Hey folks!

I have a question about something i'm trying to write in D.  I have two arrays
of 144 bits, and I
need to XOR them, and store the result in yet a third array of 144 bits.  Any
suggestions on how to
do this?  Do the bit arrays need to be dynamic or static?  I'm just a tad
confused!

Thanks,
Owen Anderson

In article <bk7u0c$1tb9$1@digitaldaemon.com>, resistor@mac.com says...
>
>Hey folks!
>
>I have a question about something i'm trying to write in D.  I have two arrays
>of 144 bits, and I
>need to XOR them, and store the result in yet a third array of 144 bits.  Any
>suggestions on how to
>do this?  Do the bit arrays need to be dynamic or static?  I'm just a tad
>confused!
>
>Thanks,
>Owen Anderson
>
>

Uhhh... Use != to xor bits, and use a for statement to walk the array?

John Boucher
The King had Humpty pushed

In article <bk7vhl$23mn$1@digitaldaemon.com>, John Boucher says...
>
>In article <bk7u0c$1tb9$1@digitaldaemon.com>, resistor@mac.com says...
>>
>>Hey folks!
>>
>>I have a question about something i'm trying to write in D.  I have two arrays
>>of 144 bits, and I
>>need to XOR them, and store the result in yet a third array of 144 bits.  Any
>>suggestions on how to
>>do this?  Do the bit arrays need to be dynamic or static?  I'm just a tad
>>confused!
>>
>>Thanks,
>>Owen Anderson
>>
>>
>
>Uhhh... Use != to xor bits, and use a for statement to walk the array?
>
>John Boucher
>The King had Humpty pushed

Is it not possible to use an array operator to do all of them at once?  And
also, isn't ^ the XOR
operator?  That's what the documentation says, but I suppose it could be wrong.

Owen Anderson

<resistor@mac.com> wrote in message news:bk81nb$2bh3$1@digitaldaemon.com...
> In article <bk7vhl$23mn$1@digitaldaemon.com>, John Boucher says...
> >
> >In article <bk7u0c$1tb9$1@digitaldaemon.com>, resistor@mac.com says...
> >>
> >>Hey folks!
> >>
> >>I have a question about something i'm trying to write in D.  I have two
arrays
> >>of 144 bits, and I
> >>need to XOR them, and store the result in yet a third array of 144 bits.
Any
> >>suggestions on how to
> >>do this?  Do the bit arrays need to be dynamic or static?  I'm just a
tad
> >>confused!
> >>
> >>Thanks,
> >>Owen Anderson
> >>
> >>
> >
> >Uhhh... Use != to xor bits, and use a for statement to walk the array?
> >
> >John Boucher
> >The King had Humpty pushed
>
> Is it not possible to use an array operator to do all of them at once?
And
> also, isn't ^ the XOR
> operator?  That's what the documentation says, but I suppose it could be
wrong.
>
> Owen Anderson

There was a plan once upon a time to implement operations on entire arrays at once, and if that ever gets implemented you'll be able to do something like this:

bit[144] a, b, c;
a[] = b[] ^ c[];  // could use != instead of ^... ^ returns each bit, !=
only returns one bit and only acts like an xor if used on single bits

Sean

Isnt there some special CPU instruction set that ill apply an operation to an array or matrix or something, vectorizing compilers or something like that ?

Charles

"Sean L. Palmer" <palmer.sean@verizon.net> wrote in message news:bka32e$2km1$1@digitaldaemon.com...
> <resistor@mac.com> wrote in message
news:bk81nb$2bh3$1@digitaldaemon.com...
> > In article <bk7vhl$23mn$1@digitaldaemon.com>, John Boucher says...
> > >
> > >In article <bk7u0c$1tb9$1@digitaldaemon.com>, resistor@mac.com says...
> > >>
> > >>Hey folks!
> > >>
> > >>I have a question about something i'm trying to write in D.  I have
two
> arrays
> > >>of 144 bits, and I
> > >>need to XOR them, and store the result in yet a third array of 144
bits.
> Any
> > >>suggestions on how to
> > >>do this?  Do the bit arrays need to be dynamic or static?  I'm just a
> tad
> > >>confused!
> > >>
> > >>Thanks,
> > >>Owen Anderson
> > >>
> > >>
> > >
> > >Uhhh... Use != to xor bits, and use a for statement to walk the array?
> > >
> > >John Boucher
> > >The King had Humpty pushed
> >
> > Is it not possible to use an array operator to do all of them at once?
> And
> > also, isn't ^ the XOR
> > operator?  That's what the documentation says, but I suppose it could be
> wrong.
> >
> > Owen Anderson
>
> There was a plan once upon a time to implement operations on entire arrays at once, and if that ever gets implemented you'll be able to do something like this:
>
> bit[144] a, b, c;
> a[] = b[] ^ c[];  // could use != instead of ^... ^ returns each bit, !=
> only returns one bit and only acts like an xor if used on single bits
>
> Sean
>
>
>
>

There certainly is.  It is usually a bit more limited than the normal instruction set but enough to get most jobs done, with a quickness.  ;)

My coworker just wrote a function for PS2 that processes 16 triangle bounding boxes at the same time, using a few min/max/compare instructions.

It would be nice if in D you could express this as simply as:

typedef byte[16] b16;
extern b16 a,b,c;
b16 res = a[] + b[] < c[] && a[] - b[] > c[];

Sean

"Charles Sanders" <sanders-consulting@comcast.net> wrote in message news:bkaj99$aq1$1@digitaldaemon.com...
> Isnt there some special CPU instruction set that ill apply an operation to an array or matrix or something, vectorizing compilers or something like that ?
>
> Charles
>
> "Sean L. Palmer" <palmer.sean@verizon.net> wrote in message news:bka32e$2km1$1@digitaldaemon.com...
> > There was a plan once upon a time to implement operations on entire
arrays
> > at once, and if that ever gets implemented you'll be able to do
something
> > like this:
> >
> > bit[144] a, b, c;
> > a[] = b[] ^ c[];  // could use != instead of ^... ^ returns each bit, !=
> > only returns one bit and only acts like an xor if used on single bits
> >
> > Sean