ZXpand Amusing Incompatibility

[gozzo]

Am I right in assuming that the overlay rom in the zxpand is based on the later 'corrected' version?? (I hope!)

[Moggy]

Whilst the xpand rom is the corrected later version, the "shoulders of Giants" rom would be ,in my opinion, a better alternative being slightly faster mathematically.
As for the issue one old rom hardware fix it was still slightly buggy and would give skewed results at times.

Moggy

[RWAP]

Hmm - thinking of the new forthcoming ZXpand (Iss 3) - I wonder whether it would be feasible to have a switchable EPROM, so the user could choose whether to use the original ZX81 ROM, or the Shoulders of Giants ROM (presumably there could be some software which will not work with the latter)

[angus]

Just for the record, my ancient Zeddy with the original klutzed Rom and no 'fix' works fine with ZXpand.

[gozzo]

has anyone thought of coming up with a 'integer basic' rom for the zx81 - as far as I see, the zx80 goes like the clappers compared to the zx81 with its floating point basic! But not like the zx80, using 2 bytes only -32767 to +32767, but using more, 4 or 5 posiibly, to give a larger range (similar to an unexpanded Acorn ATOM)
?

[Paul]

The zx81 powerbasic designer mathias is thinking about an integer version that has both floating point and integer variables with conversions. vice versa.
Powerbasic is a reset resident addon.
http://forum.tlienhard.com/phpBB3/viewt ... asic#p5566
There are various versions for different ram areas.
I don't know if he already started with implementation. This topic was heavily discussed on our meeting in march (in Germany) where he had public demos running. This is a very interesting piece of software giving loads of additional commands and still staying loadable on standard Zeddy's. (not executable of course).

[1024MAK]

Code: Select all

Bytes	Range			  from lowest	  Bin / Hex	  to Highest		Bin / Hex
1		256				 -128				 10000000	   127				 1111111
2		65536			  -32768			  8000			 32767			  7FFF
3		16777216		  -8388608			800000		  8388607			7FFFFF
4		4294967296		-2147483648		80000000		2147483647		7FFFFFFF
5		1099511627776	-549755813888	 8000000000	 549755813887	 7FFFFFFFFF

Does anyone need a five byte integer system?

Mark

[Paul]

Maybe for a loop that runs until doomsday?

[Paul]

I guess the powerbasic variables will be 2bytes. Lager numbers can still use float then.