Imaginary 64-bit 680x0

[psxphill]

Is it really a 64 bit 680x0 though?

It kinda reminds me more of a 64bit MIPS cpu.

[psxphill]

Obviously a JIT would be better but that's a long way off.

Even lazy flag calculation in an interpreter would be a win, I did that when I wrote an interpreter in 6502 assembler.

The no flags is what made me think of MIPS, but then 88100 doesn't appear to have flags either. But the 68k does.

You can create a virtual CPU if you want, I just think it's not inspired enough by the 68k to make a big deal out of it.

6502 was inspired by pdp11, but that was never once mentioned in documentation.

[psxphill]

I imagine the biggest reason not to have FPGA implementations would be that they're all still in mainstream use.

I think it comes down to cost of the FPGA. Something like the DE10 Nano is pushing it running a 486 PC. Apollo isn't particularly better.

If you simplify your CPU then sure you could do a 256 bit one in an FPGA, but it wouldn't necessarily be able to do anything worthwhile.

Similar to how the TI99/4 had a 16 bit CPU but was so crippled that it was outperformed by machines with 8 bit CPU's

[psxphill]

I was thinking the other day about going the opposite direction back to 8 bit just on faster/tighter packages...

Ultimate 64 has a nearly 48mhz 6510, mega65 gets to around 40mhz, turbo chameleon & supercpu does 20mhz.

supercpu & mega65 have cpu extensions that allow direct access to more than 64k, but you are coding specifically for one of the two platforms and nothing else.