
read_disk:
mov di, 5
.loop:
push ax
push cx
push bx
; calculate sector
mov bx, word [iTrackSect]
xor dx, dx
div bx
inc dx
mov cl, dl
; calculate track/head
mov bx, word [iHeadCnt]
xor dx, dx
div bx
mov ch, al
xchg dl, dh
; read sector
mov ax, 0x0201
mov dl, byte [iBootDrive]
pop bx
int 0x13
jnc .success
xor ax, ax
int 0x13
dec di
pop cx
pop ax
cmp di, 0
jne .loop
mov si, op_ferror
call print
jmp $
.success:
mov si, op_progress
call print
pop cx
pop ax
inc ax
add bx, word [iSectSize]
loop read_disk
mov si, op_done
call print
ret
- Phil
