fb_read_offset
d0 = fb_left(reorder(fb_read_offset(-1, src), reverse), left);
d0 |= fb_right(reorder(fb_read_offset(0, src), reverse), right);
d0 = fb_right(reorder(fb_read_offset(0, src), reverse), right);
d0 = reorder(fb_read_offset(-1, src), reverse);
d1 = reorder(fb_read_offset(0, src), reverse);
d1 = fb_read_offset(offset + 0, src);
d1 = fb_read_offset(offset + 1, src);
d1 = fb_read_offset(offset + 2, src);
d1 = fb_read_offset(offset + 3, src);
d1 = reorder(fb_read_offset(offset, src), reverse);
d0 |= fb_right(reorder(fb_read_offset(offset, src), reverse),
d0 = fb_right(reorder(fb_read_offset(1, src), reverse), right);
d0 |= fb_left(reorder(fb_read_offset(0, src), reverse), left);
d0 = fb_left(reorder(fb_read_offset(0, src), reverse), left);
d0 |= fb_right(reorder(fb_read_offset(1, src), reverse), right);
d0 = fb_right(reorder(fb_read_offset(end + 1, src), reverse), right);
d1 = reorder(fb_read_offset(end, src), reverse);
d1 = fb_read_offset(end - 1, src);
d1 = fb_read_offset(end - 2, src);
d1 = fb_read_offset(end - 3, src);
d1 = fb_read_offset(end - 4, src);
d1 = reorder(fb_read_offset(end, src), reverse);
d0 |= fb_left(reorder(fb_read_offset(0, src), reverse), left);
fb_modify_offset(fb_read_offset(offset, src), mask, offset, dst);
fb_write_offset(fb_read_offset(offset, src), offset, dst);
fb_write_offset(fb_comp(val, fb_read_offset(offset, dst), mask), offset, dst);
fb_write_offset(fb_read_offset(offset, dst) ^ pat, offset, dst);
old = fb_read_offset(0, dst);
old = fb_read_offset(offset, dst);