arm,sparc,x86,base,cpu,sim: Replace the Twin(32|64)_t types with.

Replace them with std::array<>s.

Change-Id: I76624c87a1cd9b21c386a96147a18de92b8a8a34
Reviewed-on: https://gem5-review.googlesource.com/6602
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

SPARC: Make PSTATE and HPSTATE a BitUnion.

This gets rid of cryptic bits of code with lots of bit manipulation, and makes
some comments redundant.

ISA parser: Define operand types with a ctype directly.

Style: Replace some tabs with spaces.

SPARC: Take advantage of new PCState syntax.

SPARC: Clean up some historical style issues.

ISA,CPU,etc: Create an ISA defined PC type that abstracts out ISA behaviors.



This change is a low level and pervasive reorganization of how PCs are managed
in M5. Back when Alpha was the only ISA, there were only 2 PCs to worry about,
the PC and the NPC, and the lsb of the PC signaled whether or not you were in
PAL mode. As other ISAs were added, we had to add an NNPC, micro PC and next
micropc, x86 and ARM introduced variable length instruction sets, and ARM
started to keep track of mode bits in the PC. Each CPU model handled PCs in
its own custom way that needed to be updated individually to handle the new
dimensions of variability, or, in the case of ARMs mode-bit-in-the-pc hack,
the complexity could be hidden in the ISA at the ISA implementation's expense.
Areas like the branch predictor hadn't been updated to handle branch delay
slots or micropcs, and it turns out that had introduced a significant (10s of
percent) performance bug in SPARC and to a lesser extend MIPS. Rather than
perpetuate the problem by reworking O3 again to handle the PC features needed
by x86, this change was introduced to rework PC handling in a more modular,
transparent, and hopefully efficient way.


PC type:

Rather than having the superset of all possible elements of PC state declared
in each of the CPU models, each ISA defines its own PCState type which has
exactly the elements it needs. A cross product of canned PCState classes are
defined in the new "generic" ISA directory for ISAs with/without delay slots
and microcode. These are either typedef-ed or subclassed by each ISA. To read
or write this structure through a *Context, you use the new pcState() accessor
which reads or writes depending on whether it has an argument. If you just
want the address of the current or next instruction or the current micro PC,
you can get those through read-only accessors on either the PCState type or
the *Contexts. These are instAddr(), nextInstAddr(), and microPC(). Note the
move away from readPC. That name is ambiguous since it's not clear whether or
not it should be the actual address to fetch from, or if it should have extra
bits in it like the PAL mode bit. Each class is free to define its own
functions to get at whatever values it needs however it needs to to be used in
ISA specific code. Eventually Alpha's PAL mode bit could be moved out of the
PC and into a separate field like ARM.

These types can be reset to a particular pc (where npc = pc +
sizeof(MachInst), nnpc = npc + sizeof(MachInst), upc = 0, nupc = 1 as
appropriate), printed, serialized, and compared. There is a branching()
function which encapsulates code in the CPU models that checked if an
instruction branched or not. Exactly what that means in the context of branch
delay slots which can skip an instruction when not taken is ambiguous, and
ideally this function and its uses can be eliminated. PCStates also generally
know how to advance themselves in various ways depending on if they point at
an instruction, a microop, or the last microop of a macroop. More on that
later.

Ideally, accessing all the PCs at once when setting them will improve
performance of M5 even though more data needs to be moved around. This is
because often all the PCs need to be manipulated together, and by getting them
all at once you avoid multiple function calls. Also, the PCs of a particular
thread will have spatial locality in the cache. Previously they were grouped
by element in arrays which spread out accesses.


Advancing the PC:

The PCs were previously managed entirely by the CPU which had to know about PC
semantics, try to figure out which dimension to increment the PC in, what to
set NPC/NNPC, etc. These decisions are best left to the ISA in conjunction
with the PC type itself. Because most of the information about how to
increment the PC (mainly what type of instruction it refers to) is contained
in the instruction object, a new advancePC virtual function was added to the
StaticInst class. Subclasses provide an implementation that moves around the
right element of the PC with a minimal amount of decision making. In ISAs like
Alpha, the instructions always simply assign NPC to PC without having to worry
about micropcs, nnpcs, etc. The added cost of a virtual function call should
be outweighed by not having to figure out as much about what to do with the
PCs and mucking around with the extra elements.

