In Rocket, debug triggers are supposed to happen before a store
occurs, rather than after. Previously, we reported the exception
on the store's PC, but the store occurred anyway. This probably
hasn't been problematic in practice because most stores are
idempotent.
- adds a mutable singleton (PlusArgArtefacts) to store information
about Rocket PlusArgs
- adds methods to PlusArgArtefacts to emit C snippets that are
consumed by emulator.cc for correct argument parsing and help text
generation
- emits snippets in $(CONFIG).plusArgs via BaseCoreplex-set
ElaborationArtefacts
- modify emulator/Makefrag-verilator to include $(CONFIG).plusArgs
- cleanup help text (docstring) for existing PlusArgs
Signed-off-by: Schuyler Eldridge <schuyler.eldridge@gmail.com>
- Put correctness responsibility on Frontend, not IBuf, for improved
separation of concerns. Frontend must detect case that the BTB
predicts a taken branch in the middle of an instruction.
- Pass BTB information down pipeline unconditionally, fixing case that
screws up the branch history when the BTB misses and the instruction
is misaligned.
- Remove jumpInFrontend option; it's now unconditional.
- Default to one-bit counters in the BHT. For tiny BHTs like these, it's
more resource efficient to have a larger index space than to have
hysteresis.
* CSR provides a decode port to check for an illegal instruction.
* This commit now allows for multiple instructions in decode to get this
illegal instruction information.
* This commit leverages the existing decodeWidth parameter. This will
potentially over-provision the number of decode ports needed for
RVC-enabled cores.
Closes#1068
We were using it to compute the next PC on flush vs. replay (which require
PC+4 and PC, respectively). This fix gets rid of the adder altogether by
reusing the M-stage PC in the flush case, which by construction holds PC+4.
Andrew Waterman
Henry Cook
Schuyler Eldridge
Richard Xia
Christopher Celio
Andrew Waterman
Megan Wachs
Palmer Dabbelt