Function sseSelect

src/OpenColorIO/SSE.h:149–156

Bit-wise select function in SSE version 2 Return the parameter arg_false bit where the parameter mask is 0x0, return the parameter arg_true bit where the mask is 1. Algorithm Explanation: Uses the identities: x XOR 0 = x x XOR x = 0 select = ((arg_true XOR arg_false) AND mask) XOR arg_false When mask = 0, the expression evaluates to: = ((arg_true XOR arg_false) AND 0x0) XOR arg_false = 0x0 XO

//   solution requires two registers.
//
inline __m128 sseSelect(const __m128& mask, const __m128& arg_true, const __m128& arg_false)
{
    return _mm_xor_ps(                                  // bit-wise XOR of arg_false, (...)
        arg_false, 
        _mm_and_ps(                                     // bit-wise AND of mask, (...)
            mask, 
            _mm_xor_ps( arg_true, arg_false ) ) );      // bit-wise XOR of arg_true, arg_false
}

// Coefficients of Chebyshev (minimax) degree 5 polynomial
// approximation to log2() over the range [1.0, 2.0[.