Building the network module took about a month, but writing the compiler took much more time.
Impressive stuff.
I've dabbled wuth making my own ISA and softcore CPU in FPGA, but getting C code to compile has been a bit of a blocker.
I know there are some compilers one could try to port but my ISA is kinda esoteric so not straight forward, and so I considered just writing from scratch like you have.
Same. I tried digging into exsiting compilers, but they are either unsuitable at all or too complicated (clang).
When building my system, I was inspired by 8 bit retro computers like ZX Spectrum. Their architecture is straightforward and easy to understand.
Electronics just fascinates me, but I can't really point out a single source which gave me the insight. A lot of playing around with transistors, microcontrollers, logic gates gives the intution how to design stuff.