horrible C indexing

"robert bristow-johnson" <rbj@audioimagination.com> wrote in 
message 
news:1144041555.371128.119790@z34g2000cwc.googlegroups.com...
>
> Andrew Reilly wrote:
>>
>> double buf[10];
>> base1_routine(buf - 1);   /* or base1_routine(&buf[-1]); 
>> equivalent */
>>
>
> so, Andrew, are they saying that buf-1 is not guaranteed 
> to be an
> address that you could form a pointer with and index off 
> of?
>

I wonder what would happen to (buf-1)+1 in a weird 
environment like the overlapped, segmented memory model of 
the 8086/80286 if buf were mapped to the zero-th address in 
a segment.

> double buf[10];
> base1_routine(buf - 1)
>
> void base1_routine(double *a)
> {
>   int i;
>   for (i = 1; i <= 10; i++)
>   {
>     a++;
>     *a = foo(i, a);
>   }
> }


C doesn't assume a flat addressing model for physical 
memory.  In fact, it doesn't assume much of anything about 
the physical machine.  In order to make the above code 
fragment work, 'a' would have to be maintained as a pointer 
to a flat address space and the compiler would have to emit 
a bunch of code to convert the pointer into a segmented 
address.  To be sure, some C compilers offered this as an 
option (sometimes called the "Large Model"), but the user 
paid a heavy price in performance for using it.

robert bristow-johnson wrote:
> :-)
> 
> (hey guyz, pleeeze crosspost these to c.s-s.m.  otherwize it's just our
> private pleasure.)

Naw, r, if there's one thing I learned from the original thread years 
ago, it's that Clive and the devoted Matminions he's fleeced ain't got 
no sense of humor. ;-)

=g2
_____________________________________________________________________

Grant R. Griffin
Publisher of dspGuru                           http://www.dspguru.com
Iowegian International Corporation            http://www.iowegian.com
See http://www.iowegian.com/img/contact.gif for e-mail address

Grant Griffin wrote:
> robert bristow-johnson wrote:
> > :-)
> >
> > (hey guyz, pleeeze crosspost these to c.s-s.m .  otherwize it's just our
> > private pleasure.)
>
> Naw, r, if there's one thing I learned from the original thread years
> ago, it's that Clive and the devoted Matminions he's fleeced ain't got
> no sense of humor. ;-)

perhaps or not.  i might expect *Cleve* (with two e's) to take it more
humorously if we at least refrain from misspelling his first name.

Cleve, i got over a half decade ago hoping to positively influence you
about this.  i hope you got at least a little self-depricating kick out
of Grant's and Al's pokes.  it's good for all of us.

r b-j

"robert bristow-johnson" <rbj@audioimagination.com> wrote in 
news:1144081152.417034.11310@e56g2000cwe.googlegroups.com:

> Cleve, i got over a half decade ago hoping to positively influence you
> about this.  i hope you got at least a little 
> ***self-depricating*** (emphasis added) kick out
> of Grant's and Al's pokes.  it's good for all of us.
> 


I should have known that a bunch of guys who can't understand a ones-based 
index system would spell phonetically.  Were you overwhelmed when Crayola 
made the jump to 96-color boxes?


-- 
Scott
Reverse name to reply

Scott Seidman <namdiesttocs@mindspring.com> wrote in
news:Xns979A7FA382803scottseidmanmindspri@130.133.1.4: 

> "robert bristow-johnson" <rbj@audioimagination.com> wrote in 
> news:1144081152.417034.11310@e56g2000cwe.googlegroups.com:
> 
>> Cleve, i got over a half decade ago hoping to positively influence
>> you about this.  i hope you got at least a little 
>> ***self-depricating*** (emphasis added) kick out
>> of Grant's and Al's pokes.  it's good for all of us.
>> 
> 
> 
> I should have known that a bunch of guys who can't understand a
> ones-based index system would spell phonetically.  Were you
> overwhelmed when Crayola made the jump to 96-color boxes?
> 
> 

I hate misspelling peoples names. I apologize. Since I can't spell, I guess 
it must prove that I really have an enigneering education.