One drawback of making the StaticInsts advance the PC is that you have to
actually have one to advance the PC. This would, superficially, seem to
require decoding an instruction before fetch could advance. This is, as far as
I can tell, realistic. fetch would advance through memory addresses, not PCs,
perhaps predicting new memory addresses using existing ones. More
sophisticated decisions about control flow would be made later on, after the
instruction was decoded, and handed back to fetch. If branching needs to
happen, some amount of decoding needs to happen to see that it's a branch,
what the target is, etc. This could get a little more complicated if that gets
done by the predecoder, but I'm choosing to ignore that for now.


Variable length instructions:

To handle variable length instructions in x86 and ARM, the predecoder now
takes in the current PC by reference to the getExtMachInst function. It can
modify the PC however it needs to (by setting NPC to be the PC + instruction
length, for instance). This could be improved since the CPU doesn't know if
the PC was modified and always has to write it back.


ISA parser:

To support the new API, all PC related operand types were removed from the
parser and replaced with a PCState type. There are two warts on this
implementation. First, as with all the other operand types, the PCState still
has to have a valid operand type even though it doesn't use it. Second, using
syntax like PCS.npc(target) doesn't work for two reasons, this looks like the
syntax for operand type overriding, and the parser can't figure out if you're
reading or writing. Instructions that use the PCS operand (which I've
consistently called it) need to first read it into a local variable,
manipulate it, and then write it back out.


Return address stack:

The return address stack needed a little extra help because, in the presence
of branch delay slots, it has to merge together elements of the return PC and
the call PC. To handle that, a buildRetPC utility function was added. There
are basically only two versions in all the ISAs, but it didn't seem short
enough to put into the generic ISA directory. Also, the branch predictor code
in O3 and InOrder were adjusted so that they always store the PC of the actual
call instruction in the RAS, not the next PC. If the call instruction is a
microop, the next PC refers to the next microop in the same macroop which is
probably not desirable. The buildRetPC function advances the PC intelligently
to the next macroop (in an ISA specific way) so that that case works.


Change in stats:

There were no change in stats except in MIPS and SPARC in the O3 model. MIPS
runs in about 9% fewer ticks. SPARC runs with 30%-50% fewer ticks, which could
likely be improved further by setting call/return instruction flags and taking
advantage of the RAS.


TODO:

Add != operators to the PCState classes, defined trivially to be !(a==b).
Smooth out places where PCs are split apart, passed around, and put back
together later. I think this might happen in SPARC's fault code. Add ISA
specific constructors that allow setting PC elements without calling a bunch
of accessors. Try to eliminate the need for the branching() function. Factor
out Alpha's PAL mode pc bit into a separate flag field, and eliminate places
where it's blindly masked out or tested in the PC.

Make the GSR into a renamed control register. It should be split into a renamed part and a control part for the different bitfields, but the renamed part is all that's actually used.

Make the fsr a serializing register. Other control registers probably need this as well.

Create a filter and a union to translate the SPARC instruction implementations from using doubles to using concatenated singles.

make ldtw(a) -- Twin 32 bit load work correctly -- by doing it the same way as the twin 64 bit loads

src/arch/isa_parser.py:
src/arch/sparc/isa/decoder.isa:
src/arch/sparc/isa/operands.isa:
src/base/bigint.hh:
src/cpu/simple/atomic.cc:
src/cpu/simple/timing.cc:
src/mem/packet_access.hh:
make ldtw(a) Twin 32 bit load work correctly

make m5 readfile work on solaris... we can have a solaris regression soon!

src/arch/sparc/isa/decoder.isa:
add readfile and break to sparc decoder
src/arch/sparc/isa/operands.isa:
fix O0-O5 operands registers
util/m5/Makefile.sparc:
Make sparc makefile compile a 64bit binary
util/m5/m5.c:
readfile was in here twice, once will be sufficient I think
util/m5/m5op_sparc.S:
implement readfile and debugbreak

