781a82cc0a
Native rlwinm/rlwimi/rlwnm (32-bit rol+and, mask folded to a compile-time
constant) and rldicl/rldicr (64-bit rol + 64-bit mask), including the Rc
recording forms via emit_cr0_from_reg (test + signed setcc into cr[0],
reusing the compare CR path). rlw_mask/rld_mask replicated as
compile-time helpers. Differential test rotates_match: 2000 seeds x
{rc,non-rc} x {32,64-bit} x xer_so, asserting full GPR+CR+counters.
Golden n200m BYTE-IDENTICAL with and without XENIA_JIT (12 tests green).
Throughput 4.7->4.55s (interp ~3.9s): opcode coverage now at diminishing
returns; the remaining gap is memory-traffic-per-instruction (no register
caching) + fallback tax, not missing opcodes -> Phase 4 (register cache)
is the crossover lever.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>