Worked on enhancing SIMD correctness, performance, and maintainability in the rust-lang/stdarch and rust-lang/rust repositories, focusing on AVX2 and AVX512BW support. Addressed a bug in the _mm512_bsrli_epi128 intrinsic to ensure accurate logical right shifting, and refactored internal masking and alignment logic for consistency and safety. Improved code maintainability by moving mask computations outside unsafe blocks and aligning behavior with SSSE3 standards. Contributed to the AVX SIMD module by refining 8-bit integer alignment, edge-case handling, and shifting logic. Utilized Rust, x86 intrinsics, and low-level programming techniques to deliver safer, more performant, and maintainable SIMD implementations.