Re: PATCH: Modify GNU assembler to follow SVME spec

["H.J. Lu" <hjl at lucon dot org>]

On Wed, Sep 05, 2007 at 06:26:19PM +0100, Jan Beulich wrote:
> Based on the original discussion, where I convinced AMD (I don't remember who
> posted the patch back then) that accesses that are memory like should be
> represented by memory like operand syntax, I object to this patch. Jan
> 

You are confused by those instructions with the contents in their
register operands.  When the reg bits (bits 6 and 7) in MODRM byte
are 11, instructions will only take register operands.  It doesn't
matter if the contents in those registers are used as addresses by
those instructions.  The reg bits of MODRM byte in opcodes of those
SVME instructions are 11 so that they will only take register
operands.  For memory operand, the reg bits of MODRM byte can't be 11. 

BTW, AMD has confirmed that those SVME instructions only take
register operands.


H.J.