HAMMER_BLOCKMAP_LAYER1_INDEX
HAMMER_BLOCKMAP_LAYER1_INDEX(zone_offset),
HAMMER_BLOCKMAP_LAYER1_INDEX(offset),
HAMMER_BLOCKMAP_LAYER1_INDEX(offset),
i = HAMMER_BLOCKMAP_LAYER1_INDEX(offset);
(HAMMER_BLOCKMAP_LAYER1_INDEX(zone2_offset) * \