Re: [Pgubook-readers] Issue With 1st Example

[Bryn M. Reeves]

On Wed, 2010-02-10 at 09:19 -0700, address@hidden wrote:
> Hello,
> 
> I'm having some issues with the first actual example assembly program
>  in the text, namely that when I run it through the assembler, this is
>  what I'm getting:
> 
> address@hidden:~/asm> as exit.s -o exit.o
> exit.s: Assembler messages:
> exit.s:0: Warning: end of file in comment; newline inserted
> exit.s:25: Error: no such instruction: `mov1 $1,%eax'
> exit.s:29: Error: no such instruction: `mov1 $0,%ebx'
> address@hidden:~/asm>
> 
> I'm not quite sure why this is happening, so I've attached my source
>  file to this message, which I created and attempted to assemble using
>  kwrite on my 32-bit openSUSE installation.  Please let me know why
>  this is happening, so I can continue learning assembly with confidence
>  in my materials.
> 
> ~Wesley

Hi Wesley,

Looks like a minor typo - those are "l"s (lowercase L) on the end of the
mov instruction not "1"s (numeral one) - it should read "movl". The
error you are getting is because "mov1" isn't recognised as a valid x86
assembler mnemonic.

The full name of the instruction is "move long".

Corrected version (assembles, links & runs here) attached:

$ as -o exit.o exit.s 
$ ld -o exit exit.o 
$ ./exit 
$ echo $?
0
$ objdump -d ./a.out

./a.out:     file format elf64-x86-64


Disassembly of section .text:

0000000000400078 <_start>:
  400078:       b8 01 00 00 00          mov    $0x1,%eax
  40007d:       bb 00 00 00 00          mov    $0x0,%ebx
  400082:       cd 80                   int    $0x80


Cheers,
Bryn.

exit.s
Description: Text document