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Re: Rep:Re: Rep:Re: [f-cpu] signed cmpl



On Wed, 18 Dec 2002 12:07:32 +0100 (CET)
devik <devik@cdi.cz> wrote:

> > Sorry, I misunderstood. But on the other hand, 6 bits aren't much
> > for most purposes - you would have to `loadcons*' more often...
> >
> > >>>Only our gcc expert could answer. So, does 32 to -32 number (or 0
> > >to
> > 64) immediat instruction could cover most immediat instructions used
> > by gcc ?
> > nicO
> 
> Because I test majority of things with vsprintf.c from linux kernel
> just now it is not too objective. There is 275 immediates used in the
> file. Here is usage of constant NOT IN -32...31 range:
>      13 addi
>      21 andi
>       3 cmplei
>       1 cmplesi
>       2 ori
>      33 xor.ori
> 
> and these are IN range:
>     140 addi
>      23 andi
>       1 cmplei
>      13 cmplesi
>       3 cmplsi
>       4 nxor.andi
>       7 ori
>       4 shiftli
>       7 xor.ori
> 
> So that 202 insns ARE in 6bit range but these was constants 1 and -1
> often (addi) - I didn't implemented INC/DEC yet. There was 82 of such.
> As conclusion from 275 immediates 120 (202-82) can be coded into
> 6 bits.

And from that, how much can't use the actual 8 bits version (because 2
flag bitsdisappear ?)

nicO

> devik
> 
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