Summer 1979, Issue 3

Page 6 of 26

Dear Mr.Cockshott,

Congratulations on finding the hidden bonus in the Z80. It is unfortunate that we can never be certain that every Z80 in the world has these instructions. Some might execute them unreliably.

There are 8 more hidden instructions which are prefixed by CB. These were found not to work as originally intended when the Z80 was built, so they were simply written out of the specification. See if you can find them and work out what they do wrong! Also, there may be some ED prefix instructions that have not yet been found. Good hunting.

The Editor.

Dear Sir,

I just had to write and congratulate you on Issue 2 of the INMC news. I enjoyed every page and every article and found the tips most invaluable to a striving amateur like myself. Your publication is a shining light in the NAS­COM wilderness. Please! Please! keep it up.

P.S. When I have mastered the art sufficiently to contribute – I will have a go!

Yours faithfully


Dear Mr.Lincoln,

What can we say except thank you. We will not be able to “keep it up” however, without some support from the vast membership. The four of use who make up the INMC committee wrote the last issue and this issue in their entirety and yet we all have full-time jobs. I am sure that it is not beyond each member’s scope to write just one short article and send it to us. If we can, then so can everyone else. We look forward to hearing from you when you have “mastered the art”.

Yours sincerely

The Editor,

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