Retro Ramblings

Musings on FPGA and Retro Computing

“MIF is not supported?” Yes it is!

Posted on January 30, 2021 by AMR

2021-01-30

I’ve just bought a couple of the ridiculously cheap DECA MAX10 dev boards from Arrow and one of the first projects I attempted to port to it gave me an error message I wasn’t expecting:

Error (276003): Cannot convert all sets of registers into
RAM megafunctions when creating nodes. The resulting number
of registers remaining in design exceeds the number of
registers in the device...

Hmmm, OK, what’s going on here? For some reason the ROM in my project isn’t getting recognised and implemented as initialised block RAM – what gives?

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Bug fixes and a new instruction…

Posted on January 22, 2021 by AMR

The EightThirtyTwo ISA – Part 23 – 2021-01-22

It’s been some time since I’ve made any significant changes to the EightThirtyTwo ISA, CPU or compiler backend, and this is mostly because I’ve been busy using it in real projects.

EightThirtyTwo’s original purpose, apart from the obvious learning exercise, was to be the supporting CPU in the AGA Minimig core for the Turbo Chameleon 64, and it’s performed this function quite nicely: it’s significantly smaller than the secondary TG68 used in the ECS core, and somewhat smaller than the OpenRISC cores that were used in some other Minimig variants, while using fewer memory blocks due to its logic-based register file and reasonably good code-density.

Nevertheless there are always bugs to be fixed and improvements to be made.

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