[aewens]

> A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturing – hence the term field-programmable.

> FPGAs contain an array of programmable logic blocks, and a hierarchy of reconfigurable interconnects allowing blocks to be wired together. Logic blocks can be configured to perform complex combinational functions, or act as simple logic gates like AND and XOR. In most FPGAs, logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory.[1] Many FPGAs can be reprogrammed to implement different logic functions, allowing flexible reconfigurable computing as performed in computer software.

The above being from the FPGA Wikipedia page[0].

So yes, it is done “in software”, but FPGAs is fancy hardware that can reprogrammed to act as new hardware on the fly using software. Many are implemented as PCI devices, so they could interact with the rest of the system over the PCI bus.

[0] https://en.m.wikipedia.org/wiki/Field-programmable_gate_arra...

[bo1024]

Sorry, my question wasn't clear. What I am asking is whether the FPGA was being simulated in a VM, or whether the OS they built was running on a physical FPGA. And if the latter, how did the OS handle drivers for other components.

[VLM]

Apparently simulated.

You can see in the UART code for example:

https://github.com/nyuichi/GAIA3/blob/master/hardware/Rx.vhd

file input_file : ft open READ_MODE is input_filename;

read(input_file, c);

data <= std_logic_vector(to_unsigned(character'pos(c), 8));

And so on and so forth, to pump a file on the simulation PC into a VHDL logic array one byte at a time as a simulation of a UART.

Would be pretty funny if the above is the "wrong" repo for the story, but it is at least "an implementation" of the GAIA architecture, if not "the implementation" from the story.