**Impact on processor**:
```
- Addition of four new GPR-based instructions
+ Addition of five new GPR-based instructions
```
**Impact on software**:
**Notes and Observations**:
-TODO: address Jacob's comments: https://libre-soc.org/irclog/%23libre-soc.2022-10-28.log.html#t2022-10-28T18:00:27
-
-1. It is not practical to add Rc=1 variants as VA-Form is used and
+1. It is not practical to add Rc=1 variants when VA-Form is used and
there is a **pair** of results produced.
2. An overflow variant (XER.OV set) of `divmod2du` would be valuable
but VA-Form EXT004 is under severe pressure.
3. Both `maddhdu` and `divmod2du` instructions have been present in Intel x86
- for several decades. Likewise, variants of `dsld` and `dsrd`.
+ for several decades. Likewise, `dsld` and `dsrd`.
4. None of these instruction is present in VSX: these are 128/64 whereas
VSX is 128/128.
5. `maddedu` and `divmod2du` are full inverses of each other, including
6. These are all 3-in 2-out instructions. If Power ISA did not already
have LD/ST-with-update instructions and instructions with `RAp`
and `RTp` then these instructions would not be proposed.
-7. `maddedus` is the first scalar signed/unsigned multiply instruction, the
- only other signed/unsigned multiply instruction is `vmsummbm`, which has the
- drawbacks that it is rather specialist, only working on bytes,
- requires VSX/VMX, and isn't very suited for big-integer multiplication or
- other general integer arithmetic.
+7. `maddedus` is the first Scalar signed/unsigned multiply instruction. The
+ only other signed/unsigned multiply instruction is the
+ specialist `vmsummbm` (bytes only), requires VSX,
+ and is unsuited for big-integer or other general arithmetic.
**Changes**