Re: missing math functions on powerpc (macppc)?

[Frank Wille <frank%phoenix.owl.de@localhost>]

Martin Husemann wrote:

> The problem is that the bug is hiding as a pkg one - it would be really
> cool if you could create a small example code that triggers it as well
> and file a toolchain bug with that.

Here it is. A small function without any includes and dependencides. Just
compile the attachment with gcc 4.8.4 nb2 for PowerPC using the options
-maltivec and -O3.

-- 
Frank Wille

typedef unsigned char uint8_t;
typedef unsigned short uint16_t;

void vp9_temporal_filter_apply_c(uint8_t *frame1,
                                 unsigned int stride,
                                 uint8_t *frame2,
                                 unsigned int block_width,
                                 unsigned int block_height,
                                 int strength,
                                 int filter_weight,
                                 unsigned int *accumulator,
                                 uint16_t *count) {
  unsigned int i, j, k;
  int modifier;
  int byte = 0;
  const int rounding = strength > 0 ? 1 << (strength - 1) : 0;

  for (i = 0, k = 0; i < block_height; i++) {
    for (j = 0; j < block_width; j++, k++) {
      int src_byte = frame1[byte];
      int pixel_value = *frame2++;

      modifier   = src_byte - pixel_value;
      // This is an integer approximation of:
      // float coeff = (3.0 * modifer * modifier) / pow(2, strength);
      // modifier =  (int)roundf(coeff > 16 ? 0 : 16-coeff);
      modifier  *= modifier;
      modifier  *= 3;
      modifier  += rounding;
      modifier >>= strength;

      if (modifier > 16)
        modifier = 16;

      modifier = 16 - modifier;
      modifier *= filter_weight;

      count[k] += modifier;
      accumulator[k] += modifier * pixel_value;

      byte++;
    }

    byte += stride - block_width;
  }
}