42S local label caching

[Sylvain Cote]

Dave,

(11-11-2019 06:56 PM)Dave Britten Wrote:  So GTO 10, for example, is a 2-byte instruction on my 42S. That would mean one byte encodes the GTO 10, and a second byte is reserved to store a +/-128-byte offset.

That seems to be the case for the HP-42S, as for the HP-41C the internal structures are different.
Look at The HP-41 SYNTHETIC Quick Reference Guide from Jeremy Smith, page 39 available at TOS.

(11-11-2019 06:56 PM)Dave Britten Wrote:  And for GTO 99, which is 3 bytes, 13 bits could store +/-4,096, and the remaining 11 bits encode the GTO 99 itself.
Do I have that right? XEQ instructions are always 3 bytes, so I'm not exactly sure how those are formed.

I did not have the time last night to find the HP-42S internal structure information, at this moment I am as blind as you on this subject.

(11-11-2019 06:56 PM)Dave Britten Wrote:  Will local GTO/XEQ inside "OTHER" be cached in the same way? I'm assuming yes since the offsets are stored directly in the GTO/XEQ instructions.

You are correct.

(11-11-2019 06:56 PM)Dave Britten Wrote:  

(11-11-2019 06:18 PM)Sylvain Cote Wrote:  Ref.: Synthetic Programming on the HP-41C, by W.C Wickes, pages 16 & 17

That's the one on the museum DVD/document set, right?

Yes, it is part of the Museum Document Sets (8.0) and also available at TOS.

Sylvain