Ed Beroset writes:
> That's further than I get.  Here's what happens when I attempt to
> assemble this under Linux (two different versions of the RedHat
> distribution, FWIW) using the GNU assembler, version 2.7:
GNU assembler version 970202 (i486-linux), using BFD version 2.7.0.9
This is from Debian Linux 1.3
> It seems to me that GAS, at least the version I have, just isn't up to the 
> task.  I wonder if this isn't the root of Paul's problems?
I came to the same conclusion-- it's making 32-bit memory references
despite the .code16 directive.  So I tried a Nasm0.94 version, which
assembles correctly but I think it jams because of the load address,
we need to setup the offsets.....
;
;nasm -f bin setup2.asm -o setup2.bin
;
;
bits 16
section .text 
global _start
;org 0x100
_start:
    
mov ax,cs
mov ds,ax
mov es,ax
mov ss,ax
mov sp,0xfff0
mov ah,0x3
mov bh,0x0
int 0x10
mov ax,0x1301
mov bx,0x7
mov bp,msg                      ; + offset
mov cx,[ msg_length ]           ; + offset
int 0x10
cli
mov al,0x80
out 0x70,al
lgdt [ gdt_descriptor ]         ; + offset
lidt [ idt_descriptor ]         ; + offset
o32 mov eax,cr0
or al,0x1
o32 mov cr0,eax
;jmp dword 0x8:0x1000
jmp $
gdt_descriptor  dw  0x0017
                dd  0x00000000
                dd  0x00000000
                dd  0x00CF9A00
                dd  0x00000FFF
                dd  0x00CF9200
                dd  0x00000FFF
idt_descriptor  dw  0x0000
                dd  0x00000000                                            
 
msg db 'Entering protected mode...',0x0D,0x0A
                           
msg_length  dw  $ - msg
  
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