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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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What is the absolute smallest instruction set do you need to makea working computer?
Yousuf Khan wrote on 9/22/2019 6:59 AM:
On 9/22/2019 1:47 AM, Jeff Barnett wrote: The machine I'm trying to recall is Turing Complete. In other words it can implement an interpreter that can "execute" any Turing machine with any input tape - it's a theoretical machine. If you are talking about a machine with real components, that's a horse of a different color and quite puny in comparison. This 2 register machine, with few instructions was all the theoretical rage some 60 or 70 years ago and was described in many text books. I thought your original question was fishing for what I described. Well, I don't know anything about "Turing Complete" machines. If such Turing machines can be run through any current general purpose computer architecture, then this theoretical machine should be able to run it too. The concept is not about artificial intelligence, but about general purpose computing at its most basic level. About 2 or 3 decades ago, we had the debate about RISC vs. CISC architectures. Without getting into debates about which of those concepts won in the end, this is taking that debate to the next level, and asking what is the most basic set of instructions that can eliminate all other instructions? So they've eliminated every other instruction, and replaced it with this one instruction, called SUBLEQ, "Subtract Less Than or Equal To". It only does subtractions on data, and branches only when the result is less than or equal to zero. So this is the ultimate RISC architecture, the OISC (One Instruction Set Computing) architecture. The page below links to an OISC interpreter and tools. Oleg Mazonka - Languages - SUBLEQ http://mazonka.com/subleq/ What I described has zip to do with artificial intelligence and could never be implemented in real circuits - the registers are of whatever size the computation needs. It's like a TM tape can get as long as necessary. Note that the theoretical machine had no memory other than its two registers and a "code" store. It also worked with minimum instructions but could do any computable task. -- Jeff Barnett |
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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 |
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What is the absolute smallest instruction set do you need to make a working computer?
In message , pyotr
filipivich writes: [] 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. Babbage (arguably only with modern materials) made a mechanical machine work. There are the mechanical equivalents of squaring circuits, thresholds etcetera. Electronic computers could be made to work with three or four voltage levels rather than two - it just reduces the noise margin, which puts limits on speed and distances. Presumably a pulleys/ropes machine could be made, as long as there were thresholds, and the mechanical equivalents of amplifiers (a rope-operated clutch perhaps? I'm not really a mechanical engineer). -- J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf "Flobalob" actually means "Flowerpot" in Oddle-Poddle. |
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What is the absolute smallest instruction set do you need to make a working computer?
"J. P. Gilliver (John)" on Sun, 22 Sep 2019
21:15:45 +0100 typed in alt.windows7.general the following: In message , pyotr filipivich writes: [] 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. Babbage (arguably only with modern materials) made a mechanical machine work. There are the mechanical equivalents of squaring circuits, thresholds etcetera. Electronic computers could be made to work with three or four voltage levels rather than two - it just reduces the noise margin, which puts limits on speed and distances. Presumably a pulleys/ropes machine could be made, as long as there were thresholds, and the mechanical equivalents of amplifiers (a rope-operated clutch perhaps? I'm not really a mechanical engineer). It is funny in a way. Garden was reporting a supposed "discovery" of a "computer" discovered on a south pacific island. Yes, one could probably be made to work. Wintergatan - Marble Machine has made what was originally a CGI video into a working machine. https://www.youtube.com/watch?v=IvUU8joBb1Q A fascinating study in its own right. -- pyotr filipivich Next month's Panel: Graft - Boon or blessing? |
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What is the absolute smallest instruction set do you need to makea working computer?
On 2019-09-22 8:36 p.m., pyotr filipivich wrote:
"J. P. Gilliver (John)" on Sun, 22 Sep 2019 21:15:45 +0100 typed in alt.windows7.general the following: In message , pyotr filipivich writes: [] 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. Babbage (arguably only with modern materials) made a mechanical machine work. There are the mechanical equivalents of squaring circuits, thresholds etcetera. Electronic computers could be made to work with three or four voltage levels rather than two - it just reduces the noise margin, which puts limits on speed and distances. Presumably a pulleys/ropes machine could be made, as long as there were thresholds, and the mechanical equivalents of amplifiers (a rope-operated clutch perhaps? I'm not really a mechanical engineer). It is funny in a way. Garden was reporting a supposed "discovery" of a "computer" discovered on a south pacific island. Yes, one could probably be made to work. Wintergatan - Marble Machine has made what was originally a CGI video into a working machine. https://www.youtube.com/watch?v=IvUU8joBb1Q A fascinating study in its own right. Absolutely wonderful machine and a brilliant inventor/builder. I didn't know it existed. Rene |
#17
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What is the absolute smallest instruction set do you need to make a working computer?
Rene Lamontagne on Sun, 22 Sep 2019 22:31:28 -0500
typed in alt.windows7.general the following: On 2019-09-22 8:36 p.m., pyotr filipivich wrote: "J. P. Gilliver (John)" on Sun, 22 Sep 2019 21:15:45 +0100 typed in alt.windows7.general the following: In message , pyotr filipivich writes: [] 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. Babbage (arguably only with modern materials) made a mechanical machine work. There are the mechanical equivalents of squaring circuits, thresholds etcetera. Electronic computers could be made to work with three or four voltage levels rather than two - it just reduces the noise margin, which puts limits on speed and distances. Presumably a pulleys/ropes machine could be made, as long as there were thresholds, and the mechanical equivalents of amplifiers (a rope-operated clutch perhaps? I'm not really a mechanical engineer). It is funny in a way. Garden was reporting a supposed "discovery" of a "computer" discovered on a south pacific island. Yes, one could probably be made to work. Wintergatan - Marble Machine has made what was originally a CGI video into a working machine. https://www.youtube.com/watch?v=IvUU8joBb1Q A fascinating study in its own right. Absolutely wonderful machine and a brilliant inventor/builder. I didn't know it existed. It is a fascinating machine, both from the design concept through to the latest build. Fascinating as well are the machinist bits (the variable speed clutch to adjust timing for the kick drum). In my boxes of book I have the 4 volume set of "Ingenious Devices" - or "How we did this before stepper motors and computer controls." -- pyotr filipivich Next month's Panel: Graft - Boon or blessing? |
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