add pseduo instruction support for sparc

util/m5/Makefile.alpha:
Clean up to make it a bit easier to muck with
util/m5/Makefile.alpha:
Make the makefile more reasonable
util/m5/Makefile.alpha:
Remove authors from copyright.
util/m5/Makefile.alpha:
Updated Authors from bk prs info
util/m5/Makefile.alpha:
bk cp Makefile Makefile.alpha
src/arch/sparc/tlb.cc:
Clean up the cache code a little bit and make sure the uncacbale bit is set when appropriate
src/arch/alpha/isa/decoder.isa:
src/sim/pseudo_inst.cc:
src/sim/pseudo_inst.hh:
Rename AlphaPseudo -> PseudoInst since it's all generic
src/arch/sparc/isa/bitfields.isa:
src/arch/sparc/isa/decoder.isa:
src/arch/sparc/isa/includes.isa:
src/arch/sparc/isa/operands.isa:
Add support for pseudo instructions in sparc
util/m5/Makefile.alpha:
util/m5/Makefile.sparc:
split off alpha make file and sparc make file for m5 app
util/m5/m5.c:
ivle and ivlb aren't used anymore
util/m5/m5op.h:
stdint seems like a more generic better fit here
util/m5/m5op_alpha.S:
move the op ids into their own header file since we can share them between sparc and alpha

rename store conditional stuff as extra data so it can be used for conditional swaps as well
Add support for a twin 64 bit int load
Add Memory barrier and write barrier flags as appropriate
Make atomic memory ops atomic

src/arch/alpha/isa/mem.isa:
src/arch/alpha/locked_mem.hh:
src/cpu/base_dyn_inst.hh:
src/mem/cache/cache_blk.hh:
src/mem/cache/cache_impl.hh:
rename store conditional stuff as extra data so it can be used for conditional swaps as well
src/arch/alpha/types.hh:
src/arch/mips/types.hh:
src/arch/sparc/types.hh:
add a largest read data type for statically allocating read buffers in atomic simple cpu
src/arch/isa_parser.py:
Add support for a twin 64 bit int load
src/arch/sparc/isa/decoder.isa:
Make atomic memory ops atomic
Add Memory barrier and write barrier flags as appropriate
src/arch/sparc/isa/formats/mem/basicmem.isa:
add post access code block and define a twinload format for twin loads
src/arch/sparc/isa/formats/mem/blockmem.isa:
remove old microcoded twin load coad
src/arch/sparc/isa/formats/mem/mem.isa:
swap.isa replaces the code in loadstore.isa
src/arch/sparc/isa/formats/mem/util.isa:
add a post access code block
src/arch/sparc/isa/includes.isa:
need bigint.hh for Twin64_t
src/arch/sparc/isa/operands.isa:
add a twin 64 int type
src/cpu/simple/atomic.cc:
src/cpu/simple/atomic.hh:
src/cpu/simple/base.hh:
src/cpu/simple/timing.cc:
add support for twinloads
add support for swap and conditional swap instructions
rename store conditional stuff as extra data so it can be used for conditional swaps as well
src/mem/packet.cc:
src/mem/packet.hh:
Add support for atomic swap memory commands
src/mem/packet_access.hh:
Add endian conversion function for Twin64_t type
src/mem/physical.cc:
src/mem/physical.hh:
src/mem/request.hh:
Add support for atomic swap memory commands
Rename sc code to extradata

Fix the Frs?s operands to use single width by default, rather than double width.

Merge zizzer:/bk/newmem
into zower.eecs.umich.edu:/eecshome/m5/newmem

src/arch/sparc/isa/formats/mem/blockmem.isa:
src/arch/sparc/isa/operands.isa:
Hand Merge

Support for twin loads.

src/arch/sparc/isa/decoder.isa:
Changed the names of the twin loads to match the 2005 spec. They still use the old format though.
src/arch/sparc/isa/formats/mem/blockmem.isa:
Added code to generate twin loads
src/arch/sparc/isa/formats/mem/util.isa:
Added an alignment check for twin loads
src/arch/sparc/isa/operands.isa:
Comment explaining twin load operands.

Made changes to CWP be non speculative.

Move the SyscallReturn class into sim/syscallreturn.hh. Also move some miscregs into the integer register file so they get renamed.

src/arch/alpha/syscallreturn.hh:
src/arch/mips/syscallreturn.hh:
src/sim/syscallreturn.hh:
Move the SyscallReturn class into sim/syscallreturn.hh
src/arch/sparc/faults.cc:
src/arch/sparc/isa/operands.isa:
src/arch/sparc/isa_traits.hh:
src/arch/sparc/miscregfile.cc:
src/arch/sparc/miscregfile.hh:
src/arch/sparc/process.cc:
src/arch/sparc/sparc_traits.hh:
Move some miscregs into the integer register file so they get renamed.

Fixes to the isa description.

src/arch/sparc/isa/base.isa:
Fix a constant.
src/arch/sparc/isa/decoder.isa:
Made carry calculation more consistent.
src/arch/sparc/isa/operands.isa:
Use the right constant.

