Re: TIB: increment/decrement and skip

To: ti-basic@lists.ticalc.org
Subject: Re: TIB: increment/decrement and skip
From: Jody <jody1@alaska.net>
Date: Tue, 03 Feb 1998 15:42:15 +0000
References: <67185951.34d6ba34@aol.com> <19980203.160308.7639.0.UNIBOMER@juno.com>
Reply-To: ti-basic@lists.ticalc.org


Jared Ivey wrote:
> 
> On Tue, 3 Feb 1998 01:33:22 EST TGaArdvark@aol.com writes:
> >
> >> Are there any real use for the IS< and DS<
> >> functions?  I cannot figure out what situation
> >> would require them.  Any ideas?
> >
> >HAHA! I've been wondering this for years. I have
> >never used them or seen a program which used them.
> >I know what they do but prefer for or while loops.
> >Anyone else know what they could be used to do?
> 
> They're used to Increment the first parameter and skip the next
> instruction if it's greater than the second parameter, and to Decrement
> the first parameter and skip the next instruction if it's less than the
> second parameter.
> 
> The reason I sometimes use them is because they're faster than a for
> loop.  It has to do with the way it's interpreted into machine code.  If
> you know assembly, "inc a" is faster than "add a,1".
> 
> 6.7s 33b
> :ClLCD
> :For(X,1,100
> :Disp X
> :End
> 
> 9.5s 44b
> :ClLCD
> :1->X
> :Lbl A
> :Disp X
> :IS>(X,100
> :Goto A
> 
> Well, at least it was faster for something I did on the 85 a few years
> ago.  There is still one use for IS>(, the second parameter can be a
> variable, so you can conditionally check to see if an incremented
> variable is greater than another variable used in other calculations.  It
> does have it's usefulness, though I like For better.  You just have to
> determine the proper code for each individual program's need.
> 
> Sincerely,
> The Unibomer
> 
> Jared Ivey
> Unibomer@Juno.com
> http://www.geocities.com/SiliconValley/Vista/7342
> 
> "usenet: it's not an obsession.  it's just something I have to do ALL THE
> TIME" -- Meredith "gypsy" Tanner
> 
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Even if the second condition is variable, you can still use either 
While or Repeat. Both are fast, and, in my opinion, easier to use.

Jody Snider
jody1@alaska.net

References:

Re: TIB: TIB increment/decrement and skip

From: TGaArdvark@aol.com

Re: TIB: increment/decrement and skip

From: unibomer@juno.com (Jared Ivey)