Search found 66 matches

by Sugarplum
01 Jul 2022, 03:15
Forum: Hardware and software hacking
Topic: Musings on compatibility breaking changes.
Replies: 4
Views: 134

Re: Musings on compatibility breaking changes.

I had figured that if I were making mods, I'd expand the left shift to be full and add a right shift. The opcode space can be used for those to give the desired distance and possibly the direction. Plus I'd love to add a table-based ALU to add multiplication and division. I had considered other arch...
by Sugarplum
30 Jun 2022, 10:19
Forum: Hardware and software hacking
Topic: Would emulating vCPU on a Propeller 2 be feasible?
Replies: 9
Views: 161

Re: Would emulating vCPU on a Propeller 2 be feasible?

I think we sorta lost the intention of the thread. It is nice what others are doing on more modest controllers, and I applaud those who are doing those. Thank you for the links and the controller recommendations. The difference here is that the Propeller 2 has 8 cogs, and the challenge is to maximiz...
by Sugarplum
28 Jun 2022, 14:25
Forum: Hardware and software hacking
Topic: Would emulating vCPU on a Propeller 2 be feasible?
Replies: 9
Views: 161

Re: Would emulating vCPU on a Propeller 2 be feasible?

If you want to just emulate the Von Neumann vCPU 16bit instruction set, that's pretty trivial on any decent modern architecture. If you want 100% .gt1 compatibility then you have to emulate all the Sys calls, zero page registers, audio registers, VBlank registers, scanline VTable, etc, etc. No so t...
by Sugarplum
28 Jun 2022, 00:30
Forum: Hardware and software hacking
Topic: Would emulating vCPU on a Propeller 2 be feasible?
Replies: 9
Views: 161

Would emulating vCPU on a Propeller 2 be feasible?

I wanted to do the 75-100 Mhz Gigatron, and while I think that's possible if I redesign the architecture and go for a 4-stage pipeline, I don't know if I can pull it off with the way memory prices have gotten. While that's against Marcel's original philosophy, I wanted to do the CU and the ALU in SR...
by Sugarplum
11 Jun 2022, 06:00
Forum: Hardware and software hacking
Topic: Gigatron Clone Ideas
Replies: 46
Views: 1675

Re: Gigatron Clone Ideas

My idea on that would be to put the 2 Gigatrons on opposing clocks and make the RAM only available to the active one. So concurrent DMA where 1 works half the time and the other works half the time. So they each get to use the memory during their turn. So round-robin arbitration. I can think of diff...
by Sugarplum
07 Jun 2022, 03:55
Forum: Hardware and software hacking
Topic: Multicore Gigatron
Replies: 0
Views: 118

Multicore Gigatron

In an old thread, Marcel gave a way to join 2 Gigatrons. I recently thought of a different way to do it. Someone could take 2 Gigatrons, use a 2-phase clock, and connect them using the memory. So let one do all the I/O and the other just run vCPU, and a somewhat simpler one due to not needing to car...
by Sugarplum
07 Jun 2022, 03:21
Forum: Hardware and software hacking
Topic: Gigatron Clone Ideas
Replies: 46
Views: 1675

Re: Gigatron Clone Ideas

I recently thought of a different idea. Maybe if someone were to take 2 Gigatrons, use a 2-phase clock, and connect them at the memory. So let one do all the I/O and the other just run vCPU, and a somewhat simpler one due to not needing to care about time slices. The I/O one could handle video, soun...
by Sugarplum
15 Apr 2022, 05:23
Forum: Hardware and software hacking
Topic: Seeking RAM for upgrade (US)
Replies: 9
Views: 804

Re: Seeking RAM for upgrade (US)

It's an assembly/soldering optimisation, just solder the pins together and you don't have to worry about extra wires, routing, etc. The RAM could care less which bytes your address lines access, as long as the address mapping is always consistent and always matches the 64k address space in a 1:1 fa...
by Sugarplum
31 Mar 2022, 00:00
Forum: Hardware and software hacking
Topic: Seeking RAM for upgrade (US)
Replies: 9
Views: 804

Re: Seeking RAM for upgrade (US)

You can get a 128KB one and wire the extra address pins together. https://www.digikey.com/en/products/detail/alliance-memory-inc/AS6C1008-55PCN/4234576 Or you can bite the bullet and build a 128KB expansion which also gives you SPI port usable with a SD card. (see https://forum.gigatron.io/viewtopi...
by Sugarplum
11 Mar 2022, 13:36
Forum: Hardware and software hacking
Topic: Who wants to see a 100 Mhz Gigatron?
Replies: 12
Views: 1656

Re: Who wants to see a 100 Mhz Gigatron?

Would an instruction where you multiply something in memory and then jump to that address (all in a single cycle) be helpful in designing a more efficient vCPU? So you could space out the landings of the jump table wider. And if I were to add that, what would be more helpful? Causing the extra bits ...