Summary

The Excellon drill parser (src/drill.c) defines many G-codes and M-codes in its enums (drill_g_code_t, drill_m_code_t) but only handles a subset. Commands that are parsed but not handled fall through to "unsupported" error messages, and commands not even parsed are silently ignored or reported as unknown.

This issue tracks the gap between what the parser defines and what it actually handles, prioritized by real-world impact.

G-codes

Handled

Handled (ignored — machine-only, no visual effect)

M-codes

Handled

Handled (ignored — machine-only, no visual effect)

Defined but NOT handled

Progress

• G02/G03 arc routing (I/J offsets) — Merged in fix: support Excellon G02/G03 arc routing with I/J center offsets #298. CW/CCW arc commands with I/J center offsets, reusing the Gerber calc_cirseg_mq algorithm.
• G02/G03 arc routing (A radius) — PR fix: support A (radius) parameter for Excellon G02/G03 arcs #345 (open). Adds A radius parameter support as an alternative to I/J offsets, converting radius to center offsets via chord geometry.
• G87 routed slot canned cycle — PR feat: implement Excellon G87 routed slot canned cycle #300 (open). Creates routed line segments via drill_add_route_segment() instead of modifying drill flashes like G85.
• M70/M80/M90 axis transforms — PR feat: implement Excellon M70/M80/M90 axis transform commands #301 (open). Swap axis and mirror commands affect coordinate interpretation for bottom-side drill files.
• M25/M01/M02 pattern repeat — PR feat: implement Excellon M25/M01/M02 pattern repeat #304 (open). M25 begins pattern recording, M01 ends it, M02 replays buffered drills and route segments at X/Y offset.
• G32/G33 routed circle — PR feat: implement G32/G33 routed circle canned cycles #305 (open). Full 360° CW/CCW circle canned cycles using drill_add_circle_segment() with cirseg arc data.
• Machine-only codes acknowledged — PR Acknowledge machine-only Excellon G/M-codes #306 (open). 17 G-codes and 10 M-codes logged at NOTE level with grouped stats counters.