When you look at typical FGPA emulator source code, it often looks pretty close to software emulator code ported to VHDL/Verilog instead of an attempt to re-create the original reverse-engineered 'transistor-level design' which would automatically reproduce any 'undocumented behaviour' of the original chip (like http://www.visual6502.org/JSSim/index.html)
As such, an FGPA emulator isn't necessarily any closer to the original hardware behaviour than a software emulator. I guess the main advantage of FGPA is better performance on lower cost hardware.
> As such, an FGPA emulator isn't necessarily any closer to the original hardware behaviour than a software emulator. I guess the main advantage of FGPA is better performance on lower cost hardware.
The price of the majority of FPGA chips are really expensive compared even against cheap (yet still way more powerful) SoCs (like really cheap ARM CPUs that are used in sub $100 handheld emulators). Also, technically a FPGA based emulator could be more efficient compared emulating everything in software, but AFAIK even Analog Pocket is not really that better in battery life compared to say a Miyoo Mini + (maybe because a ARM SoC have better energy management, but I don't know).
I think really the main hype of FPGA is lower input latency, that is really difficult to archive with software emulation. There are still some tricks you can do in software that reduces the input latency significantly, but they generally are expensive to compute [1], so it wouldn't be feasible to be done in a cheap handheld device (at least yet).
Many people think an FPGA is automatically accurate emulation because it's "hardware" and the original console is "hardware".
But the FPGAs are based on C software emulators because that's where all the knowledge in the world of how to emulate the original system is kept. You can't translate original hardware to Verilog and skip the figuring out how it works process.
You're getting into the weeds and will get different answers based on semantics, here.
A FPGA emulation isn't inherently better than a CPU-based emulation of any given chip; it's not more authentic because it still lacks the particular quirks of any old CPU that are associated with the way the hardware was laid out, path lengths, imperfections etc.
I'm glad it's introducing FPGA programming to a wider audience because FPGAs are probably going to become more important going forward - and are probably going to be what keeps Intel alive - but it doesn't make the emulator inherently better.
