avx

I'm developing optimizations for my 3D calculations and I now have: a " plain " version using the standard C language libraries, an SSE optimized version that compiles using a preprocessor #define USE_SSE , an AVX optimized version that compiles using a preprocessor #define USE_AVX Is it possible to switch between the 3 versions without having to compile different executables (ex. having different library files and loading the "right" one dynamically, don't know if inline functions are "right" for that)? I'd consider also performances in having this kind of switch in the software. There are

I am trying to make the fastest possible high quality RNG. Having read http://xorshift.di.unimi.it/ , xorshift128+ seems like a good option. The C code is #include <stdint.h> uint64_t s[ 2 ]; uint64_t next(void) { uint64_t s1 = s[ 0 ]; const uint64_t s0 = s[ 1 ]; s[ 0 ] = s0; s1 ^= s1 << 23; // a return ( s[ 1 ] = ( s1 ^ s0 ^ ( s1 >> 17 ) ^ ( s0 >> 26 ) ) ) + s0; // b, c } I am not an SSE/AVX expert sadly but my CPU supports SSE4.1 / SSE4.2 / AVX / F16C / FMA3 / XOP instructions. How could you use these to speed up this code (assuming you want to make billions of such random numbers) and what

I'm new to AVX programming. I have a register which needs to be shuffled. I want to shuffle several bytes from a 256-bit register, R1, to an empty register R2. I want to define a mask which tells the shuffle operation which byte from the old register(R1) should be copied at which place in the new register. The mask should look like this(Src:Byte Pos in R1, Target:Byte Pos in R2): {(0,0),(1,1),(1,4),(2,5),...} This means several bytes are copied twice. I'm not 100% sure which function I should use for this. I tried a bit with these two AVX functions, the second just uses 2 lanes. __m256 _mm256