Re: [Nasm-devel] Re: nasm / ndisasm

[Ben L. <fy...@cy...>]

----- Original Message ----- 
From: "John Coffman" <joh...@sa...>
To: "Frank Kotler" <fbk...@at...>
Cc: "Ben Lunt" <fy...@cy...>; <nas...@li...>
Sent: Monday, May 26, 2003 8:48 AM
Subject: Re: [Nasm-devel] Re: nasm / ndisasm


Hi John, Hi Frank

> Note that the encoding for
>
>          SMSW    eax
> and
>          SMSW    ax
>
> are identical.  Hence it is the same instruction.

Agreed.

> It would be the only instruction where EAX is specified, but only the AX
> portion is modified.
>
> Whether the 32 bit form is accepted by the assembler is strictly a
> stylistic argument.  But the 32 bit form should be flagged so it is ignored
> by the disassembler.  "ND", I believe, is the spec.

This is where the question is.  Should an assembler allow EAX and AX
or just AX.  When I write 32-bit code, where most of the registers
are 32-bit, I tend to use a 32-bit register where the 16-bit counterpart
will do.  Just habit.

So I guess the question is, should an assembler allow the r32 also?

Cheers,
Ben