Cover the fpscr-free FP moves. Validated bit-exact via the in-process
differential harness on a full boot+movie run (movie plays, clean exit):
checked 146.2M blocks, 39.82% native (up from 38.78%), MISMATCHES=0
Coverage (all fpscr-free — pure data movement, no rounding flags):
* FP loads: lfs/lfsx (load single, IEEE-widen to the f64 FPR via
read32 -> bitcast F32 -> fpromote F64), lfd/lfdx (pure 64-bit bit copy).
* FP stores: stfs/stfsx (fdemote f64 -> f32 -> bitcast i32 -> write32),
stfd/stfdx (pure 64-bit bit copy). Stores reuse the reservation-kicking
write trampolines.
* FP reg moves (Rc=0 only — the `.` forms update CR1 from fpscr): fmr (bit
copy), fabs (band_imm i64::MAX, clear sign), fneg (bxor_imm i64::MIN, flip
sign) — bit ops that exactly match Rust f64 copy/abs/neg.
Note: the +1% lift is small because the movie's FP-heavy blocks almost always
mix an FP load with FP *arithmetic* (fadds/fmuls/fmadds), which stays
uncovered — it updates fpscr (FPRF/FI/FR, invalid-op flags), not yet lowered.
The moves that landed are the pure data-copy blocks.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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