Recall Arithmetic: The haves and have-nots

[PANAMATIK]

(05-24-2015 08:52 PM)Dieter Wrote:  .... on the 34C storage arithmetics is limited to registers 0...9, while it is not available on registers ,0...,9 and the I register.....

Today I was able to add the HP-34C opcode table to my ProgramCodes.pdf document.

You can see that the HP-34C uses up all 256 possible opcodes except one for coding its program steps. The engineers choose carefully which are the most important functions. The SOLVE and Integral function uses only 6 of 12 labels. And as already mentioned, storage arithmetic can be done only with the ten primary registers.

The most interesting part is to see, that f SCI 8,9 and f ENG 8,9 are not programmable. Only SCI 0-7 and ENG 0-7 are present, because the table would have overflown. If you try to program one of these display formats, it will be replaced by SCI 7 ENG 7, which is also mentioned in the manual. The more important f FIX 0-9 however is fully programmable.

Even with the reduced registers 0-9, storage arithmetic uses 44 of 255 opcodes. Recall arithmetic would have needed another 44 opcodes.

Due to this space limitation, the HP-34C was probably the last and ultimate model, which used the one byte program step coding. I'm not sure whether the voyager models had already two bytes. Does anybody know?

Bernhard