RE: [colorforth] Don't care areas in COLOR.COM ?

["howerd.oakford" <howerd.oakford@xxxxxxxxxxxx>]

Hoi Albert,

> 1. Non-zero's at the end of screen 53 (it starts with a lot of zero's)
> Typical 808080 08000 running for a dozen of bytes.
Block 53 is a shadow block for the serial LAN code, so its contents should
not affect anything.
> Is the content of screen 53 supposedly all zero?
Yes.

> 2. Unidentified objects between 4200 and screen 18.
IIRC the icons are 12k bytes from 6k upwards ( 0x3000 bytes from 0x1800 ).
In Chuck's original colorForth not all of the icons are used. In my version
I have added a full set of ASCII characters, plus I use the last 256 bytes
for the version info displayed by cfdos.com .
Changing this could affect the appearance of certain characters.

> 3. High addresses (>10,0000) in the tables of code addresses
> for Forth and Macro.
I would guess that they are not part of the tables. This could be compiled
code. This is the most likely cause of failure if you erased it...

Hope this helps.

Regards

Howerd


-----Original Message-----
From: Albert van der Horst [mailto:albert@xxxxxxxxxxxxxxxxxx]
Sent: 04 June 2005 15:28
To: colorforth@xxxxxxxxxxxxxxxxxx
Subject: [colorforth] Don't care areas in COLOR.COM ?


In looking at the original COLOR.COM I see the following

1. Non-zero's at the end of screen 53 (it starts with a lot of zero's)
Typical 808080 08000 running for a dozen of bytes.
2. Unidentified objects between 4200 and screen 18.
3. High addresses (>10,0000) in the tables of code addresses
for Forth and Macro.

Is the content of screen 53 supposedly all zero?
Do the icons run from 3000 to 4200 and not more?
Are the high addresses don't care because they are in a screened
off part of the table?

These (and a couple of noop's generated by assemblers to fill up
before an align) are the only areas in colorforth I can't identify.

Any help is appreciated.

(I guessed that COLOR.COM would still run if all of the above is
zeroed. But Ray has tried this and it is not so.)

Groetjes Albert

--
Albert van der Horst,Oranjestr 8,3511 RA UTRECHT,THE NETHERLANDS
Economic growth -- like all pyramid schemes -- ultimately falters.
albert@xxxxxxxxxxxxxxxxxx http://home.hccnet.nl/a.w.m.van.der.horst

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