Added StrandStsReg operand.

Fix up instructions to read and write control registers, and got rid of the control register fields which won't work on a big endian host.

Add an integer microcode register.

Fixed the priv instruction format.

src/arch/sparc/isa/formats/priv.isa:
Fix the priv format so that it uses isa_parser operands rather than accessing the registers directly in checkCode. Also, the expressions needed to be negated.
src/arch/sparc/isa/operands.isa:
Added an Hpstate operand, and adjusted the numbering.

Broke Load/Store instructions into microcode, and partially refactored memory operations in the SPARC ISA description.

Zeroed out the actual LSB in addition to moving it's original value the MSB.

Changed how floating point register numbers are decoded to fit with the spec.

Some support for handling block loads and stores and ASIs properly.

src/arch/sparc/isa/bitfields.isa:
Added a field to retrieve the asi from the ExtMachInst
src/arch/sparc/isa/decoder.isa:
Fixed up how the size of memory operations where handled, and use the new EXT_ASI bit field.
src/arch/sparc/isa/formats.isa:
add includes for the new formats.
src/arch/sparc/isa/formats/basic.isa:
Add a template for BasicDecodeWithMnemonic which is needed by the unimp format.
src/arch/sparc/isa/formats/mem.isa:
Change around the memory format to figure out the memory access width on its own.
src/arch/sparc/isa/operands.isa:
Added support for the operands of block loads/stores which are offset from Frd.
src/arch/sparc/utility.hh:
Encoded the ASI into the ExtMachInst

Now ignore sigaction

src/arch/sparc/isa/operands.isa:
Added the GSR register as a control register

Fixed subtract with carry, and started some work with floating point.

src/arch/sparc/isa/decoder.isa:
fixed subc, subccc, added decoding for impdep1 to fit with ua2005, and started work on floating point.
src/arch/sparc/isa/operands.isa:
Added in floating point operands, and changed the numbering of operands.
src/arch/sparc/regfile.hh:
Fixed some memory errors related to floating point.

Implement PR/HPR/ASR for full system
Rip out storage in miscreg file that will never store anything
Add storage and defines for Priv and Hyperpriv registers
Change defines to match the spec register numbers
Change the way misc registers are named to match the spec with offsets to deal with ASR/PR/HPR/FSR.
Change contextval to an int since both global registers and windowed registers are indexed by int in UA2005.
Use bitfields for things that are rarely used in decoder
Instead of decoding ASR/PR/HPR and having a specfic instruction, use a generic instruction instead

Still todo:
Protect rdpr, rdhpr, wrpr, wrhpr with checks that fault in insufficient privs
Deal with signaling interrupts on timer expiration
Deal with writes to softint/PIL generating interrupts how those are vectored to the CPU

Other misc:
Instruction decoding needs major help!

src/arch/sparc/isa/decoder.isa:
Remove tons of MISCREG_XXXX defines that weren't used and ControlRegs in that were never used. Ones that were used rarely
changed to bitfields.
src/arch/sparc/isa/formats/integerop.isa:
These seems like a whole lot of overkill in printing, but i'll leave it the way it is for now. Allow Ccr to be set
at once
src/arch/sparc/isa/formats/priv.isa:
PrivTick is handled by miscreg now, don't need a seperate class for it
src/arch/sparc/isa/operands.isa:
prune the number of control regs down to a reasonable amount
src/arch/sparc/isa_traits.hh:
Replace 8 defines with 1 and flick some bits
src/arch/sparc/process.cc:
Better to clean the entire registers that specific bits which leads to indetermanistic behavior.
src/arch/sparc/regfile.hh:
Rip out storage that will never be backed by anything
Add storage for Priv and Hyperpriv registers
change defines to match the spec
change the way misc registers are named to match the spec with offsets to deal with ASR/PR/HPR/FSR.
change contextval to an int since both global registers and windowed registers are indexed by int in UA2005.

New directory structure:
- simulator source now in 'src' subdirectory
- imported files from 'ext' repository
- support building in arbitrary places, including
outside of the source tree. See comment at top
of SConstruct file for more details.
Regression tests are temporarily disabled; that
syetem needs more extensive revisions.

SConstruct:
Update for new directory structure.
Modify to support build trees that are not subdirectories
of the source tree. See comment at top of file for
more details.
Regression tests are temporarily disabled.
src/arch/SConscript:
src/arch/isa_parser.py:
src/python/SConscript:
Update for new directory structure.