void SelectColumnsOfB()

in gemmology.h [1007:1027]

• 20 lines of code
• 5 McCabe index (conditional complexity)

void SelectColumnsOfB(const xsimd::batch<int8_t, Arch> *input,
                      xsimd::batch<int8_t, Arch> *output,
                      size_t rows_bytes /* number of bytes in a row */,
                      const IntegerTy *cols_begin, const IntegerTy *cols_end) {
  using batch8 = xsimd::batch<int8_t, Arch>;
  /* Do columns for multiples of 8.*/
  size_t register_rows = rows_bytes / batch8::size;
  const batch8 *starts[8];
  for (; cols_begin != cols_end; cols_begin += 8) {
    for (size_t k = 0; k < 8; ++k) {
      starts[k] =
          input + (cols_begin[k] & 7) + (cols_begin[k] & ~7) * register_rows;
    }
    for (size_t r = 0; r < register_rows; ++r) {
      for (size_t k = 0; k < 8; ++k) {
        *(output++) = *starts[k];
        starts[k] += 8;
      }
    }
  }
}