Swizzle format:

| 7:6 | 5:4 | 3:2 | 1:0 |
| --- | --- | --- | --- |
|   w |   z |   y |   x |

16 bit format:

| SwzCAM | (15..13) | (12..8)  | (7..0)|
| ------ | -        | -        | ----- | 
| 0      | rsvd0    | regidx0  | swiz0 |
| 1      | rsvd1    | regidx1  | swiz1 |
| 2      | rsvd2    | regidx2  | swiz2 |
| 3      | rsvd3    | regidx3  | swiz3 |