A Moogle  🏳️‍🌈 💻 🎮 🎶 🇸🇪

As much as I adore seeing FPGA-based emulation, I really wish the community would stop putting forth what amounts to propaganda, which gets consumed uncritically by non-technical article writers. It doesn't involve emulating machines on a transistor level. It just plain doesn't.

An FPGA, for the most part, is a massive piece of silicon that contains a boatload of what are known as "Logic Elements", each of which can accept a set of inputs, and generate a set of outputs based on a lookup table, which are dynamically "wired" together by *software*.

The bitstream that gets uploaded to an FPGA, unless it's concretely set in some ROM, is ostensibly software. It can be changed at run-time to configure the functionality of those logic elements. It is far more akin to software than even firmware.

When a CPU runs microcode is it hardware or software? If someone turned the verilog into an ASIC is it still software?

If someone turns the Verilog into an ASIC, is it suddenly a more accurate representation of the hardware?

No. But if the verilog was derived from a chip decap it is.

It's still a reimplementation. Take the 68000 for instance, all its internals uses latches while a fpga can only do flip-flops. fx68k is beautiful and externally identical to the real thing, but the internals are very different in practice.

Documenting those differences between emulation and the real thing is important. Many games in MAME are rendered using a frame buffer and blitting instead of line rasterization. The end result is identical from a player's perspective but not to someone that is fixing hardware