On Mon, Mar 7, 2022 at 3:53 PM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: > diff --git a/tests/util/pattern.c b/tests/util/pattern.c > index 953bf95492ee150c..42d75d700700dc3d 100644 > --- a/tests/util/pattern.c > +++ b/tests/util/pattern.c > @@ -608,6 +608,46 @@ static void fill_smpte_rgb16fp(const struct util_rgb_info *rgb, void *mem, > static unsigned int smpte_middle[7] = { 6, 7, 4, 7, 2, 7, 0 }; > static unsigned int smpte_bottom[8] = { 8, 9, 10, 7, 11, 7, 12, 7 }; > > +static void write_pixel_4(uint8_t *mem, unsigned int x, unsigned int pixel) > +{ > + if (x & 1) > + mem[x / 2] = (mem[x / 2] & 0xf0) | (pixel & 0x0f); > + else > + mem[x / 2] = (mem[x / 2] & 0x0f) | (pixel << 4); > +} The standard layout is MSB? i.e. first pixel goes in the upper bits of the first byte? It's been ages since I've dealt with C4 (or perhaps I never even touched it), but this seems a bit surprising.