Re: New Vax - future directions :-)

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> My problem with CLRQ R0 is that is **necessarily** behaves radically differe$

Depends on how you look at it.

CLRB R0: clears the lowest 8 bits starting at the low end of R0.
CLRW R0: clears the lowest 16 bits starting at the low end of R0.
CLRL R0: clears the lowest 32 bits starting at the low end of R0.
CLRQ R0: clears the lowest 64 bits starting at the low end of R0.
CLRO R0: clears the lowest 128 bits starting at the low end of R0.

The only thing that's at all notable about CLRQ and CLRO is that,
because they affect a datum larger than a register, they necessarily
affect more than one register.

Yes, CLRO (and CLRQ, on VAX-32) affect more than one register, because
they affect more than one register holds.  And CLRB and CLRW (and
presumably CLRL on VAX-64) affect less than one register, because they
affect less than one register holds - so?

Look at the register file as a bitstring and CLRx Rn affects an x-sized
string of those bits, starting at the bottom end of Rn.  Where the
register boundaries happen to fall doesn't have much to do with it.

That's my take on the countering interpretation, at least.

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