At 11:03 PM 9/8/2001 -0500, Brian Wheeler wrote:
>On Sat, 2001-09-08 at 22:24, Uri Guttman wrote:
> > >>>>> "BW" == Brian Wheeler <[EMAIL PROTECTED]> writes:
>Looking at the opcodes as presented in the PDD, they're hauntingly like
>the alpha codes (maybe Dan's favorite isn't the vax, but the alpha :)
I made one abortive foray into Alpha assembly. (The RC5 core, FWIW) Finding
details on the calling conventions and translating from Alpha NT format to
Alpha VMS format put a quick halt to that. Too much trouble for another
500kk/sec. :)
>If I hadn't let my hobbyist licenses expire on my vms/alpha machine, I'd
>check it too...
So go renew! It's easy...
> > which reminds
> > me, is there going to be a simple language way to get the word size
> > (other than %Config)?
There'll be some way to get info about the environment. I haven't gotten
there yet, though. (A set of status opcodes, basically)
> Well, what
>if a PMC or Numeric registers are passed to rol, rol, shr, shl? What
>would be the size then? We could disallow them since they really don't
>make sense...or do they?
Sure they do. Rotating bitvectors makes sense in some contexts, and
rotating PMCs that hold integers certainly do.
> Is the VM going go have a fixed size register
>set regardless of platform?
Number yes. Number of bits, no.
> If not, then the shift will behave
>differently on each platform the bytecode is run...and that's bad,
>especially if someone (cleverly) decides that a "SHL I0,I0,32" clears
>the register.
"Oh, that's clever!" are the three most dangerous words in the english
language. :)
Clever like that will get you bitten, and deservedly so, since "clear I0"
or "set I0, 0" is a darned sight more straightforward and faster.
>Honestly I pulled the mneumonics from the x86 set, though the ROL/ROR
>ops are the same as m68k.
Grabbing mnemonics from other folks assembly set is a reasonable thing, and
I'm OK with that. (There's no reason we can't have a short and long form,
but I don't know that I want to go that far right now)
Dan
--------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
[EMAIL PROTECTED] have teddy bears and even
teddy bears get drunk
