Moved committedInsts from O3 cpu.* to BaseCPU as numInstsNotNOP because
it tracks the instructions committed that are not NOPs or prefetches.
This change also does the same for commitedOps. InstsCommitted from O3
commit.*, which tracks all instructions committed, has been removed.
CommitCPUStats::numInsts replaces it in O3. The same has been done for
opsCommitted. Because IPC and CPI calculations are handled in BaseCPU,
removed IPC and CPI stats from O3 cpu.*.
Change-Id: I9f122c9a9dafccd5342f18056f282f3dad8b1b1e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67393
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
In BaseCPU::BaseCPUStats, numInsts and numOps track per CPU core
committed instructions and operations.
In BaseCPU::FetchCPUStats, numInsts and numOps track per thread
fetched instructions and operations.
In BaseCPU::CommitCPUStats, numInsts and numOps track per thread
committed instructions and operations.
In BaseSimpleCPU, the countInst() function has been split into
countInst(), countFetchInst(), and countCommitInst(). The stat count
incrementation of countInst() has been removed and delegated to the
other two functions. countFetchInst() increments numInsts and numOps
of the FetchCPUStats group for a thread. countCommitInst() increments
the numInsts and numOps of the CommitCPUStats group for a thread and
of the BaseCPUStats group for a CPU core. These functions are called
in the appropriate stage within timing.cc and atomic.cc. The call to
countInst() is left unchanged. countFetchInst() is called in
preExecute(). countCommitInst() is called in postExecute().
For MinorCPU, only the commit level numInsts and numOps stats have been
implemented.
IPC and CPI stats have been added to BaseCPUStats (core level) and
CommitCPUStats (thread level). The formulas for the IPC and CPI stats
in CommitCPUStats are set in the BaseCPU constructor, after the
CommitCPUStats stat group object has been created.
Change-Id: If893b331fe4a6908e4b4caf4a30f1b0aeb4c4266
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67392
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Created stat group CommitCPUStats in BaseCPU and moved stats from the
simple cpu model.
The stats moved from SImpleCPU are numCondCtrlInsts, numFpInsts,
numIntInsts, numLoadInsts, numStoreInsts, numVecInsts.
Moved committedControl of MinorCPU to BaseCPU::CommittedCPUStats. In
MinorCPU, this stat was a 2D vector, where the first dimension is the
thread ID. In base it is now a 1D vector that is tied to a thread ID
via the commitStats vector.
The committedControl stat vector in CommitCPUStats is updated in the
same way in all CPU models. The function updateComCtrlStats will
update committedControl and the CPU models will call this function
instead of updating committedControl directly. This function takes
a StaticInstPtr as input, which Simple, Minor, and O3 CPU models are
able to provide.
Removed stat "branches" from O3 commit stage. This stat duplicates
BaseCPU::CommittedCPUStats::committedControl::IsControl.
O3 commit stats floating, integer, loads, memRefs, vectorInstructions
are replaced by numFpInsts, numIntInsts, numLoadInsts, numMemRefs,
numVecInsts from BaseCPU::CommitCPUStats respectively. Implemented
numStoreInsts from BaseCPU::commitCPUStats for O3 commit stage.
Change-Id: I362cec51513a404de56a02b450d7663327be20f5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67391
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Created stat group ExecuteCPUStats in BaseCPU and moved stats from the
simple and minor cpu models.
The stats moved from SimpleCPU are dcacheStallCycles,
icacheStallCycles, numCCRegReads, numCCRegWrites, numFpAluAccesses,
numFpRegReads, numFpRegWrites, numIntAluAccesses, numIntRegReads,
numIntRegWrites, numMemRefs, numMiscRegReads, numMiscRegWrites,
numVecAluAccesses, numVecPredRegReads, numVecPredRegWrites,
numVecRegReads, numVecRegWrites.
The stat moved from MinorCPU is numDiscardedOps.
Also, ccRegfileReads, ccRegfileWrites, fpRegfileReads, fpRegfileWrites,
intRegfileReads, intRegfileWrites, miscRegfileReads, miscRegfileWrites,
vecPredRegfileReads, vecPredRegfileWrites, vecRegfileReads,
and vecRegfileWrites are removed from cpu.hh and cpu.cc in O3CPU. The
corresponding stats in BaseCPU::ExecuteCPUStats are used instead.
