* 32-bit opcode prefix takes 7 bits, therefore 10 bits remain to fit
a SVPrefix.
* compared to P48, 11 bits are needed.
-* however, with the exception of LD/ST these all provide *three* operands:
- rs1, rs2 and rs3.
+* however, with the exception of LD/ST (and C.MV) these all provide *three*
+ operands: rs1, rs2 and rs3.
* therefore, 1 field can go, and that just leaves what to do with LD/ST
+ and C.MV
* should twin-predication be sacrificed?
* should one of the vectorisation modes be sacrificed?
* is there room in ohe of the other "MAJOR CUSTOM OPCODEs" (0,1) to
fit the "other" mode somehow?
* can one of the vew bits be sacrificed instead, reducing vitp7 by 1 bit?
+P48:
+
+---------------+--------+--------+----------+-----+--------+-------------+------+--------+--------+
| Encoding | 17 | 16 | 15 | 14 | 13 | 12 | 11:7 | 6 | 5:0 |
+---------------+--------+--------+----------+-----+--------+-------------+------+--------+--------+
| P32C-FR4-type | rd[5] | rs1[5] | rs2[5] | vs2 | rs3[5] | vs3 [#fr4]_ | vtp5 | *Rsvd* | 011111 |
+---------------+--------+--------+----------+-----+--------+-------------+------+--------+--------+
+P32C:
+
++---------------+--------+--------+----------+--------+-------------+------+--------+--------+
+| Encoding | 17 | 16 | 15 | 13 | 12 | 11:7 | 6 | 5:0 |
++---------------+--------+--------+----------+--------+-------------+------+--------+--------+
+| P32C-CL-type | rd[5] | rs1[5] | vitp7[6] | vs1 | vitp7[5:0] | *Rsvd* | 011111 |
++---------------+--------+--------+----------+--------+--------------------+--------+--------+
+| P32C-CS-type |vitp7[6]| rs1[5] | rs2[5] | vs1 | vitp7[5:0] | *Rsvd* | 011111 |
++---------------+--------+--------+----------+--------+-------------+------+--------+--------+
+| P32C-FR-type | rd[5] | rs1[5] | rs2[5] | vs1 | *Rsvd* | vtp5 | *Rsvd* | 011111 |
++---------------+--------+--------+----------+--------+-------------+------+--------+--------+
+| P32C-FR-type | rd[5] | rs1[5] | rs2[5] | vs1 | *Rsvd* | vtp5 | *Rsvd* | 011111 |
++---------------+--------+--------+----------+--------+-------------+------+--------+--------+
+| P32C-CR-type | rd[5] | rs1[5] | rs2[5] | vs1 | vitp6 | *Rsvd* | 011111 |
++---------------+--------+--------+----------+--------+--------------------+--------+--------+
+| P32C-CA-type | rd[5] | rs1[5] | vitp7[6] | vs1 | vitp7[5:0] | *Rsvd* | 011111 |
++---------------+--------+--------+----------+--------+--------------------+--------+--------+
+| P32C-CU-type | rd[5] | *Rsvd* | *Rsvd* | *Rsvd* | vitp6 | *Rsvd* | 011111 |
++---------------+--------+--------+----------+--------+--------------------+--------+--------+
+
Questions
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