SVP64 RM `MODE` (includes `ELWIDTH_SRC` bits) for CR-based operations:
| 6 | 7 | 19-20 | 21 | 22 23 | description |
-| - | - | ----- | --- |---------|----------------- |
+| - | - |-------| --- |---------|----------------- |
|sz |SNZ| 0 RG | 0 | dz / | normal mode |
|sz |SNZ| 0 RG | 1 | 0 / | scalar reduce mode (mapreduce), SUBVL=1 |
|zz |SNZ| 0 RG | 1 | 1 / | parallel reduce mode (mapreduce), SUBVL=1 |