Changed the getReg, getWritableReg, and setReg functions in the O3 CPU
object to take the thread ID as a parameter. This is because the stats
in base are stored in vectors that are indexed by thread ID.
Change-Id: I801c5ceb4c70b7b281127569f11c6ee98f614b27
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67390
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
This summarizes a series of changes to move general Simple, Minor,
O3 CPU stats to BaseCPU. This commit focuses on moving numBranches
from SimpleCPU to the FetchCPUStats in the BaseCPU, and
numFetchSuspends from MinorCPU into FetchCPUStats. More general
information about this relation chain is below
1. Summary:
Moved general CPU stats found across Simple, Minor, and O3 CPU models
into BaseCPU through new stat groups. The stat groups are
FetchCPUStats, ExecuteCPUStats, and CommitCPUStats. Implemented the
committedControl stat vector found in MinorCPU for Simple and O3 CPU.
Implemented the numStoreInsts stat found in SimpleCPU for O3CPU. IPC
and CPI stats are now tracked at the core and thread level in BaseCPU
and are made universal for simple, minor, o3, and kvm CPUs. Duplicate
stats across the models are merged into a single stat in BaseCPU under
the same stat name. This change does not implement every general level
stat moved to BaseCPU for every model.
2. Stat API Changes
a. SimpleCPU:
statExecutedInstType vector unified into committedInstType
numCondCtrlInsts unified into committedControl::isControl
b. O3CPU:
i. Fetch Stage
branches in fetch unified into with numBranches
rate renamed to fetchRate
insts unified into with numInsts
ii. Execute Stage
Regfile stats unified into base with use of Simple's stat naming
numRefs in IEW unified into numMemRefs
numRate from IEW renamed to instRate
iii. Commit Stage
committedInsts is renamed to numInstsNotNOP
committedOps is renamed to numOpsNotNOP
instsCommitted is unified into numInsts
opsCommitted is unified into numOps
branches is unified into committedControl::isControl
floating is unified into numFpInsts
integer is unified into numIntInsts
loads is unified into numLoadInsts
memRefs is renamed to numMemRefs
vectorInstructions is unified into numVecInsts
3. Details:
Created three stat groups in BaseCPU. FetchCPUStats track statistics
related to the fetch stage. ExecuteCPUStats track statistics related
to the execute stage. CommitCPUStats track statistics related to the
commit stage.
There are three vectors in Base that store unique pointers to per
thread instances of these stat groups. The stat group pointer for
thread i is accessible at index i of one of these vectors. For example,
stat numCCRegReads of the execute stage for thread 0 can be accessed
with executeStats[0]->numCCRegReads. The stats.txt output will print the
thread ID of the stat group. For example, numVecRegReads on thread 0
of a single core prints as
"board.processor.cores.core.executeStats0.numVecRegReads".
NOTE: Multithreading in gem5 is untested. Therefore per thread stats
output in stats.txt is not currently guaranteed to be correctly
formatted.
For FetchCPUStats, the stats moved from SimpleCPU are numBranches
and numInsts. From MinorCPU, the stat moved is numFetchSuspends. From
O3CPU, the stats moved are from the O3 fetch stage: Stat branches is
unified into numBranches, stat rate is renamed to fetchRate in Base,
stat insts is unified into numInsts, stat icacheStallCycles keeps the
same name in Base.
For ExecuteCPUStats, the stats moved from SimpleCPU are
dcacheStallCycles, numCCRegReads, numCCRegWrites,
numFpAluAccesses, numFpRegReads, numFpRegWrites, numIntAluAccesses,
numIntRegReads, numIntRegWrites, numMemRefs, numMiscRegReads,
numMiscRegWrites, numVecAluAccesses, numVecPredRegReads,
numVecPredRegWrites, numVecRegReads, numVecRegWrites. The stat moved
from MinorCPU is numDiscardedOps. From O3, the Regfile stats in CPU are
unified into the reg stats in Base and use the names found originally
in SimpleCPU. From O3 IEW stage, numInsts keeps the same name in
Base, numBranches is unified into numBranches in base, numNop keeps
the same name in Base, numRefs is unified into numMemRefs in Base,
numLoadInsts and numStoreInsts are moved into Base, numRate is renamed
to instRate in base.
