Re: ia32 suffix inconsistency

["Jan Beulich" <JBeulich at novell dot com>]

>>> On 15.12.10 at 16:08, "H.J. Lu" <hjl.tools@gmail.com> wrote:
> On Wed, Dec 15, 2010 at 3:11 AM, Etienne Lorrain
> <etienne_lorrain@yahoo.fr> wrote:
>> Hello,
>>
>> Just a small detail I think I have to report, with:
>> GNU assembler (GNU Binutils for Debian) 2.20.1-system.20100303
>> This assembler was configured for a target of `i486-linux-gnu'
>> It is not a regression, i.e. same behaviour for years.
>>
>> We have to postfix 'l' (or 'w' or 'b') when using a simple 'mov' or 'test':
>> $ echo 'mov $1,(%ebx)' | as
>> {standard input}: Assembler messages:
>> {standard input}:1: Error: no instruction mnemonic suffix given and no 
> register operands; can't size instruction
>> $ echo 'movl $1,(%ebx)' | as
>> $ echo 'test $1,(%ebx)' | as
>> {standard input}: Assembler messages:
>> {standard input}:1: Error: no instruction mnemonic suffix given and no 
> register operands; can't size instruction
>> $
> 
> Those insns don't extend immX to 32bit/64bit.
> 
>> but other instructions like and/cmp/xor/or should also need such suffix, 
> isn't it?
>> $ echo 'and $1,(%ebx)' | as
>> $ echo 'cmp $1,(%ebx)' | as
>> $ echo 'xor $1,(%ebx)' | as
>> $ echo 'or $1,(%ebx)' | as
> 
> Those insns extend immX to 32bit first.

But whether an extension of the immediate happens shouldn't
matter for diagnostics to be generated: It is as bogus to write

	mov	$1, (%eax)

as it is for

	add	$1, (%eax)

yet in one case the assembler *guesses* what the programmer
meant whereas in the other case it errors out.

I'm pretty positive that in Intel syntax mode this is more
consistent (no guessing on the part of the assembler at all).

Jan