Hi Frédéric,
you are right, I misunderstood the "LQ is added to the MISC-MEM major
opcode" part of the spec.
I saw the encoding conflict with the CBO instructions and thought of a
bug in qemu's LQ encoding.
Philipp already highlighted that cbo.* instructions are actually LQ with rd=0.
Thanks,
Chr
The cbo.* mnemonics share their opcode space with lq for those cases where
rd == 0 ("brownfield" encodings).
"Major opcode" refers to inst[6:0] according to chapter 26.
In overlapping multi-group syntax, this would look like:
> {
>
> # *** RV32 Zicbom Standard Extension ***
>
> cbo_clean 000
Le 18/01/2022 à 17:32, Christoph Muellner a écrit :
If LQ has func3==010 and is located in the MISC-MEM opcodes,
then it conflicts with the CBO opcode space.
However, since LQ is specified as: "LQ is added to the MISC-MEM major
opcode", we have an implementation bug, because 'major opcode'
refers
If LQ has func3==010 and is located in the MISC-MEM opcodes,
then it conflicts with the CBO opcode space.
However, since LQ is specified as: "LQ is added to the MISC-MEM major
opcode", we have an implementation bug, because 'major opcode'
refers to func3, which must be 111.
This results in the fol
