[Coco] CPU speed in MIPS

[coco at yourdvd.net]

The fix for this is located in the unravelled series of books, probably
the super extended basic book, it simply puts the removed code back in.
I used to add it to all of my programs. It appeared in several other
places as well, but it would be easiest to find in the unravelled
series, which is more than likely where it originated,,,, -r

> -------- Original Message --------
> Subject: Re: [Coco] CPU speed in MIPS
> From: Joel Ewy <jcewy at swbell.net>
> Date: Thu, April 19, 2007 9:44 pm
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> 
> William Astle wrote: >> Diego Barizo wrote: >> >>> Surprisingly, the
> high speed poke turns a sluggish CoCo into a PC >>> killer (The T.1100
> laptop) >>> The poor rating on the Print test for the CoCo 3 is
> because I used one >>> of the hi-res text modes. >>> But anyway, the
> CoCo3 seems slower than a 2. Might be because the 3 is >>> always in
> "all RAM"? >>> > > That's actually easily explained. Between every
> statement, there is a > poll for the BREAK key. On the original color
> basic, that meant doing a > full poll of the keyboard between every
> statement. In newer versions, > POLCAT was patched to check if any key
> was down and if none were down at > all, it didn't bother polling the
> keyboard. The upshot of this is that > BASIC runs faster as long as no
> keys or joystick buttons are pressed. > > Unfortunately, a patch in
> the CoCo3 removed the check in POLCAT so that > the keyboard is
> scanned completely between every statement again. That > means that
> the system runs a bit slower than an equivalent CoCo2. > > IIRC,
> there's also a replacement to the command interpretation loop in >
> DECB 1.1 which does the same thing so you would think that DECB 1.1 >
> would solve the problem on the CoCo3. Unfortunately, the patching >
> routine in the CoCo3 recognizes DECB 1.1 and patches that routine out
> > too. Useful, eh? > > So, basically, the CoCo3 is running slower than
> the CoCo2 on plain basic > statements because of the BREAK check
> process is scanning the keyboard > whether a key is down or not. > > I
> think I've seen a POKE (or series of POKES?) that purports to fix
> this. I don't recall now where I found that. JCE -- Coco mailing list
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