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What is the absolute smallest instruction set do you need to make aworking computer?



 
 
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  #1  
Old September 21st 19, 11:45 PM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
Yousuf Khan[_2_]
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Default What is the absolute smallest instruction set do you need to make aworking computer?

What's your guess? 100 instructions? 50 instructions? 10? Would you
believe just 1 instruction!? And that instruction is implied, you don't
even need an opcode for that! And you're not going to believe what that
one instruction is either! This video explains how it's possible.

https://youtu.be/jRZDnetjGuo

Yousuf Khan
  #2  
Old September 22nd 19, 01:49 AM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
Roger Blake[_2_]
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Posts: 24
Default What is the absolute smallest instruction set do you need tomake a working computer?

On 2019-09-21, Yousuf Khan wrote:
What's your guess? 100 instructions? 50 instructions? 10? Would you
believe just 1 instruction!? And that instruction is implied, you don't
even need an opcode for that! And you're not going to believe what that
one instruction is either! This video explains how it's possible.

https://youtu.be/jRZDnetjGuo


Interesting. In terms of commercially-successful CPUs the most minimal
I've worked with was the DEC PDP-8, which had 8 instructions (3-bit opcode).
However, one of those (OPR) permitted the programmer to combine several
operations into one instruction cycle by setting the appropriate bits.

The PDP-8 was a 12-bit word-oriented machine sold from 1965-1979. Early
models used discrete transistors, the last models were CMOS microprocessors.
There was also a serial model that operated on one bit at a time - slow!!
No stack was employed - subroutines worked via the caller writing the
return address into the first word of the called routine. Fun times!

--
-----------------------------------------------------------------------------
Roger Blake (Posts from Google Groups killfiled due to excess spam.)

NSA sedition and treason -- http://www.DeathToNSAthugs.com
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  #3  
Old September 22nd 19, 02:21 AM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
Arlen Holder
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Default What is the absolute smallest instruction set do you need to make a working computer?

On Sun, 22 Sep 2019 00:49:48 -0000 (UTC), Roger Blake wrote:

Interesting. In terms of commercially-successful CPUs the most minimal
I've worked with was the DEC PDP-8, which had 8 instructions (3-bit opcode).


A nand gate can implement all Boolean operations, can't it?

  #4  
Old September 22nd 19, 05:46 AM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
Yousuf Khan[_2_]
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Posts: 1,296
Default What is the absolute smallest instruction set do you need to makea working computer?

On 9/21/2019 9:21 PM, Arlen Holder wrote:
On Sun, 22 Sep 2019 00:49:48 -0000 (UTC), Roger Blake wrote:

Interesting. In terms of commercially-successful CPUs the most minimal
I've worked with was the DEC PDP-8, which had 8 instructions (3-bit opcode).


A nand gate can implement all Boolean operations, can't it?


And so the answer is, the only instruction you need is a Subtract
instruction! A special subtract instruction that branches only when the
result is less than or equal to zero. The video explains how that works.

Yousuf Khan
  #5  
Old September 22nd 19, 05:04 AM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
Jeff Barnett
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Posts: 6
Default What is the absolute smallest instruction set do you need to makea working computer?

Yousuf Khan wrote on 9/21/2019 10:46 PM:
On 9/21/2019 9:21 PM, Arlen Holder wrote:
On Sun, 22 Sep 2019 00:49:48 -0000 (UTC), Roger Blake wrote:

Interesting. In terms of commercially-successful CPUs the most minimal
I've worked with was the DEC PDP-8, which had 8 instructions (3-bit
opcode).


A nand gate can implement all Boolean operations, can't it?


And so the answer is, the only instruction you need is a Subtract
instruction! A special subtract instruction that branches only when the
result is less than or equal to zero. The video explains how that works.


I haven't looked at the video but (trying to remember from the 1960s)
you need 2 registers and places to branch on either crossing 0.
Essentially one register is the right half and the other the left half
of the "tape" and you are working with 2 characters, etc., etc.. etc.
--
Jeff Barnett
  #6  
Old September 22nd 19, 06:00 AM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
Yousuf Khan[_2_]
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Posts: 1,296
Default What is the absolute smallest instruction set do you need to makea working computer?

On 9/22/2019 12:04 AM, Jeff Barnett wrote:
I haven't looked at the video but (trying to remember from the 1960s)
you need 2 registers and places to branch on either crossing 0.
Essentially one register is the right half and the other the left half
of the "tape" and you are working with 2 characters, etc., etc.. etc.


This particular computer doesn't have any registers, it works directly
on memory. Now obviously in the background, the real chip might have
virtual registers that it uses as a buffer area, but that's completely
out of the control of the instruction set itself.
  #7  
Old September 22nd 19, 09:07 PM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
J. P. Gilliver (John)[_3_]
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Posts: 24
Default What is the absolute smallest instruction set do you need to make a working computer?

In message , Roger Blake
writes:
On 2019-09-21, Yousuf Khan wrote:
What's your guess? 100 instructions? 50 instructions? 10? Would you
believe just 1 instruction!? And that instruction is implied, you don't
even need an opcode for that! And you're not going to believe what that
one instruction is either! This video explains how it's possible.

https://youtu.be/jRZDnetjGuo


Interesting. In terms of commercially-successful CPUs the most minimal
I've worked with was the DEC PDP-8, which had 8 instructions (3-bit opcode).
However, one of those (OPR) permitted the programmer to combine several
operations into one instruction cycle by setting the appropriate bits.