-- 
Al Clark
Danville Signal Processing, Inc.
--------------------------------------------------------------------
Purveyors of Fine DSP Hardware and other Cool Stuff
Available at http://www.danvillesignal.com

Al Clark <dsp@danvillesignal.com> wrote in
news:Xns979A7C2CA8D8Eaclarkdanvillesignal@66.133.129.71: 

> Scott Seidman <namdiesttocs@mindspring.com> wrote in
> news:Xns979A7FA382803scottseidmanmindspri@130.133.1.4: 
> 
>> "robert bristow-johnson" <rbj@audioimagination.com> wrote in 
>> news:1144081152.417034.11310@e56g2000cwe.googlegroups.com:
>> 
>>> Cleve, i got over a half decade ago hoping to positively influence
>>> you about this.  i hope you got at least a little 
>>> ***self-depricating*** (emphasis added) kick out
>>> of Grant's and Al's pokes.  it's good for all of us.
>>> 
>> 
>> 
>> I should have known that a bunch of guys who can't understand a
>> ones-based index system would spell phonetically.  Were you
>> overwhelmed when Crayola made the jump to 96-color boxes?
>> 
>> 
> 
> I hate misspelling peoples names. I apologize. Since I can't spell, I
> guess it must prove that I really have an enigneering education.
> 

I was talking about "depricating", actually, and found the misspelling in 
the post correcting a misspelling to be somewhat funny. 

I took the opportunity to see if we can all enjoy the self-deprecating 
kick.


-- 
Scott
Reverse name to reply

Scott Seidman wrote:
> Al Clark <dsp@danvillesignal.com> wrote in
> news:Xns979A7C2CA8D8Eaclarkdanvillesignal@66.133.129.71:
>
> > Scott Seidman <namdiesttocs@mindspring.com> wrote in
> > news:Xns979A7FA382803scottseidmanmindspri@130.133.1.4:
> >
> >> "robert bristow-johnson" <rbj@audioimagination.com> wrote in
> >> news:1144081152.417034.11310@e56g2000cwe.googlegroups.com:
> >>
> >>> Cleve, i got over a half decade ago hoping to positively influence
> >>> you about this.  i hope you got at least a little
> >>> ***self-depricating*** (emphasis added) kick out
> >>> of Grant's and Al's pokes.  it's good for all of us.
> >>>
> >>
> >>
> >> I should have known that a bunch of guys who can't understand a
> >> ones-based index system would spell phonetically.  Were you
> >> overwhelmed when Crayola made the jump to 96-color boxes?
> >>
> >>
> >
> > I hate misspelling peoples names. I apologize. Since I can't spell, I
> > guess it must prove that I really have an enigneering education.
> >
>
> I was talking about "depricating", actually, and found the misspelling in
> the post correcting a misspelling to be somewhat funny.
>
> I took the opportunity to see if we can all enjoy the self-deprecating
> kick.

i'm happy with it.  after winning the MATLAB indexing base issue, we'll
take on the written english language to make it phonetic.  maybe get
Bill Gates involoved (we'll add "depricating" to the spell check
dictionary and then get it added to Webster a la the Dilbert cartoon).

"use to be i cudn't even spel enjinear, now i are one."

r b-j

robert bristow-johnson wrote:
> ... after winning the MATLAB indexing base issue...

Cool - what did you win?

spasmous wrote:
> robert bristow-johnson wrote:
> > ... after winning the MATLAB indexing base issue...
>
> Cool - what did you win?

well, we haven't won *yet*, but since truth and justice is on our side
and since truth and justice always wins (eventually), well then, it's
just a matter of time.  and when that time comes, we'll take on bigger
foes.

r b-j

robert bristow-johnson wrote:
> Grant Griffin wrote:
>> robert bristow-johnson wrote:
>>> :-)
>>>
>>> (hey guyz, pleeeze crosspost these to c.s-s.m .  otherwize it's just our
>>> private pleasure.)
>> Naw, r, if there's one thing I learned from the original thread years
>> ago, it's that Clive and the devoted Matminions he's fleeced ain't got
>> no sense of humor. ;-)
> 
> perhaps or not.  i might expect *Cleve* (with two e's) to take it more
> humorously if we at least refrain from misspelling his first name.

Actually, I had thought that Al's fine molarpropism could only add to 
the humor--especially on April 0th.  So I perpetuated it, not realizing 
that it could cause any toothaches. ;-)

=g2
_____________________________________________________________________

Grant R. Griffin
Publisher of dspGuru                           http://www.dspguru.com
Iowegian International Corporation            http://www.iowegian.com
See http://www.iowegian.com/img/contact.gif for e-mail address