Superpages create the possibility that two entries in the TLB may match.
This corresponds to a software bug, but we can't return complete garbage;
we must return either the old translation or the new translation. This
isn't compatible with the Mux1H approach. So, flush the TLB and report
a miss on duplicate entries.
This is simpler, reduces what would have become a critical path in
the commit stage, and will make it easier to support the mbadinst
CSR if it is implemented.
We were zero-extending it, which is a double-precision zero in the recoded
format. So, when spilled and reloaded with fsd/fld, the original value
was destroyed. Instead, set the MSBs so that it represents sNaN. When
spilled, the single-precision number will be preserved as the NaN payload.
- Make API more idiomatic (x holdUnless y, instead of holdUnless(x, y))
- Add new SeqMem API, readAndHold, which corresponds to most common
use of holdUnless
This makes it possible for the bundles to have different widths.
Previously, we had to widen all the bundles passing through a node
to the widest of all the possibilities. This would mean that if
you had two source[] fields, they end up the same.
In order to ensure that verilator is happy, we launch both clocks from a
clock divider. Sadly, it does not follow the spec wrt. derived clocks.
See the verilator manual section on "Generated Clocks".
Doing this in Chisel leads to non-determinism due to shitty
Verilog ordering semantis. Using an '=' ensures that all of
the clock posedges fire before concurrent register updates.
See "Gotcha 29: Sequential logic that requires blocking assignments"
in "Verilog and SystemVerilog Gotchas" by Stuart Sutherland, Don Mills.
VCS is not free. Neither is the vcd format.
Fortunately, verilator and gtkwave ARE free ... and faster too.
This patch adds targets:
run-regression-tests-fst
run-asm-tests-fst
... which create opensource-compatible fst waveforms for gtkwave.
Fundamental new features:
* Added tile package: This package is intended to hold components re-usable across different types of tile. Will be the future location of TL2-RoCC accelerators and new diplomatic versions of intra-tile interfaces.
* Adopted [ModuleName]Params convention: Code base was very inconsistent about what to name case classes that provide parameters to modules. Settled on calling them [ModuleName]Params to distinguish them from config.Parameters and config.Config. So far applied mostly only to case classes defined within rocket and tile.
* Defined RocketTileParams: A nested case class containing case classes for all the components of a tile (L1 caches and core). Allows all such parameters to vary per-tile.
* Defined RocketCoreParams: All the parameters that can be varied per-core.
* Defined L1CacheParams: A trait defining the parameters common to L1 caches, made concrete in different derived case classes.
* Defined RocketTilesKey: A sequence of RocketTileParams, one for every tile to be created.
* Provided HeterogeneousDualCoreConfig: An example of making a heterogeneous chip with two cores, one big and one little.
* Changes to legacy code: ReplacementPolicy moved to package util. L1Metadata moved to package tile. Legacy L2 cache agent removed because it can no longer share the metadata array implementation with the L1. Legacy GroundTests on life support.
Additional changes that got rolled in along the way:
* rocket: Fix critical path through BTB for I$ index bits > pgIdxBits
* coreplex: tiles connected via :=*
* groundtest: updated to use TileParams
* tilelink: cache cork requirements are relaxed to allow more cacheless masters
We want to keep the banks split in the outer SoC if there is an L3.
Furthermore, each channel might go to different memory subsystems,
like DDR/HMC/Zero, from rocketchip.
