To me, it's plausible one might be able to make a similarly small RISCY-V02 on a 70s Rubylith NMOS process with dynamic logic, using pass transistors and tristate busses, all laid out by hand. But I definitely can't do that, and even if I could, I'd have no way to validate that it actually works.
Best I could do was an A/B comparison on a modern process: a clean Verilog model of RISCY-V02, and a clean Verilog model of a 6502, both run through a modern synthesis process for TinyTapeout. Same slosh, inoptimality, and behavior. So, this is a static CMOS design, like the 65C02, on a modernish process node. That being said, the 65C02 had around 11K transistors, so we're not too far off.
This establishes horseshoes and hand grenades plausibility, but basically nothing else. But, it's also a pretty nifty CPU design if I do say so myself!
Impressive project! But I have question:
The Highlights section near the top of the README says:
13,844 SRAM-adjusted transistors (vs 13,176 for 6502 on same process)
But the Wikipedia article on the 6502 says it only had 3,510 transistors, and says the Monster6502 was built with 3,218 discrete transistors.
Why the discrepancy?
To me, it's plausible one might be able to make a similarly small RISCY-V02 on a 70s Rubylith NMOS process with dynamic logic, using pass transistors and tristate busses, all laid out by hand. But I definitely can't do that, and even if I could, I'd have no way to validate that it actually works.
Best I could do was an A/B comparison on a modern process: a clean Verilog model of RISCY-V02, and a clean Verilog model of a 6502, both run through a modern synthesis process for TinyTapeout. Same slosh, inoptimality, and behavior. So, this is a static CMOS design, like the 65C02, on a modernish process node. That being said, the 65C02 had around 11K transistors, so we're not too far off.
This establishes horseshoes and hand grenades plausibility, but basically nothing else. But, it's also a pretty nifty CPU design if I do say so myself!