86e52b01d0
confirmed three ways Chasing where the event code comes from, sub_821C5580 turned out to do two things worth having. For Q6 it arms the outer gate: li r11,3 ; stw r11,16(r28) is exactly the value sub_821C7850 tests before dispatching, which answers the "what does this+16 == 3 gate on" question I left open last iteration. It then passes r5 = [r27+4], an event read out of a structure, so the vocabulary is still not enumerable. Of the four callers of sub_821C7850, three pass constants -- 0, 0 and 5 -- and this one does not. The accident is a few instructions earlier: li r5, 1103 into a sound-play call. 1103 is a BGM cue id, BGM_103. That closes a residual I had written off as undecodable: which bank the menu plays. The cue table genuinely cannot say, since its BGM entries are numeric -- but the code can, and it checks out three independent ways. The census says BGM_103.slb is two waves of 3876864 and 3930112 bytes; the XMA probe at the main menu saw two stereo streams of 3876864 and 3930112 bytes. Byte for byte on both. That also corrects me. bgm-two-stems.md said those observed sizes matched no bank's declared waves and inferred the decoder gets a window rather than a whole wave. Wrong on both counts -- I had checked only the BGM_0xx rows of the census because that was the block on screen. METHOD gets it: check a measurement against the whole reference set, not the part you happened to be reading.