It takes me back! I wrote my first one in Z80 assembler a looong time ago as part of my first real job (~1990) which was used to error correct a satellite chan

It takes me back! I wrote my first one in Z80 assembler a looong time ago as part of my first real job (~1990) which was used to error correct a satellite channel (bandwidth about 19.2 Kbit/s IIRC)! It used lots of table lookups to make things run at a reasonable speed, but the tables couldn't be too big since there was only an 8K EEPROM. The Z80 code only did d=3 codes (so could correct 1 error or detect two). Working out how to solve a quadratic equation over GF(256) in Z80 assembler was my personal highlight!