The latest Power ISA introduces two new bits that record
carry and overflow out of bit 31 of the result, namely
CA32 and OV32 respectively, thereby changing the behaviour
of the add and subtract instructions that set them. Also,
now that 64-bit registers are being used, the nature of
the result, i.e. less than, greater than or equal to zero,
must be set by a 64-bit signed comparison of the result
to zero. This fixes the following instructions.
* Add Immediate (addi)
* Add Immediate Shifted (addis)
* Add (add[o][.])
* Subtract From (subf[o][.])
* Add Immediate Carrying (addic)
* Add Immediate Carrying and Record (addic.)
* Subtract From Immediate Carrying (subfic)
* Add Carrying (addc[o][.])
* Subtract From Carrying (subfc[o][.])
* Add Extended (adde[o][.])
* Subtract From Extended (subfe[o][.])
* Add to Zero Extended (addze[o][.])
* Subtract From Zero Extended (subfze[o][.])
* Negate (neg[o][.])
* Multiply Low Immediate (mulli)
* Multiply Low Word (mullw[o][.])
* Multiply High Word (mulhw[.])
* Multiply High Word Unsigned (mulhwu[.])
* Divide Word (divw[o][.])
* Divide Word Unsigned (divwu[o][.])
Change-Id: I8c79f1dca8b19010ed7b734d7ec9bb598df428c3
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40899
Reviewed-by: Boris Shingarov <shingarov@labware.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This changes the base classes for integer arithmetic
instructions and introduces two new classes that are used
to distinguish between instructions using register and
immediate operands.
Decoding has also been consolidated using formats that can
generate code after determining if an instruction records
carry and overflow and also if it records the nature of the
result, i.e. lesser than, greater than or equal to zero.
However, for multiply and divide instructions, the code to
determine if an overflow has occurred has been moved to the
instruction definition itself. The formats have also been
updated to make use of the new base classes.
Change-Id: I23d70ac4bad4d25d876308db0b3564c092bf574c
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40898
Reviewed-by: Boris Shingarov <shingarov@labware.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This introduces new formats for DS form instructions and
adds the following instructions.
* Load Doubleword (ld)
* Load Doubleword Indexed (ldx)
* Load Doubleword with Update (ldu)
* Load Doubleword with Update Indexed (ldux)
* Store Doubleword (std)
* Store Doubleword Indexed (stdx)
* Store Doubleword with Update (stdu)
* Store Doubleword with Update Indexed (stdux)
Change-Id: I2a88364e82a11685e081f57be5fd5afd44335668
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40895
Reviewed-by: Boris Shingarov <shingarov@labware.com>
Reviewed-by: lkcl <luke.leighton@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Now that 64-bit registers and operands are being used, the
instructions for words must read or write just one word at
a time. This fixes the following instructions.
* Load Word and Zero (lwz)
* Load Word and Zero Indexed (lwzx)
* Load Word and Zero with Update (lwzu)
* Load Word and Zero with Update Indexed (lwzux)
* Load Word And Reserve Indexed (lwarx)
* Store Word (stw)
* Store Word Indexed (stwx)
* Store Word with Update (stwu)
* Store Word with Update Indexed (stwux)
* Store Word Conditional Indexed (stwcx.)
This also fixes decoding of load-store update instructions
for some special scenarios when RA is zero or RA and RT
are the same. In such cases, the instruction is considered
invalid.
Change-Id: I6787d3614ba8f1b1cbf30a49f85ef422324d7c21
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40893
Reviewed-by: Boris Shingarov <shingarov@labware.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The only thing brought in by arch/types.hh is TheISA::PCState. Instead
of having the other types around where they could be used accidentally,
and to make it more obvious what's being exported, this change splits
PCState out into a new switching header called arch/pcstate.hh. The
original arch/types.hh is no longer a switching header, and includes
pcstate.hh.
Change-Id: I8dfd298349e4565f316f7b9a028703289ada6010
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40177
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
These had been templated on a type, and then the width of that type was
considered the amount the PC should advance when executing straight line
code. That type was MachInst, which was loosely the size of an
instruction, but was practically whatever sized data type was fed into
the decoder at a time.
Instead of tying this to a type, this change moves it over to be a
simple number. This avoids a level of indirection, and also further
decouples the type the decoder might use as input from the instruction
size.
Change-Id: I797876a33d27e759c7a6e23a658179201fabfa47
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40176
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
By moving the installation of even the first ThreadContext out of the
constructor, it's possible to construct the stub separately. We can then
move the code that creates the stub out of the base class and into
architecture specific sub-classes.
Change-Id: I0dfd53a3135ebc98ec49acf81d83e58830bc365c
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/44618
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
In this context, the decoder width is the number of bytes that are fed
into the decoder at once. This is frequently the same as the size of an
instruction, but in instructions with occasionally variable instruction
sizes (ARM, RISCV), or extremely variable instruction sizes (x86) there
may be no relation.
Rather than determining the amount of data to feed to the decoder based
on a MachInst type defined by each ISA, this new interface adds some new
properties to the base InstDecoder class each arch specific decoder
inherits from. These are the size of the incoming buffer, a pointer to
wherever that data should end up, and a mask for masking a PC value so
it aligns with the instruction size.
These values are filled in by a templated InstDecoder constructor which
is templated based on what would have historically been the MachInst
type.
