Given the following usage:
```
uint32_t mac_result[4];
...
/* MAC calculation here */
...
/* read MAC results */
mac_result[0] = ASM->CBC_MAC_0;
mac_result[1] = ASM->CBC_MAC_1;
mac_result[2] = ASM->CBC_MAC_2;
mac_result[3] = ASM->CBC_MAC_3;
...
```
it is save.
Or did you mean something different?