The table for [[sv/svp64]] for `immed(RA)` which is `RM.MODE`
(bits 19:23 of `RM`) is:
-| 0-1 | 2 | 3 4 | description |
-| --- | --- |---------|--------------------------- |
-| 00 | 0 | zz els | simple mode |
-| 00 | 1 | PI LF | post-increment and Fault-First |
-| 01 | inv | CR-bit | Rc=1: ffirst CR sel |
-| 01 | inv | els RC1 | Rc=0: ffirst z/nonz |
-| 10 | N | zz els | sat mode: N=0/1 u/s |
-| 11 | inv | CR-bit | Rc=1: pred-result CR sel |
-| 11 | inv | els RC1 | Rc=0: pred-result z/nonz |
+| 0 | 1 | 2 | 3 4 | description |
+|---|---| --- |---------|--------------------------- |
+| 0 | 0 | 0 | zz els | simple mode |
+| 0 | 0 | 1 | PI LF | post-increment and Fault-First |
+| 1 | 0 | N | zz els | sat mode: N=0/1 u/s |
+|VLi| 1 | inv | CR-bit | Rc=1: ffirst CR sel |
+|VLi| 1 | inv | els RC1 | Rc=0: ffirst z/nonz |
+
The `els` bit is only relevant when `RA.isvec` is clear: this indicates
whether stride is unit or element:
The modes for `RA+RB` indexed version are slightly different
but are the same `RM.MODE` bits (19:23 of `RM`):
-| 0-1 | 2 | 3 4 | description |
-| --- | --- |---------|-------------------------- |
-| 00 | SEA | dz sz | simple mode |
-| 01 | SEA | dz sz | Strided (scalar only source) |
-| 10 | N | dz sz | sat mode: N=0/1 u/s |
-| 11 | inv | CR-bit | Rc=1: pred-result CR sel |
-| 11 | inv | zz RC1 | Rc=0: pred-result z/nonz |
+| 0 | 1 | 2 | 3 4 | description |
+|---|---| --- |---------|--------------------------- |
+|els| 0 | SEA | dz sz | simple mode |
+|VLi| 1 | inv | CR-bit | Rc=1: ffirst CR sel |
+|VLi| 1 | inv | els RC1 | Rc=0: ffirst z/nonz |
Vector Indexed Strided Mode is qualified as follows:
```
- if mode = 0b01 and !RA.isvec and !RB.isvec:
+ if els and !RA.isvec and !RB.isvec:
svctx.ldstmode = elementstride
```