Xref: utzoo comp.misc:2966 comp.arch:5887
Path: utzoo!utgpu!attcan!uunet!husc6!m2c!applix!scott
From: scott@applix.UUCP (Scott Evernden)
Newsgroups: comp.misc,comp.arch
Subject: Re: History of PCs (also kind of long)
Keywords: history, pc, workstation
Message-ID: <758@applix.UUCP>
Date: 4 Aug 88 01:38:39 GMT
References: <5946@venera.isi.edu> <5458@ecsvax.uncecs.edu> <1876@looking.UUCP> <753@applix.UUCP> <1193@ficc.UUCP>
Reply-To: scott@applix.UUCP (Scott Evernden)
Organization: APPLiX Inc., Westboro MA
Lines: 23

In article <1193@ficc.UUCP> karl@ficc.UUCP (karl lehenbauer#) writes:
>As I recall, the RCA 1802 has eight 16-bit registers. 

No, there really were 16 16-bit registers.

>with its 8-bit accumulator, no multiply or divide instructions and no 
>subroutine call, it was kind of hosed.

Well, actually there were several subroutine call mechanisms to choose
from (at least 3)- from a simple SEP (set program counter) to the somewhat
involved SCRT (standard-call-and-return-technique).  Multiply/divide
was unavailable on _any_ micro in '77 or so (even the Z80).  I would say
that the 1802's big lack was in the area of addressing modes.  I'm not
sure I would agree it was 'hosed'.

>... RCA 
>later came out with an 1804 which, as I understand it (I never saw the part), 
>fixed some of the problems with the chip, but it didn't catch on as it 
>wasn't pin compatible.

The 1804 was merely an 1802 with 2k mask ROM, 64 bytes RAM, and a counter.

-scott