View unanswered posts | View active topics It is currently Fri Mar 29, 2024 7:31 am

Search found 157 matches
Search these results:

 Search 
Author Message

 Forum: General Discussions   Topic: One K Computing - Roll Your own Challenge

Posted: Tue Feb 02, 2021 5:00 pm 

Replies: 7
Views: 2863

It's an interesting metric on code density and the expressive power of an ISA: to what degree do 1k 16 bit words give you as much scope as 2k 8 bit bytes. I think this is one of the reasons that Wozniak's SWEET16 retained an 8-bit instruction size. If a 16-bit literal or jump address was needed, it...

 Forum: General Discussions   Topic: One K Computing - Roll Your own Challenge

Posted: Sun Jan 31, 2021 8:46 pm 

Replies: 7
Views: 2863

Ben,

The purpose of this challenge is to do more with less.

You can easily define a virtual cpu in 2K bytes and then you have a full 64K of RAM to execute code on it.

I'm not excluding 32-bit cpus, but the ROM limit will remain at 2048 bytes.

 Forum: General Discussions   Topic: Musys, Minicomputers and Mouse........

Posted: Sat Jan 30, 2021 2:26 am 

Replies: 1
Views: 2005

Another retrocomputer rabbit hole.... In 1967 Peter Zinovieff acquired a PDP-8/S for the then princely sum of £5000. (About the cost of a 4-bed London house). With David Cockerell assembling hardware, Peter Grogono doing coding and Tristram Cary working on musical compositions, together they created...

 Forum: General Discussions   Topic: One K Computing - Roll Your own Challenge

Posted: Fri Jan 29, 2021 12:22 am 

Replies: 7
Views: 2863

Nearly 4 years ago, three of our well respected forum members sat down one evening over a curry and came up with the One Page Computing OPC Challenge. http://anycpu.org/forum/viewtopic.php?f=3&t=372#p2400 I realise that in these strange times, sitting down for a curry with friends might seem an ...

 Forum: General Discussions   Topic: One Page Computing - roll your own challenge

Posted: Thu Jan 28, 2021 2:06 pm 

Replies: 107
Views: 91400

Hi All, Today I have looked at the five simulations for the 16-bit (and 12-bit) cpus: Blue 16 instructions, 16-bit wordsize, direct addressing only. 4K words memory PDP-8 8 main instructions, plus OPR extensions. 12-bit wordsize. Direct and indirect addressing modes. 4K words memory J1 Stack machine...

 Forum: General Discussions   Topic: One Page Computing - roll your own challenge

Posted: Tue Jan 26, 2021 8:24 pm 

Replies: 107
Views: 91400

This week I have been looking at the C simulations of some experimental and commercial cpus. 1. Blue https://brainwagon.org/2011/07/07/a-basic-simulator-for-caxton-fosters-blue-architecture/ 2. PDP-8 https://github.com/KedalionDaimon/DEC-PDP-8-on-Arduino 3. 8080 https://github.com/companje/Altair880...

 Forum: General Discussions   Topic: The Cray-1 implementation: an 80MHz machine

Posted: Mon Jan 18, 2021 7:54 pm 

Replies: 18
Views: 5976

The 80MHz clock frequency, and 160 MFLOPS, whilst non-impressive today, was not it's only secret weapon. I was informed that it had a huge memory bandwidth on account of its vector processing architecture so that vast quantities of data could be processed in parallel. For 10 million 1976 dollars - I...

 Forum: Hardware in general   Topic: Bit Serial CPUs

 Post subject: Re: Bit Serial CPUs
Posted: Sat Dec 12, 2020 6:33 pm 

Replies: 19
Views: 7684

Another update on the bit serial cpu project. I am still using H Neeman's "Digital" simulator - which is proving to be a useful design tool. I took the rational decision of separating the ALU from the memory so that I could focus on each as a separate entity. The ALU section boils down to ...

 Forum: Hardware in general   Topic: Bit Serial CPUs

 Post subject: Re: Bit Serial CPUs
Posted: Fri Dec 11, 2020 12:23 am 

Replies: 19
Views: 7684

Here's the latest update on my bit serial cpu project. My design was getting too complicated and approaching 30 IC packages, so I took a step back to re-assess the design. I eventually realised that most modern memory hardware is based on parallel buses - so I acknowledged @EdS advice and decided th...

 Forum: Hardware in general   Topic: Bit Serial CPUs

 Post subject: Re: Bit Serial CPUs
Posted: Tue Dec 08, 2020 5:11 pm 

Replies: 19
Views: 7684

My experimental bit serial ALU is now available to view using "Digital" from my Github repository https://github.com/monsonite/Bit_Serial Here is the circuit description for the latest design. Circuit Description. Bit Counter and Bit Time Decoder The heart of the machine is a free running ...

 Forum: Hardware in general   Topic: Bit Serial CPUs

 Post subject: Re: Bit Serial CPUs
Posted: Mon Dec 07, 2020 10:31 pm 

Replies: 19
Views: 7684

The bit serial project progresses slowly - due to a number of "schoolboy errors". I loaded two sets of sequence data into the ROMs and started the simulation - in this case adding pairs of 8-bit numbers. All appeared to be going well for the first couple of additions but then things rapidl...

 Forum: Hardware in general   Topic: Bit Serial CPUs

 Post subject: Re: Bit Serial CPUs
Posted: Sun Dec 06, 2020 2:00 pm 

Replies: 19
Views: 7684

My bit serial exploration continues this weekend by way of H. Neeman's "Digital" simulator. The first challenge was to create a source of correctly timed serial data. Almost every new processor starts with its memory sub-system - so I thought that would be a good place to start. The circui...

 Forum: General Discussions   Topic: The Cray-1 implementation: an 80MHz machine

Posted: Sun Nov 22, 2020 7:38 pm 

Replies: 18
Views: 5976

I remember seeing the Cray-1a (Serial Number 011) at the Science Museum, London many years ago. As well as being an iconic design from the late 1970's, and very expensive office furniture - it was the hand assembled backplane wiring that was most impressive. I thought to myself - how can this rats-n...

 Forum: Hardware in general   Topic: Bit Serial CPUs

 Post subject: Re: Bit Serial CPUs
Posted: Sun Nov 22, 2020 6:38 pm 

Replies: 19
Views: 7684

Some further research on bit serial technology shows that it was common-place in the Japanese desktop calculators around 1968-1970. Some of the first MSI ICs produced in Japan in the late 1960's were shift registers and serial adder/subtractor ICs intended for the calculator market. The link below f...

 Forum: Hardware in general   Topic: Bit Serial CPUs

 Post subject: Re: Bit Serial CPUs
Posted: Sat Nov 21, 2020 2:59 pm 

Replies: 19
Views: 7684

Ben - Thanks for the heads-up on the 74LS384 and '385. I was not aware that these devices even existed, but I guess, as is the case with a lot of older TTL, it was created to fulfill a definite requirement - at a particular time in history. Sadly few of these "interesting" devices are arou...
Sort by:  
Page 3 of 11 [ Search found 157 matches ]



Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software