microcode/

The microcode control store — the single source of truth for what every opcode does. The same images burned to the four control-card EPROMs are what the emulator interprets, so emulator and hardware behave identically by construction.

File	Purpose
genucode.py	Generator — defines the opcode table (OPC), the 32-bit control word, and per-opcode microcode step sequences; emits u0–u3.bin. The assembler imports its OPC.
gen_progguide.py	Renders the instruction-set programmer's guide PDF into ../docs/.
u0–u3.bin	The four 28C64 control-store images (word bits 0–7 / 8–15 / 16–23 / 24–31). Loaded by the emulator and copied to the CWD by the tests.

The control word is addressed by IR | step<<8 | cond<<12. The bit layout lives in genucode.py and is mirrored by the control card's pipeline latches — see GLOSSARY.md and docs/p8x-system-design.md §3.2.

Build

cd ../emulator && make ucode      # runs genucode.py -> u0-u3.bin

Generators are canon. Never hand-edit the .bin images — change genucode.py and regenerate. The burnable Intel HEX for an EEPROM programmer is produced into ../rom/ by make rom (this directory holds only the .bin the emulator and tests load).