This means FetchStage should now behave in the same way with RVFI-DII as
with an I-Cache. A Dii_Parcel_Id is fed alongside PC everywhere relevant
and follows very similar logic, but, importantly it's just extra state
on the side, it doesn't affect what we do with the branch predictor and
parcel combining/instruction decoding logic.
In particular, the previous set of debug info only looked at one of the
superscalar ways, assuming the 0th was always the next instruction, but
there's a level of indirection to map ports to ways that was missed. But
now we dump out both ways and more. And yes, I fully recognise the
atrocity that is the type in use here... please forgive me. It doesn't
help that bsc is buggy and gets confused about the structure of nested
tuples[1].
Drops the commit debug output to only the low 32 bits of PCC's address
and no instruction bits; as this has been committed it should be (and
has always been observed to be) within bounds and, thus, fit in 32 bits
when running in M-mode, with the instruction bits obtainable from the
binary. I'd much rather know about potentially-dodgy speculative
addresses than things we can reliably infer given the limited number of
DMI registers free (though we could hijack other encodings if
necessary).
[1] https://github.com/B-Lang-org/bsc/issues/199
When DEBUG_WEDGE is defined, expose the last committed and next in the
reorder buffer PC and corresponding instruction via DMI registers, since
even when the core is wedged and we can't read GPRs etc we can still
interact with the debug module itself. Hopefully this proves useful for
debugging wedges.
Now able to run multiple ISA tests in a single simulation run
connected to remote debugger DSharp, using either hart_reset or
ndm_reset between tests to bring the system back into reset state.
All Debug Module commands working:
- dm_reset, hart_reset, ndm_reset
- break (set breakpoint)
- step
- continue (until breakpoint of 'halt' command)
- halt
- read/write GPR, FPR, CSR, memory
- elf_load
After a test, GDB can write DCSR to restore to Machine privilege,
write to PC (DPC) to restore boot value,
write MSTATUS to restore to initial value,
then can load and run next test.
Stop, set breakpoint: working, stopping successfully.
Step: working: stops after a step.
Continue (resume) working after Stop and Step, but not after stop by breakpoint (needs debugging)
Read/Write GPRs, FPRs, CSRs, memory working.
New method 'debug_external_interrupt_req' to support emulation of a
debug module starts at P3_Core interface and is plumbed all the way in
to the CSR register MIP as interrupt [14]. The corresponding MIE[14]
is always 1, so it is never masked. Still todo: should not be masked
by MSTATUS interrupt-enables either. Also expanded
interrupt-detection logic, mcause etc. to extend up to interrupt 14.
Builds in standalone mode, runs ISA tests.
Builds in src_SSITH_P3, generating RTL.
