From: grog@lemis.com (Greg 'groggy' Lehey)
Subject: [TUHS] PDP-8 (was: 2.11BSD cross compiler)
Date: Thu, 30 Sep 2010 14:22:29 +1000 [thread overview]
Message-ID: <20100930042229.GA66070@dereel.lemis.com> (raw)
In-Reply-To: <AANLkTin53c5N3wGpPfi5DQ1WdrqtV5+ENmSVSoiZwFXu@mail.gmail.com>
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On Tuesday, 28 September 2010 at 22:59:22 -0400, John Cowan wrote:
> On Tue, Sep 28, 2010 at 10:38 PM, Larry McVoy <lm at bitmover.com> wrote:
>
>> Color me old school. I like MIPS, I worked at SGI (got married to
>> an old school MIPS gal) but PDP-11 is so frigging intuitive. How
>> can you not understand that instruction set? If you can't, well,
>> sorry, not so much in my book. It's like a stripped down C.
>
> Yeah. I used it on and off, but my serious assembler programming
> was on the PDP-8. Now *that* was seriously small, but you had to
> know the tricks, like how to find out the absolute address of the
> 128-word memory page following the one you are on when writing PIC
> code for OS/8 device drivers, or how to microprogram the operate
> instructions get interesting constants into the AC.
That was my first machine too (well, a PDP-12, which was really a
hybrid PDP-8/LINC-8, but I only used the PDP-8 instructions). That
was a nice, compact instruction set. It has the great advantage that
I can still remember just about every instruction today. Remember the
autoincrement registers? Even in those days they looked like a
kludge, but they helped a lot.
>> Come on - has anyone ever seen a better instruction set? More
>> complicated, yeah, holy moly, yeah. But cleaner? We owe DEC
>> for that one.
>
> I remember how appalled I was when I saw the VAX instruction set.
> Luckily, it didn't matter: I never did assembler again. Still,
> trying to make people think in octal at this late date seems
> unnecessary.
It's funny how long octal clung on. It should have gone away with 8
bit bytes. But somehow I still have a soft spot for octal, and
numbers like 7778 still look wrong.
>> Personally, I like anyone who can do any assembler. One of my interview
>> questions is "have you written swtch?"
>>
>> If you don't get the question you are not an OS person,
>> if you are, of course you get it.
Hmm. Am I expected to understand this? Seriously, I don't know how
many people really wrote anything like swtch ().
Greg
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next prev parent reply other threads:[~2010-09-30 4:22 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-28 5:54 [TUHS] 2.11BSD cross compiler Nick Downing
2010-09-29 0:24 ` Tim Newsham
2010-09-29 0:51 ` Larry McVoy
2010-09-29 2:14 ` John Cowan
2010-09-29 2:38 ` Larry McVoy
2010-09-29 2:59 ` John Cowan
2010-09-29 3:44 ` Larry McVoy
2010-09-30 4:22 ` Greg 'groggy' Lehey [this message]
2010-09-30 4:53 ` [TUHS] PDP-8 (was: 2.11BSD cross compiler) John Cowan
2010-09-30 13:50 ` Larry McVoy
2010-10-02 3:46 ` Greg 'groggy' Lehey
2010-10-02 21:03 ` Larry McVoy
2010-10-02 21:39 ` [TUHS] PDP-8 M. Warner Losh
2010-10-02 10:06 ` [TUHS] PDP-8 (was: 2.11BSD cross compiler) Wolfgang Helbig
2010-09-29 3:14 ` [TUHS] 2.11BSD cross compiler M. Warner Losh
2010-09-29 3:17 ` Steve Nickolas
2010-09-29 3:55 ` Larry McVoy
2010-09-29 4:34 ` [TUHS] 6502 and swtch, was " Warren Toomey
2010-09-29 5:13 ` Steve Nickolas
2010-09-30 17:49 ` Tim Newsham
2010-09-29 20:54 ` [TUHS] " Peter Jeremy
2010-09-29 21:34 ` Larry McVoy
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