• Janne Grunau's avatar
    ppc: reduce overreads when loading 8 pixels in altivec dsp functions · 98fdfa99
    Janne Grunau authored
    Altivec can only load naturally aligned vectors. To handle possibly
    unaligned data a second vector is loaded from an offset of the original
    location and the data is recovered through a vector permutation.
    Overreads are minimal if the offset for second load points to the last
    element of data. This is 7 for loading eight 8-bit pixels and overreads
    are reduced from 16 bytes to 8 bytes if the pixels are 64-bit aligned.
    For unaligned pixels the overread is reduced from 23 bytes to 15 bytes
    in the worst case.
    98fdfa99
dsputil_altivec.c 37.6 KB