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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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