|Re: HP-42S Lewis Processor Instruction Set|
Message #2 Posted by Reinhard Hawel on 14 Feb 2000, 6:21 p.m.,
in response to message #1 by José Manuel Pérez
Would be nice, if you'd post this article here
1) A 5 nibble address is almost certainly an absolute address. Please note, the addresses lie in the memory in the reverse direction.
If your address is "ABCDE" after loading, the register will contain "EDCBA"
That's the method, I would jump to such a pointer (if I were HP):
LC(5) Pointradr Load address of pointer
CD1EX swap into Data pointer 1
C=DAT1 A Load pointer
RSTK=C onto Return Stack
RETURN Jump there
(The CGI script for the forum filters my formatting spaces out, so this might get unreadable afterwards - grrrr) In the "newer" CPUs (after the 71B's CPU) there was a PC=C or PC=A command, so the last two commands could be substituted with:
PC=C Jump there
2) I guess you've found the "official" HP mnemonics. Gariepy's nemonics are not the official Mnemonics and the HP Guys didn't correspond about them in the past, because they didn't "understand" them. They were simply used to their own mnemonics. (And so am I)
If there are commands like A=A+A C or LCHEX ... or like the ones I used above then these are definitely the official mnemonics.