Re: Re: Re: [f-cpu] GCC 3.1 for F-CPU port

[whygee@club-internet.fr]

hi,

>De: "Antoine"
>
>>>In my opinion, an integer (or a pointer) wider than 64 bits
>>> really has no point. Such widths should be reserved for SIMD.
>>
>> why "reserved" ?
>
>I meant e.g. 128-bit registers could be used for 2*64, 4*32,
>8*16 or 16*8, but not for a single 128-bit integer/pointer.

oh, _that_ old debate ...

but then why would someone be kept from using a "whole"
register for holding a bitmask (for video, or whatever)
or even an IPv6 address, or things like that ?
integers are not the only data types out there ...

my point of view is that a register doesn't necessarily
contains an "integer". Usually, in C, one has to cover
bitmask and such under the name of "integer". but i consider
that as a limitation .... What if i'm dealing with a bitfield
of many bits ? It's SIMD in a sense, but if there are 100 bits,
then the 'integer' approach does not work nicely.
However if you think in term of "register" it's ok with F-CPU.

This is why the size postfix would contain .128 and so on.
This would trap if the CPU doesn't implement the
corresponding operations, but at least ROP2 can do it ;-)

>But someone else had a point : 128-bit floats could be useful ;)

well, they are quite large and not much used, or useful
in practice .... unless someone wants to do quantic
chromodynamics or something like that _and_ comes with the
adapted unit ;-) (lazy me)

YG

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