The GE reads the source in aligned 16-byte blocks, four at a time, into a
buffer of four destination-aligned 16-byte slots, and a read of a block a
slot holds returns the slot's bytes, stale ones included. So a transfer
shifting a row right by less than 64 bytes reads some of what it has just
written, in a pattern that isn't a forward or backward copy. Fitted to
ppsspp-re geprobe exp219 and exp220 on hardware (562 of 570 cases exact).
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>