For CommitCPUStats, the stats moved from SimpleCPU are
numCondCtrlInsts, numFpInsts, numIntInsts, numLoadInsts, numStoreInsts,
numVecInsts. The stats moved from MinorCPU are numInsts,
committedInstType, and committedControl. statExecutedInstType of
SimpleCPU is unified with committedInstType of MinorCPU. Implemented
committedControl stats from MinorCPU in Simple and O3 CPU. In MinorCPU,
this stat was a 2D vector, where the first dimension is the thread ID.
In base it is now a 1D vector that is tied to a thread ID via the
commitStats vector that the object is accessible through. From the O3
commit stage, committedInsts is renamed to numInstsNotNOP, committedOps
is renamed to numOpsNotNOP, instsCommitted is unified into numInsts,
opsCommitted is renamed to numOps, committedInstType is unified into
committedInstType from Minor, branches is removed because it duplicates
committedControl::IsControl, floating is unified into numFpInsts,
interger is unified into numIntInsts, loads is unified into
numLoadInsts, numStoreInsts is implemented for tracking in O3, memRefs
is renamed to numMemRefs, vectorInstructions is unified into
numVecInsts. Note that numCondCtrlInsts of Simple is unified into
committedControl::IsCondCtrl.
Implemented IPC and CPI tracking inside BaseCPU.
In BaseCPU::BaseCPUStats, numInsts and numOps track per CPU core
committed instructions and operations.
In BaseCPU::FetchCPUStats, numInsts and numOps track per thread
fetched instructions and operations.
In BaseCPU::CommitCPUStats, numInsts tracks per thread executed
instructions.
In BaseCPU::CommitCPUStats, numInsts and numOps track per thread
committed instructions and operations.
In BaseSimpleCPU, the countInst() function has been split into
countInst(), countFetchInst(), and countCommitInst(). The stat count
incrementation step of countInst() has been removed and delegated to the
other two functions. countFetchInst() increments numInsts and numOps
of the FetchCPUStats group for a thread. countCommitInst() increments
the numInsts and numOps of the CommitCPUStats group for a thread and
of the BaseCPUStats group for a CPU core. These functions are called
in the appropriate stage within timing.cc and atomic.cc. The call to
countInst() is left unchanged. countFetchInst() is called in
preExecute(). countCommitInst() is called in postExecute().
For MinorCPU, only the commit level numInsts and numOps stats have been
implemented.
IPC and CPI stats have been added to BaseCPUStats (core level) and
CommitCPUStats (thread level). The formulas for the IPC and CPI stats
in CommitCPUStats are set in the BaseCPU constructor, after the
CommitCPUStats stat group object has been created. These replace IPC,
CPI, totalIpc, and totalCpi stats in O3.
Replaced committedInsts stats of KVM CPU with commitStats.numInsts
of BaseCPU. This results in IPC and CPI printing in stats.txt for
KVM simulations.
This change does not implement most general stats found in one or two
model for all others.
Jira Ticket: https://gem5.atlassian.net/browse/GEM5-1304
Change-Id: I3c852f8dba3268c71b7a3415480fb63d8dc30cb7
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/66031
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
While the PcCountTracker isn't necessary in the NULL ISA, the
structure of the standard library requires us to have it built
when running the replacement policy tests, which should fix
these tests failing within the nightlies at the moment.
Change-Id: I225b7923f2a11d351c24bdceba3ded4ed2b3bc87
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/68597
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
PcCountTracker is a probelistener that connects to one core and listens
for a list of Program Counter addresses(PCs). It notifys the
PcCountTrackerManager every time it encounters a Program Counter
address in the list.
PcCountTrackerManager is a SimObject that is responsible for keeping
track of a list of PC-count pairs and the number of time a particular
PC has been executed globally.
This patch adds a way to track the number of times a set of specific
PCs have been executed.
Change-Id: I8f47bfa7e29aa2bb6ab817417266033439b85d51
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67194
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
This commit introduces a PcCountPair type that stores a Program Counter
address and an integer of counts for the Program Counter address.
The PcCountPair can be used in the same way and hashable in both C++
and Python.
