Re:“Land initial Rust MP4 parser and unit tests”
by haberman on Thursday June 18, 2015 @04:47PM
(#9741523)
This looks like a good start (though experimental). If it supported something like AltaVec's vec_any_eq() intrinsic on its u8x16 type, that would do the trick. vec_any_eq() takes a vector and a value and returns true if any element of the vector equals the value.
On x86 with SSE, this could generate a sequence of two instructions: pcmpeqb (do 16 byte-wise compares) followed by pmovmskb (collect the 16 comparison results into a single byte). Then you'd get the same efficiency as what Clang does (Clang searches 8 bytes at a time for a '/' character when skipping over comments).
Re:“Land initial Rust MP4 parser and unit tests”
by jroesch on Thursday June 18, 2015 @07:50PM
(#9742285)
Huon is working on SIMD full time at Mozilla this summer as far as I know. We should see more mature support materialize in the next couple of months for sure.
On x86 with SSE, this could generate a sequence of two instructions: pcmpeqb (do 16 byte-wise compares) followed by pmovmskb (collect the 16 comparison results into a single byte). Then you'd get the same efficiency as what Clang does (Clang searches 8 bytes at a time for a '/' character when skipping over comments).