Worker B found the exclusion detector's blind spot: opcode 0x08 (addi, traps
on overflow) appears in 7 of 1,666 worklist rows (frame adjustments
addi sp,sp,-28, loop counters) while 0 of 310 registered regions contains
one — the same disjointness signal as finding 26's R-type class. addiu (0x09)
is ubiquitous, so the 0x08 occurrences are the anomaly. Verified by the
coordinator from raw words: 7 rows, incl. 3 of partition A's 5 call-shape
rows (0x80011084, 0x800F3B10, 0x80010F30) and 0x800F3BB4 (previously
recorded as a separate coordinator negative — now explained by this class).
sf3_triage.trapping_arithmetic now counts opcode 0x08; worklist regenerated
(1,563 rows, excluded_trapping_arith=54). Synthetic test added.
P9-T5 route (a) widened: the immediate form is part of the class; the 7
ADDI rows are a ready-made minimal probe set for any cc1 candidate.
Also confirmed this cycle: the no-frame global-ra ISR family (ra saved to a
global, no stack frame — 0x801097A0 proved, 0x8010B420 pattern-transferred)
is a second library-asm class identical in kind to the CRT entry.
Christopher Williams
d1b9cf7ad1