Change-Id: I66d93e2c6a1d286cb9dd795ba97f8d887f67d503
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67193
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
This port will stop execution on the CPU when raised. When lowered, it
will allow execution to reset the state of the CPU and allow execution
to resume. The state could theoretically be reset when the reset state
starts, but then it wouldn't reflect the most up to date condition of
the CPU when resuming. For instance, if a reset vector was set
somehow, that wouldn't be updated if it was changed while reset was
asserted. The tradeoff is that the state won't look like it will when
execution resumes while reset is held (to GDB for instance), but that
seems like a more obvious and less common sort of problem.
This signal is managed by the BaseCPU itself, but is backed by a
virtual method which can be overridden by other CPU types which may
not work the same way or have the same components. For instance, a
fast model CPU could toggle reset lines on the underlying model and
let it handle resetting all the state.
The fast models in particular already have a generic reset line with
the same name, but they have it at the level of the fast model which
may have multiple cores within it, each represented by a gem5 CPU.
It isn't implemented here, but there could be some sort of cooperation
between these signals where the reset at the core level is considered
an "or" of the cluster level reset and the individual core level
resets. At least in the A76 model, there are resets for each individual
core within the cluster as well, which the generic reset toggles.
Another option would be to get rid of the whole cluster reset pin, and
make the user gang the resets for each of the cores together to
whatever reset signal they're using. That's effectively what the
cluster level reset is doing, but within the C++ of the model wrapper
instead of in the python config.
Change-Id: Ie6b4769298ea224ec5dc88360cbb52ee8fbbf69c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67574
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Roger Chang <rogerycchang@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
The ISA parser now emits the code required to access matrix
registers. In the case where a register is both a source and a
destination, the ISA parser generates appropriate code to make sure
that the contents of the source is copied to the destination. This is
required for the O3 CPU which treats these as two different physical
registers, and hence data is lost if not explicitly preserved.
Jira Issue: https://gem5.atlassian.net/browse/GEM5-1289
Change-Id: I8796bd1ea55b5edf5fb8ab92ef1a6060ccc58fa1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/64338
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Currently the gem5 standard library does not define a class to represent
a cluster of CPUs.
The SubSystem class has been extended in some python modules [1] to
define clock/voltage domains shared by a group of CPUs (the cluster),
and to provide some utility functions for top level configs.
This patch is moving the aforementioned class within the gem5 standard
library, to let other ISAs and scripts make use of it.
Adding a cpu cluster class to the gem5 library will have the
benefit of standardizing the interface to cpus in the toplevel
configs
Most of the new class still resides in the python world: we want the
class to be as generic as possible and we want to make its use
optional
[1]: https://github.com/gem5/gem5/blob/v22.0.0.0/\
configs/example/arm/devices.py#L96
Change-Id: Idb05263a244e28bffa9eac811c6deb62ebb76a74
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/65891
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
When decode width is larger than fetch width, the skid buffer
overflow happens at decode stage. The decode stage assumes
that fetch stage sends instructions as many as the fetch width,
but it sends them at decode width rate.
This patch makes the decode stage set its skid buffer size
according to the decode width.
Change-Id: I90ee43d16c59a4c9305c77bbfad7e4cdb2b9cffa
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67231
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Hanhwi Jang <jang.hanhwi@gmail.com>
Reviewed-by: Tom Rollet <tom.rollet@huawei.com>
Tested-by: kokoro <noreply+kokoro@google.com>
An example case,
```python
mem_side_port = RequestPort(
"This port sends requests and " "receives responses"
)
```
This is the residue of running the python formatter.
This is done by finding all tokens matching the regex `"\s"(?![.;"])`
and manually replacing them by empty strings.
Change-Id: Icf223bbe889e5fa5749a81ef77aa6e721f38b549
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/66111
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Clang Version 14 throws a warning "use of bitwise '&/|' with boolean
operands" for cases where bitwise operations are used where boolean
operations are intended.
This occurred in "WriteMast.hh", "data.isa", and "decode.cc" where
boolean values were being compared using the bitwise operands. While
bitwise operations are equivalent, they have been changed to boolean
operations in this patch to avoid the clang-14 warning.
