Updated ZX81 ROM

[RWAP]

I have finished uploading a file based on the suggested improvements to the ZX81 ROM made by Thomas Bent. I have updated the listing changes so that they are based on Geoff Wearmouth’s incomplete disassembly of the ZX81 ROM – see http://www.wearmouth.demon.co.uk/zx81.htm, which itself takes account of Stephen Agate’s improved ZX81 ROM version – see http://homepages.nildram.co.uk/~agate/ROMDifference.htm

The instructions file has some issues highlighted in yellow, mainly due to the poor quality of the printout.

[XavSnap]

Hi,
I asually test the Rom with "Adventure A,B ,C ..." games.
It use a part of display rom codes (Pause codes!!!).
Is there any rom offset problèmes in this Rom ?
I will try it with Vb81 XuR...


Hoops...

Is there any binary files on the web???

[RWAP]

Alas there are no binary files as yet - I am not certain about some of the codes!!

[XavSnap]

Hi,

Somes of Zx81's rom change can hang emulators feature.
Vb81 classic patch the Rom to get keys and tape feature.
The Xur release short-cut the display routine 8-(
We had to test it...

[RWAP]

I presume you mean the changes which I have uploaded, which were suggested by Thomas Bent or do you mean all of the changes suggested by the disassembly on Geoff Wearmouth's pages?

If you have compiled the amended code, can you please confirm what the corrections are to the highlighted lines please and I will incorporate these into the original document.

[thewiz]

An idea that would be good in an updated ROM is to rearrange the system variables so that the largest continuous block of memory, not used by the interrupt routines or those used when loading a program, is available. This will give somewhere else to put M/C on a 1K machine.