On 2021/8/12 下午2:12, Richard Henderson wrote:
On 8/11/21 7:03 PM, LIU Zhiwei wrote:
On 2021/8/12 下午12:42, Richard Henderson wrote:
On 8/11/21 12:40 PM, LIU Zhiwei wrote:
If the software doesn't use the high part, who cares the really
value in high part? Do you know the benefit? Thanks again.
I do not.
I simply presume that they already have the hardware, in the form of
the addw instruction, etc.
The mistake, I think, was changing the definition of "add" in the
first place, which required the addition of a different opcode
"addw", which is then undefined for RV32.
Sorry, I don't get "the mistake" here. Do you think the specification
is not right.
I was critiquing the development of the risc-v specification, in that
there are complications in the current specification that could have
been foreseen and avoided with different choices years ago.
They should simply have had "addw" and "addq" as different opcodes
that didn't change behaviour. Etc.
I don't get this statement. Is it related to UXL32?
No. I was just musing. It's not important.
Although I don't know what really you mean, I think "addw" and "addq"
will be better than current "addw" and "add".
At least we can avoid adjust almost every instruction like "add" for UXL32.
Best Regards,
Zhiwei
r~
