1
0
Commit Graph

15 Commits

Author SHA1 Message Date
Andrew Waterman
d0c6cbba6b Improve frontend branch prediction
- 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.
2017-11-09 00:00:56 -08:00
Andrew Waterman
989eeb78f9 Prevent some unnecessary pipeline replays 2017-11-06 11:04:06 -08:00
Andrew Waterman
4d6d6ff641 Add instruction-trace port 2017-09-19 22:59:57 -07:00
Andrew Waterman
0a591c5b5b Roll back use of UIntToOH1 (#946)
These appear to be equivalent, but the old one seems to fail in Vivado and
this one seems to pass.  This is not yet conclusive.
2017-08-09 18:39:47 -07:00
Andrew Waterman
721770244e Fix IBuf bug
Don't examine a packet's xcpt signal if it might be invalid.  In this case,
the correct fix is to not examine xcpt at all; the deleted code was vestigial.
(Note, the other use of xcpt(j+1) in this code is indeed safe.)
2017-08-09 09:47:51 -07:00
Palmer Dabbelt
fc0d5fcf98 Print out the compressed instruction when executing one 2017-08-07 17:21:53 -07:00
Andrew Waterman
df7f09b9ce Get I$ ECC check further off critical path 2017-08-04 16:59:21 -07:00
Andrew Waterman
ecc2ee366c Shave a few gate delays off IBuf control logic
It takes a while for the pipeline to compute the stall signal, so avoid
using it until the last logic levels in the clock cycle.
2017-08-04 13:12:43 -07:00
Henry Cook
4c595d175c Refactor package hierarchy and remove legacy bus protocol implementations (#845)
* Refactors package hierarchy.

Additionally:
  - Removes legacy ground tests and configs
  - Removes legacy bus protocol implementations
  - Removes NTiles
  - Adds devices package
  - Adds more functions to util package
2017-07-07 10:48:16 -07:00
Andrew Waterman
3e04a99f61 Refactor frontend exception passing
Bundle them, and leverage regularity, so that if we have to add more
exceptions in the future, we don't need to change so much code.
2017-06-28 02:09:18 -07:00
Andrew Waterman
d24d8ff84b Don't stall the frontend, making it easier to add more features later 2017-04-24 02:01:15 -07:00
Andrew Waterman
069858a20c rocket: separate page faults from physical memory access exceptions 2017-03-27 16:37:09 -07:00
Andrew Waterman
24a2278fc4 Perform all illegal-instruction detection in ID stage
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.
2017-03-09 11:29:51 -08:00
Andrew Waterman
74d8d672bf Improve BTB critical path at slight accuracy cost
Make entries fully associative on lower 14 bits only, not full address.
2017-03-09 11:29:51 -08:00
Henry Cook
e8c8d2af71 Heterogeneous Tiles (#550)
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
2017-02-09 13:59:09 -08:00