Use statically calculated ~mask. This reduces the number of moves and registers necessary at the expense of an extra memory load. This is probably a good trade-off since we are not bound by memory uops in this loop.
Use a simple shift for the rotation.
* c/blake3_sse2_x86-64_unix.S: emulate pshufb using SSE2 instructions for x86_64 unix
* c/blake3_sse2_x86-64_windows_gnu.S: Likewise for x86_64 Windows GNU.
* c/blake3_sse2_x86-64_windows_msvc.asm: Likewise for x86_64 Windows MSVC.
Use two 16-bit shuffles: one for the low 64-bits and one for the high 64-bits.
* c/blake3_sse2_x86-64_unix.S: emulate pshufb using SSE2 instructions for x86_64 unix
* c/blake3_sse2_x86-64_windows_gnu.S: Likewise for x86_64 Windows GNU.
* c/blake3_sse2_x86-64_windows_msvc.asm: Likewise for x86_64 Windows MSVC.
Use two pinsrw and a 16-bit shift to insert the 32-bit integer at the desired location.
* c/blake3_sse2_x86-64_unix.S: emulate pinsrd using SSE2 instructions for x86_64 unix
* c/blake3_sse2_x86-64_windows_gnu.S: Likewise for x86_64 Windows GNU.
* c/blake3_sse2_x86-64_windows_msvc.asm: Likewise for x86_64 Windows MSVC.
Blend according to (mask & b) | ((~mask) & a).
* c/blake3_sse2_x86-64_unix.S: emulate blendvps using SSE2 instructions for x86_64 unix
* c/blake3_sse2_x86-64_windows_gnu.S: Likewise for x86_64 Windows GNU.
* c/blake3_sse2_x86-64_windows_msvc.asm: Likewise for x86_64 Windows MSVC.
Use a constant mask to blend according to (mask & b) | ((~mask) & a).
* c/blake3_sse2_x86-64_unix.S: emulate pblendw using SSE2 instructions for x86_64 unix
* c/blake3_sse2_x86-64_windows_gnu.S: Likewise for x86_64 Windows GNU.
* c/blake3_sse2_x86-64_windows_msvc.asm: Likewise for x86_64 Windows MSVC.
Wire up basic functions and features for SSE2 support using the SSE4.1 version
as a basis without implementing the SSE2 instructions yet.
* Cargo.toml: add no_sse2 feature
* benches/bench.rs: wire SSE2 benchmarks
* build.rs: add SSE2 rust intrinsics and assembly builds
* c/Makefile.testing: add SSE2 C and assembly targets
* c/README.md: add SSE2 to C build instructions
* c/blake3_c_rust_bindings/build.rs: add SSE2 C rust binding builds
* c/blake3_c_rust_bindings/src/lib.rs: add SSE2 C rust bindings
* c/blake3_dispatch.c: add SSE2 C dispatch
* c/blake3_impl.h: add SSE2 C function prototypes
* c/blake3_sse2.c: add SSE2 C intrinsic file starting with SSE4.1 version
* c/blake3_sse2_x86-64_{unix.S,windows_gnu.S,windows_msvc.asm}: add SSE2
assembly files starting with SSE4.1 version
* src/ffi_sse2.rs: add rust implementation using SSE2 C rust bindings
* src/lib.rs: add SSE2 rust intrinsics and SSE2 C rust binding rust SSE2 module
configurations
* src/platform.rs: add SSE2 rust platform detection and dispatch
* src/rust_sse2.rs: add SSE2 rust intrinsic file starting with SSE4.1 version
* tools/instruction_set_support/src/main.rs: add SSE2 feature detection