The first computer I learnt on had 8 instructions (3 bit opcode); it was
a "computer" by Mr. Parr's definition of having a conditional jump among
its op.s [as opposed to a programmable calculator - common at the time,
1970s, which didn't], where the decision was based on the result of (in
this case) previous instructions. (The one-opcode answer given above
qualifies, as it is subtract-and-jump-if.)

The PDP-8 was a 12-bit word-oriented machine sold from 1965-1979. Early
models used discrete transistors, the last models were CMOS microprocessors.
There was also a serial model that operated on one bit at a time - slow!!
No stack was employed - subroutines worked via the caller writing the
return address into the first word of the called routine. Fun times!

BRENDA (BaRnardian Electronic Numerical Demonstration Apparatus) was a
7-bit machine (16 memory locations); it _was_ a serial machine, also
operating in ones complement, instead of the now-universal twos
complement. It looked like everybody's idea of a computer then: a wall
of filament bulbs (one for each bit in each memory location, plus the
other registers such as accumulator, prog. counter, etcetera). No
subroutines. It was the shape and size of the luggage space of a Hillman
Imp (British car of the time), as that's where HCP built it. It was
modular, using transistors - I believe he actually got the fourth form
[tenth grade I think] one year to make the modules.

I can still remember the opcodes:
Z clear accumulator
A address add the contents of address to accumulator
S address subtract the contents of address from accumulator
T address transfer accumulator to address
I address stop for input (which went into address)
J address jump to address+1
K address conditional jump (if negative IIRR) to address+1
E stop
Note that Z and E - 000 and 111 - had no parameter; a wily programmer
used those to store constants.

Mr. Parr produced a booklet, including some exercises; they started with
simple things like 3a+b (Z, A15, A15, A15, A14, E) and running totals
(I15, A15, J15), but leading up to the 50th example which was IIRR
calculate the highest common factor of two numbers (which I never
managed).
http://forum.6502.org/download/file....7446aed16b6825
d2bb7c5999023c
http://forum.6502.org/viewtopic.php?f=3&t=2333
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Q. How much is 2 + 2?
A. Thank you so much for asking your question.
Are you still having this problem? I'll be delighted to help you. Please
restate the problem twice and include your Windows version along with
all error logs.
- Mayayana in alt.windows7.general, 2018-11-1
  #8  
Old September 22nd 19, 07:26 AM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
VanguardLH[_2_]
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Posts: 1,453
Default What is the absolute smallest instruction set do you need to make a working computer?

Yousuf Khan wrote:

What's your guess? 100 instructions? 50 instructions? 10? Would you
believe just 1 instruction!? And that instruction is implied, you don't
even need an opcode for that! And you're not going to believe what that
one instruction is either! This video explains how it's possible.

https://youtu.be/jRZDnetjGuo


https://en.wikipedia.org/wiki/One_in...n_set_computer
Concept proposed back in 1956.

It is a computational model used for teaching. It would be too slow for
physical implementation. That it can be done doesn't mean anyone cares.
  #9  
Old September 22nd 19, 03:25 PM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
Yousuf Khan[_2_]
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Posts: 1,296
Default What is the absolute smallest instruction set do you need to makea working computer?

On 9/22/2019 2:26 AM, VanguardLH wrote:
https://en.wikipedia.org/wiki/One_in...n_set_computer
Concept proposed back in 1956.

It is a computational model used for teaching. It would be too slow for
physical implementation. That it can be done doesn't mean anyone cares.


Maybe, maybe not. It may not have been anything more than a curiosity in
the 50's. Back then memory was very slow, and the caching technologies
that have evolved over the decades was not available yet back then. So
back then you had to make sure you explicitly put everything into
registers. But these days, with your typical x86 machine being really a
RISC processor emulating a CISC processor, and they've come up with so
many automatic caching techniques that registers are no longer needed,
and you can really work directly on memory without any performance
penalties nowadays.

Yousuf Khan
  #10  
Old September 22nd 19, 04:25 PM posted to alt.comp.os.windows-10,alt.windows7.general,comp.sys.ibm.pc.hardware.chips,comp.sys.intel,alt.comp.hardware.amd.x86-64
pyotr filipivich
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Posts: 10
Default What is the absolute smallest instruction set do you need to make a working computer?

VanguardLH on Sun, 22 Sep 2019 01:26:19 -0500 typed in
alt.windows7.general the following:
Yousuf Khan wrote:

What's your guess? 100 instructions? 50 instructions? 10? Would you
believe just 1 instruction!? And that instruction is implied, you don't
even need an opcode for that! And you're not going to believe what that
one instruction is either! This video explains how it's possible.

https://youtu.be/jRZDnetjGuo


https://en.wikipedia.org/wiki/One_in...n_set_computer
Concept proposed back in 1956.

It is a computational model used for teaching. It would be too slow for
physical implementation. That it can be done doesn't mean anyone cares.


Martin Gardner had an article about a "theoretical" 'primitive
computer using pulleys and ropes in place of transistors (or tubes).
In theory it would work, in practice there would be too much
imprecision from the slack/stretch in the ropes for it to work.

--
pyotr filipivich
Next month's Panel: Graft - Boon or blessing?
 




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