BLOCK_MASK
set_block(&diff_a_head, x, ch | BLOCK_MASK);
set_block(&diff_a_head, x, ch | BLOCK_MASK);
set_block(&diff_a_head, x + 1, chn | BLOCK_MASK);
set_block(&diff_a_head, x, ch | BLOCK_MASK);
set_block(&diff_a_head, x, ch | BLOCK_MASK);
set_block(&diff_a_head, x + 1, chn | BLOCK_MASK);
set_block(&diff_a_head, x, ch | BLOCK_MASK);
set_block(&diff_a_head, x + 1, chn | BLOCK_MASK);
set_block(&diff_a_head, x, ch | BLOCK_MASK);
if (ch & BLOCK_MASK)
set_block(&diff_a_head, x, ch | BLOCK_MASK);
if (ch & BLOCK_MASK)
set_block(&diff_a_head, x, ch | BLOCK_MASK);
set_block(&diff_a_head, x, ch | BLOCK_MASK);
set_block(&diff_a_head, x, ch | BLOCK_MASK);
if (ch & BLOCK_MASK)
set_block(&diff_a_head, x, ch | BLOCK_MASK);
if (ch & BLOCK_MASK)
set_block(&diff_a_head, x, ch | BLOCK_MASK);
if (y1 > x && !(ch & (BLOCK_MASK | BLOCK_ADD)))
} else if (!(ch & BLOCK_MASK)) {
block_compress = maxbits & BLOCK_MASK;
block_compress = BLOCK_MASK;
zs->zs_block_compress = BLOCK_MASK;
zs->zs_block_compress = zs->zs_maxbits & BLOCK_MASK;