Hi All,

I am getting a compilation error in this file at the point i highlighted below..

i am trying to compile in linux 9 & pentium III amchine..

wt might be the reason for giving the error..???

please help me out>??

Thomas




boot/start.asm
; Copyright (C) 2002 Alexander Blessing
;
; called by bootloader (hopefully GRUB)
; jumps to main kernel after having set up some low-level stuff

[BITS 32] ; want 32 bit code
[global start] ; entry point
[extern kmain]
[extern disable_nmi]

section .text

start:
cli ; disable all interrupts
call disable_nmi
jmp over_data ; don't read the data stuff

; multiboot header for GRUB
MULTIBOOT_PAGE_ALIGN equ 1<<0
MULTIBOOT_MEMORY_INFO equ 1<<1
MULTIBOOT_HEADER_MAGIC equ 0x1BADB002

MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO
CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)

; build Multiboot header
align 4
dd MULTIBOOT_HEADER_MAGIC
dd MULTIBOOT_HEADER_FLAGS
dd CHECKSUM

over_data:
; check if we are called by GRUB
mov [mboot_info], ebx ; store multiboot info
cmp eax, 0x2BADB002
sete [mboot_valid]

; load our own GDT
; GRUB sets up one only temporarily
lgdt [gdt_ptr] ; now load the GDT...
mov ax,DS_SELECTOR ; ...and update segment registers
mov ds,ax
mov es,ax
mov ss,ax
mov fs,ax
mov gs,ax
jmp CS_SELECTOR:go_on ; do a JMP to initialize CS register

go_on:
; zero BSS
extern bss, kernel_end
mov edi,bss
mov ecx,kernel_end
sub ecx,edi
xor eax,eax
rep stosb

mov esp,stack_top ; and set up our stack

; now, let's set up an IDT
; up to now, we have 256 descriptors
; so first, fill every descriptor with
; a common interrupt handler routine
; afterwards, we'll change this
mov ecx,(idt_end - idt) >> 3 ; number of descriptors
mov edi,idt ; idt location
mov esi,common_isr ; common handler to esi

fill_idt:
mov eax,esi
mov [edi],ax ; low offset
shr eax,16
mov [edi+6],ax ; high offset
add edi,8 ; descriptor length
loop fill_idt

lidt [idt_ptr] ; ok, load the IDT

; that's it - do a jmp to the main C function
jmp kmain

common_isr:
; this is the common interrupt service routine
; this means, we haven't implemented this
; interrupt yet
; so we just return
iretd

section .data ; the data section

[global mboot_valid]
mboot_valid:
dd 0 ; for verification of a valid Multiboot header
[global mboot_info]
mboot_info:
dd 0 ; holds information about the Multiboot header

; Global Descriptor Table
gdt:
; NULL descriptor
dw 0
dw 0
db 0
db 0
db 0
db 0

[global DS_SELECTOR]
DS_SELECTOR equ $ - gdt
dw 0FFFFh
dw 0
db 0
db 92h ; present, ring 0, data, expand-up, writable
db 0CFh ; page-granular (4 gig limit), 32-bit
db 0

[global CS_SELECTOR]
CS_SELECTOR equ $ - gdt
dw 0FFFFh
dw 0
db 0
db 9Ah ; present,ring 0,code,non-conforming,readable
db 0CFh ; page-granular (4 gig limit), 32-bit
db 0

[global USER_DATA_SEL]
USER_DATA_SEL equ $ - gdt
dw 0FFFFh
dw 0
db 0
db 0F2h
db 0CFh
db 0

[global USER_CODE_SEL]
USER_CODE_SEL equ $ - gdt
dw 0FFFFh
dw 0
db 0
db 0FAh
db 0CFh
db 0

gdt_end:

<I AM GETTING AN ERROR IN "gdt_end "WHILE I COMPILE IN LINUX 9& IN PENTIUM MACHINE>



gdt_ptr:
dw gdt_end - gdt - 1
dd gdt

; Interrupt Descriptor Table
; have 256 descriptor here, all having
; the same interrupt handler
; will change this at runtime
[global idt]
idt:
%rep 256
dw 0 ; offset 15:0
dw CS_SELECTOR ; selector
dw 0x8E00 ; present, ring 0, '386 interrupt gate
dw 0 ; offset 31:16
%endrep
idt_end:

idt_ptr:
dw idt_end - idt - 1; IDT limit
dd idt ; start of IDT

section .bss
resb 8192 ; 8 kilobytes for stack
stack_top: ; top of our stack here