Re: The Indexed Instruction Problem Solved!

From	John Levine <johnl@iecc.com>
Newsgroups	comp.arch
Subject	Re: The Indexed Instruction Problem Solved!
Date	2011-07-09 18:37 +0000
Organization	Taughannock Networks, Trumansburg NY
Message-ID	<iva763$22o3$1@gal.iecc.com> (permalink)
References	<b4ebeaa5-411f-4ee8-8a18-71a49e4e0ed3@glegroupsg2000goo.googlegroups.com> <d6lRp.57883$8G4.54572@newsfe17.iad> <iv5mig$1acn$1@gal.iecc.com> <d10Sp.23658$Mo3.2539@newsfe15.iad>

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>I guess they were trying to offload operations
>to memory due to the paucity of registers
>(at least Nova was register challenged:
>4 accumulator registers + PC, SP, FP).

The PDP-8 and 9 were single accumulator, so four registers
seemed pretty advanced, at least until you saw the 6 2/3 registers
on the -11.  (Two of the 8 registers were reserved as SP and PC.)

>If that is the case then I think the TI 9900 approach would be a
>better with all its registers in memory and an 'address of register
>bank' pointer register in the cpu.  Much cleaner and cheaper.

Slower, too, I would expect.  On the PDP-6 and KA10, the standard
confguration put the 16 registers in memory, and the flip-flop
registers were an option.  I don't think they ever sold a computer
without that option, though.

>Speaking of cheap: I saw a wiring diagram for one model of a Nova
>(back when computers came with such) and it had only a single 74181
>4-bit ALU.

Anyone have diagrams for the bit serial PDP-8/S?  Opinons varied on
whether the S stood for Serial or Slower than Sh*t, but it did take
90us to do a worst case ISZ instruction that used an indirect address
of an auto-increment location that turned to zero so the instruction
skipped, due to the three trips through the adder.

R's,
John

Thread

Re: The Indexed Instruction Problem Solved! MitchAlsup <MitchAlsup@aol.com> - 2011-07-06 14:12 -0700
  Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-06 15:48 -0700
  Re: The Indexed Instruction Problem Solved! EricP <ThatWouldBeTelling@thevillage.com> - 2011-07-06 20:36 -0400
  Re: The Indexed Instruction Problem Solved! "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-06 23:29 -0700
    Re: The Indexed Instruction Problem Solved! "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-06 23:31 -0700
      Re: The Indexed Instruction Problem Solved! "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-06 23:38 -0700
        Re: The Indexed Instruction Problem Solved! "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-06 23:39 -0700
          Re: The Indexed Instruction Problem Solved! timcaffrey@aol.com (Tim McCaffrey) - 2011-07-14 01:36 +0000
        Re: The Indexed Instruction Problem Solved! Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-07-07 08:12 -0700
        Re: The Indexed Instruction Problem Solved! EricP <ThatWouldBeTelling@thevillage.com> - 2011-07-07 12:24 -0400
          Re: The Indexed Instruction Problem Solved! John Levine <johnl@iecc.com> - 2011-07-08 01:29 +0000
            Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-07 18:53 -0700
              Re: The Indexed Instruction Problem Solved! John Levine <johnl@iecc.com> - 2011-07-08 02:17 +0000
            Re: The Indexed Instruction Problem Solved! EricP <ThatWouldBeTelling@thevillage.com> - 2011-07-09 13:15 -0400
              Re: The Indexed Instruction Problem Solved! John Levine <johnl@iecc.com> - 2011-07-09 18:37 +0000
                Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-09 11:53 -0700
                Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-09 11:55 -0700
              Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-09 11:49 -0700
              Re: The Indexed Instruction Problem Solved! Chris Jones <clj@panix.com> - 2011-07-09 16:21 -0400
        Re: The Indexed Instruction Problem Solved! Joe Chisolm <jchisolm6@earthlink.net> - 2011-07-07 13:19 -0500
          Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-07 12:11 -0700
          Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-07 12:13 -0700
            Re: The Indexed Instruction Problem Solved! jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-07 19:32 +0000
      Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-07 04:09 -0700
  Re: The Indexed Instruction Problem Solved! Brett Davis <ggtgp@yahoo.com> - 2011-07-12 18:31 -0500
    Re: The Indexed Instruction Problem Solved! "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-13 22:31 -0700
    Re: The Indexed Instruction Problem Solved! mac <acolvin@efunct.com> - 2011-07-17 15:31 +0000
      Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-17 09:50 -0700
        Re: The Indexed Instruction Problem Solved! Andrew Reilly <areilly---@bigpond.net.au> - 2011-07-17 23:26 +0000
          Re: The Indexed Instruction Problem Solved! Brett Davis <ggtgp@yahoo.com> - 2011-07-17 19:52 -0500
          Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-17 18:22 -0700
            Re: The Indexed Instruction Problem Solved! "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-17 21:33 -0700
              Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-18 06:34 -0700
                Re: The Indexed Instruction Problem Solved! Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-07-18 09:22 -0700
              Re: The Indexed Instruction Problem Solved! nmm1@cam.ac.uk - 2011-07-18 14:13 +0100
                Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-18 07:27 -0700
                Re: The Indexed Instruction Problem Solved! nmm1@cam.ac.uk - 2011-07-18 16:22 +0100
                Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-18 09:56 -0700
                Re: The Indexed Instruction Problem Solved! nmm1@cam.ac.uk - 2011-07-18 17:43 +0100
                Re: The Indexed Instruction Problem Solved! Quadibloc <jsavard@ecn.ab.ca> - 2011-07-18 14:58 -0700
                Re: The Indexed Instruction Problem Solved! nmm1@cam.ac.uk - 2011-07-19 07:22 +0100

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