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From: akcs.joehorn@hpcvbbs.UUCP (Joseph K. Horn)
Newsgroups: comp.sys.handhelds
Subject: Re: 28 Processor notes errata/question
Message-ID: <274ae32a:1193.1comp.sys.handhelds;1@hpcvbbs.UUCP>
Date: 21 Nov 90 20:40:07 GMT
References: <11962@life.ai.mit.edu>
Lines: 29

Jan Brittenson asked:

>   In Alonzo's HP28 Processor Notes, the section on the OUT
> instruction (in the table "by type") reads:
>
>
>   Copy OUT register to register A or C
>
>            800  OUT.S     C
>            801  OUT.X     C
>
>    Is 800 actually "OUT.X A" or should the description read
> "Copy register C to OUT register"?

Opcode 800 loads the least significant nib of OUT with the least
significant nib of C.  HP's mnemonic for this instruction is
OUT=CS, where "S" stands for "Single nib", I suppose; it cannot
stand for the S field, because OUT=CS copies nib 0, not nib F.

Opcode 801 loads all three nibs of OUT with the three low-order
nibs of C (not A), which is field X.  HP's mnemonic for this
instruction is OUT=C.

There is an A=IN instruction, but no OUT=A (at least in the HP 71
and HP 28).

This information is mere hearsay and not guaranteed blah blah.

--  Joseph K. Horn  --  (714) 858-0920  --  Peripheral Vision, Ltd.