Previously we were relying on the beat count registers being exactly the
right number of bits such that we'd overflow from 7 back to 0 after the
final flit. This change aligns the LLC adapter with the MMIO adapter,
which already does things in a safer way. We can also just look at rlast
for read respones rather than a full 3-bit comparison (the MMIO adapter
also makes this micro-optimisation).
alignment of the original data.
Also eliminate the call to the reimplementation of the AMO functions.
(One call was already converted to use the common function, and I've now
converted the other.)
It's honestly unknown how much of this works, but it's more likely to
work than what was previously implemented, I think, given that the
previou implementation was based on some basic misconceptions concerning
data alignment.
This incorporates the fix made to Piccolo and Flute to not trap on
C.FLWSP/C.FLDSP when rd == 0; unlike the compressed stack pointer
relative integer loads/stores, these are legal, since f0 is a real FPR
rather than a constant zero.
This incorporates the fix made to Piccolo and Flute to not trap on
C.FLWSP/C.FLDSP when rd == 0; unlike the compressed stack pointer
relative integer loads/stores, these are legal, since f0 is a real FPR
rather than a constant zero.
Otherwise, the next MMIO access will see the 0 from the write response
instead of its response, and every subsequent access will see the
previous's response, further accumulating if more uncached AMOs are
performed.
This required makeing the Exception type wider by one.
The actual "inBounds" check is currently implemented in the reorder buffer rows, which duplicates the logic ~80 times (number of outstanding instructions), which isn't ideal, but it's using the quick in-bounds check that only compares the mantissa-sized things.
This includes renaming Fifo.bsv to Fifos.bsv to account for a case insensitive file system which confuses this library with FIFO.bsv.
Also this includes an update of the verilator flags that are needed for modern verilator.
Finally, some verilator flag changes for building with LLVM.
Two of these were not properly restricted as read-only from CSRRX instructions,
and there was a bug in the WARL function for writing MIP,
and there was a bug in the TV-reporting of MIP updates.
When a CSRRx instruction writes to FCSR/FFLAGS/FRM, the CPU also
changes MSTATUS.FS and, by implication, MSTATUS.SD because the
floating point state has become "dirty". Tandem Verification
trace-generation was not reporting this update.
PLIC: updated to latest version from Piccolo/Flute.
MMIO_AXI4_Adapter: added workaround for Xilinx IP problem on 64-bit
AXI4 fabrics. Writes that specify 8-byte size, but only write in
upper or lower word using strobes, are converted into 4-byte size.
Core.bsv: added a notification to the Debug Module re. CPU halt.
MIP/MIE/SIP/SIE fields are WARL (Write-Any/Read-Legal). The CSR
register forces the user-privilege bits ([8,4,0]) to 0 since riscy-ooo
does not support user-level interrupts. However, function
Csrfile.fv_warl_xform() was not mirroring this correctly.
(1) riscy-ooo was mapping all unimplemented CSRs to a benign, user-privilege read-write CSR
Instead, we now catch this RenameStage and steer it to a trap.
(2) MSTATUS.FS was initialized to 2'b00 (absent/off); should be 2'b01 (present and initial)