Because the "moreBytes" method would historically accept a parameter of
type MachInst, this parameter has also been eliminated. Now, the
decoder's parent object should use the pointer and size values to fill
in the buffer moreBytes reads. Then when moreBytes is called, it just
uses the buffer without having to show what its type is externally.
Change-Id: I0642cdb6a61e152441ca4ce47d748639175cda90
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40175
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This changes the base classes for load-store instructions
and introduces two new classes for DS form instructions
which use a shifted signed immediate field as the offset
from the base address and for X form instructions which
use registers for both the offset and the base address.
The formats have also been updated to make use of the new
base classes.
Change-Id: Ib5d1bb5d7747813e0e5b1e3075489f1a3aa72660
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40892
Reviewed-by: Boris Shingarov <shingarov@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
When RS and RA are both used as operands by an instruction,
RS takes precedence over RA. In such cases, either both the
register operands are used as sources or RS is a source and
RA is a destination.
This changes the order by giving RS the highest precedence
and will be useful for proper disassembly generation.
Change-Id: If351a03a814653f2f371afa936ec7a5cd4377b3a
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40890
Reviewed-by: Boris Shingarov <shingarov@gmail.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This adds the definition of the Target Address Register (TAR)
and the following instructions that are associated with it.
* Move To Target Address Register (mttar)
* Move From Target Address Register (mftar)
* Branch Conditional to Branch Target Address Register (bctar[l])
Change-Id: I30f54ebd38b503fb6c9ba9dd74d00ccbbc0f8318
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40889
Reviewed-by: Boris Shingarov <shingarov@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Among the register-based conditional branch instructions,
the ones using CTR should not decrement CTR when the bit
corresponding to this action is set in the BO field of
the instruction. In this case, the instruction should be
considered invalid. This fixes the following instructions.
* Branch Conditional to Count Register (bcctr[l])
Change-Id: Ib2dbf2bc36fced580b4b7f7b76783f68361f6bbf
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40887
Reviewed-by: Boris Shingarov <shingarov@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This changes the base classes for branch instructions and
switches to two high-level classes for unconditional and
conditional branches. The conditional branches are further
classified based on whether they use an immediate field or
a register for determining the target address.
Decoding has also been consolidated using formats that can
generate code after determining if an instruction branches
to an absolute address or a PC-relative address, or if it
implicitly sets the return address by looking at the AA and
LK bits.
Change-Id: I5fa7db7b6693586b4ea3c71e5cad8a60753de29c
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40886
Reviewed-by: Boris Shingarov <shingarov@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
When multiple instructions share the same primary opcode,
the decoder can distinguish between them by looking at the
extended opcode field. However, the length and position of
the extended opcode field can slightly vary depending on
the instruction form.
This ensures that the correct extended opcode fields are
used for decoding such instructions.
Change-Id: I8207568ac975587377abba8a9b221ca3097b8488
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40885
Reviewed-by: Boris Shingarov <shingarov@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
There is a design which has been put forward which eliminates the idea
of a zero register entirely, but in the mean time, to get rid of one
more ISA specific constant, this change moves the ZeroReg constant into
the RegClassInfo class, specifically the IntRegClass instance which is
published by each ISA.
When the idea of zero registers has been eliminated entirely from
non ISA specific code, this and the existing machinery can be
eliminated.
Change-Id: I4302a53220dd5ff6b9b47ecc765bddc6698310ca
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/42685
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This increases the width of the general-purpose registers
and some of the special purpose registers to 64 bits in
accordance with recent versions of the Power ISA. This
allows the registers to be used for both 32-bit and 64-bit
execution modes.
It should be noted that in 32-bit mode, the use of upper
word is dependent on the instruction being executed and in
some cases, this may be undefined.
Change-Id: I2a5865a66e4ceab45e42a833d425abdd6bd6bf55
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40881
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Boris Shingarov <shingarov@gmail.com>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
These were not caught by the previous patches because
the grep used ignored:
- anonymous structures
(e.g., "struct {")
- opening braces without leading spaces
(e.g., "struct Name{"),
- weird chars in auto-generation files
(e.g., "struct $name {").
- extra characters after the opening brace.
(e.g., "struct Name { // Comment")
- typedefs (note that this is not caught by the verifier)
(e.g., "typedef struct Name {")
Most of this has been fixed be grepping structures
with the following regex:
grep -nrE --exclude-dir=systemc \
"^ *(typedef)* *(struct|class|enum|union) [^{]*{$" src/
The following makes sure that "struct{" is captured:
grep -nrE --exclude-dir=systemc \
"^ *(struct|class|enum|union){" src/
To find cases that contain a comment after the
opening brace:
grep -nrE --exclude-dir=systemc \
"^ *(struct|class|enum|union)[^{]*{\s*//" src/
Change-Id: I9f822bed628d13b1a09ccd6059373aff63a8d7bd
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/43505
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
The only thing left in isa_traits.hh are two constants, one for the
number of bytes in a page, and one for how far to shift an address to
get the page number. To make it clear that this is the only thing
isa_traits.hh should be used for from this point forward (until it is
entirely eliminated), this change renames it to the much less generic
page_size.hh.
Also, because isa_traits.hh used to have *much* more stuff in it, it was
included in a lot of places it didn't need to be. This change also
clears out all these legacy includes while updating the actually needed
ones to the new name.
Change-Id: I939b01b117c53d620b6b0a98982f6f21dc2ada72
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/40179
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
