All four run exactly as written in DECOMPOSITION.md 5.6/5.7 and need no
change now that D+ and DNEGATE are call-free.
Checked against C at 32- and 64-bit cells, optimised and ASan+UBSan:
every edge-vector combination (M+ over all triples, D- and D= over all
50625 quadruples, D0= over all pairs) plus 20000 pseudo-random cases
weighted to equal low or high cells and low sums that wrap to 0.
Mutations of D0= and M+ are caught.
Headroom (data cells under args / return entries under return address):
M+ 6/4, D- 5/4, D0= 7/7, D= 5/3.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
