Function xsum_large_transfer_to_small

xs/sources/xsum.c:687–801

/* TRANSFER ALL CHUNKS IN LARGE ACCUMULATOR TO ITS SMALL ACCUMULATOR. */

static void xsum_large_transfer_to_small (xsum_large_accumulator *restrict lacc)
{
  if (xsum_debug) c_printf("\nTRANSFERRING CHUNKS IN LARGE ACCUMULATOR\n");

# if USE_USED_LARGE
  {
    xsum_used *p, *e;
    xsum_used u, uu;
    int ix;

    p = lacc->chunks_used;
    e = p + XSUM_LCHUNKS/64;

    /* Very quickly skip some unused low-order blocks of chunks by looking
       at the used_used flags. */

    uu = lacc->used_used;
    if ((uu & 0xffffffff) == 0)
    { uu >>= 32;
      p += 32;
    }
    if ((uu & 0xffff) == 0)
    { uu >>= 16;
      p += 16;
    }
    if ((uu & 0xff) == 0)
    { p += 8;
    }

    /* Loop over remaining blocks of chunks. */

    do
    {
      /* Loop to quickly find the next non-zero block of used flags, or finish
         up if we've added all the used blocks to the small accumulator. */

      for (;;)
      { u = *p;
        if (u != 0)
        { break;
        }
        p += 1;
        if (p == e)
        { return;
        }
        u = *p;
        if (u != 0)
        { break;
        }
        p += 1;
        if (p == e)
        { return;
        }
        u = *p;
        if (u != 0)
        { break;
        }
        p += 1;