Change-Id: Ic7583e13a325661712c75c8e1b234c4878832352
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/64172
Reviewed-by: Tom Rollet <tom.rollet@huawei.com>
Reviewed-by: Kunal Pai <kunpai@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
The KVM_ISA setting was moved into a CONF dict, but the code which
ensured it had a default if there was no possible KVM hosting ISA was
still setting that variable in the base environment dict. This moves
the setting into the CONF dict instead.
Change-Id: I067c969dd761b2cdb098bcba6cd6a4b643d2d427
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/63752
Reviewed-by: Earl Ou <shunhsingou@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Add control/branch instructions committed stat to Minor CPU. The stats
can be found in board.processor.cores.core.committedControl_0 in
stats.txt. The stats counted are IsControl, IsDirectControl,
IsIndirectControl, IsCondControl, IsUncondControl, IsCall, and IsReturn.
IsControl tracks the total control/branch instructions committed.
Use inst->staticInst->isControl() flag to determine if an instruction is
a control or not, and then using other flags in the StaticInstFlags to
determine the type of control instruction and tracking the committed
ones.
Jira Issue: https://gem5.atlassian.net/browse/GEM5-1283
Change-Id: Iee1010fdf0fa4078ebe1c56b437295abdb5f4469
Co-authored-by: Kunal Pai <kunpai@ucdavis.edu>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/63358
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: ZHENGRONG WANG <seanyukigeek@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
The way these were set up, there would be a conflict between SimObject
files with the same name set up for different ISAs.
This change creates a single file which tries to determine how many ISAs
are enabled, and if there is exactly one, it creates a backwards
compatible alias for the ISA specific CPU types.
Change-Id: Iab358c2880d49222e814a98354c81d0f306fe1fc
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52493
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
The TARGET_ISA variable would let you select one ISA from a list of
possible ISAs. That has now been replaced with USE_ARM_ISA, USE_X86_ISA,
etc, variables which are boolean on or off. That will allow any number
of ISAs to be enabled or disabled individually. Enabling something other
than exactly one of these will probably prevent you from getting a
working gem5 binary, but those problems are being addressed in other,
parallel change series.
I decided to use the USE_ prefix since it was consistent with most other
on/off variables we have in gem5. One noteable exception is the
BUILD_GPU setting which, you could convincingly argue, is a better
prefix than USE_. Another option would be to use CONFIG_, in
anticipation of using a kconfig style config mechanism in gem5.
It seemed premature to start using a CONFIG_ prefix here, and if we
decide to switch to some other prefix like BUILD_, it should be a
purposeful choice and not something somebody just starts using.
Change-Id: I90fef2835aa4712782e6c1313fbf564d0ed45538
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52491
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
This makes RegIds and the RegClass-es associated with them responsible
for their own flattening. If they don't need to be flattened (a common
case) then they just mark themselves as already flat and that step can
be skipped.
This will also make it possible to get rid of the (get|set)RegFlat APIs,
since if you want to use flattened registers, you'll either have or
create a flattened RegId and pass it into the same (get|set)Reg method.
By making flattening work on RegIds instead of RegIndexes, this will
also make it possible for registers to start out in one RegClass and
move into another one. This would be useful if, for instance, there were
multiple groups of integer registers which had different indexing
semantics, but which should all end up in the same pool for renaming.
For instance, on x86, there are three distinct classes of FP registers.
They are the MMX registers, the pairs of registers which back the XMM
registers, and the X87 registers. Only the last of these needs
flattening. These could all be treated as different RegClass-es
pre-flattening, and could converge on the underlying floating point
register file post-flattening.
Another example in x86 is that some registers can encode that they
should refer to either the first byte of one register, or the second
byte of another register. This only applies to some registers though,
and so only those would need to go through the flattening step.
Another major advantage is that this removes the need for flattening
functions on the ISA object. Having those, and treating the ISA object
as a TheISA::ISA instead of the more generic BaseISA, was done to make
the flattening functions inline, and to make them fold away in cases
where flattening is not necessary. This new scheme isn't *quite* as
streamline as that, since you'll actually need to check if something is
already flattened. You won't, however, need to check what type the
register is and then look up the right flattening function, so that will
likely compensate.
Change-Id: I3c648cc8c0776b0e1020504113445b7d033e665f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/51227
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
