[gmh5225]

Narrow ARM64 LDSMAX/LDSMIN operations could store the unsigned comparison result: for example, signed byte max(16, -17) stored -17. The nonparallel TCG fallback reused the result-extension flag to choose operand signedness, although ARM returns the old narrow memory value zero-extended.

Keep operand sign extension separate from the original load/store descriptor and returned value. The shared atomic-operation table explicitly marks signed min/max, preserving the parallel helper path and other atomic operations. Direct Unicorn C API regressions cover 64 min/max encodings, six independent operand vectors and four result-register layouts (1,536 executions), including aliases and XZR.

Validation: the original engine failed 384 memory-result checks; the fixed engine passes all 1,536 executions. Complete ARM64, ARM and x86 unit binaries pass, as do NeverD software-backend checks for 168 LSE encodings. No native ARM64 backend execution is claimed by these host tests.

The ARM64 wheel run also exposed an old invalid-jump regression whose one-instruction budget could stop at the jump before the expected target fetch. It now tests that fetch with a bounded timeout instead of depending on translator-specific stop ordering. The corrected regression passes locally.