Again it is the 24 bit `RM` that is interpreted differently:
-| 0...4 | 5.7 | 8 | 10 | 12 | 14 | 16 | 18..23 |
-| ----- | --- | -- | -- | -- | -- | -- | ------ |
-| en0-4 | rsv |mi0 |mi1 |mi2 |mo0 |mo1 | rsv |
-
-The shape indices 0-3 are numbered 0-3 whilst the masks are bitmasks
-that indicate src or dest to which the associated shape (0-3) is to
-be applied. A zero mask indicates that the Shape is not to be applied.
-Note that whilst the masks are unary encoded the Shape indices sh0-3
-are not: this must be taken into consideration when ORing occurs.
-
-The mask is encoded as follows:
-
-* bit 0 indicates that the first svp64 EXTRA field is reshaped
-* bit 1 indicates that the second svp64 EXTRA field is reshaped
-* bit 2 indicates that the third sv64 EXTRA field is reshaped
-* bit 3 indicates that the fourth svp64 EXTRA field reshaped
-
-This allows even instructions that have 2 destination registers to be reshaped.
+| 0 | 2 | 4 | 6 | 8 | 10.14 | 15..23 |
+| -- | -- | -- | -- | -- | ----- | ------ |
+|mi0 |mi1 |mi2 |mo0 |mo1 | en0-4 | rsv |
+
+si0-2 and so0-1 each select SVSHAPE0-3 to apply to a given register.
+si0-2 apply to RA, RB, RC respectively, as input registers, and
+likewise so0-1 apply to output registers. en0-4 indicate whether the
+SVSHAPE is actively applied or not.
# setvl