Re: [Qemu-devel] [PATCH 11/13] Add xxsel

[Tom Musta]

On 10/9/2013 3:13 PM, Richard Henderson wrote:
> On 10/04/2013 06:24 AM, Tom Musta wrote:
> > +    tcg_gen_and_i64(b, b, c);
> > +    tcg_gen_not_i64(c, c);
> > +    tcg_gen_and_i64(a, a, c);
> tcg_gen_andc_i64.
>
> > +#define GEN_XXSEL() \
> > +GEN_XXSEL_ROW(0x00) \
> > +GEN_XXSEL_ROW(0x01) \
> Why bother with defining GEN_XXSEL when its only used once?
> Surely just put the rows there.
>
> OTOH, this does suggest that we could do with a better way
> to decode the instructions, because this is ugly...
>
>
> r~
Yeah ... it isn't very pretty.  There was precedent for this (see, for 
example, rldcl).  And the decoding logic very much wants to use 
instruction bits 26:30 and 21:25 as opc2 and opc3 respectively. Perhaps 
I could inject a handler for opcode 60 that would handle the VSX map a 
little more gracefully.

Is your concern aesthetic?  Memory consumption?  And do you feel this is 
a showstopper or something that could be addressed later?