While I was working on the disassembler styling for ARM I noticed that
the whitespace in the cpsie instruction was inconsistent with most of
the other ARM disassembly output, the disassembly for cpsie looks like
this:
cpsie if,#10
notice there's no space before the '#10' immediate, most other ARM
instructions have a space before each operand.
This commit updates the disassembler to add the missing space, and
updates the tests I found that tested this instruction.
This commit intends to move operands that require very special handling or
operand types that are so minor (e.g. only useful on a few instructions)
under "W". I also intend this "W" to be "temporary" operand storage until
we can find good two character (or less) operand type.
In this commit, prefetch offset operand "f" for 'Zicbop' extension is moved
to "Wif" because of its special handling (and allocating single character
"f" for this operand type seemed too much).
Current expected allocation guideline is as follows:
1. 'W'
2. The most closely related single-letter extension in lowercase
(strongly recommended but not mandatory)
3. Identify operand type
The author currently plans to allocate following three-character operand
types (for operands including instructions from unratified extensions).
1. "Wif" ('Zicbop': fetch offset)
2. "Wfv" (unratified 'Zfa': value operand from FLI.[HSDQ] instructions)
3. "Wfm" / "WfM"
'Zfh', 'F', 'D', 'Q': rounding modes "m" with special handling
solely for widening conversion instructions.
gas/ChangeLog:
* config/tc-riscv.c (validate_riscv_insn, riscv_ip): Move from
"f" to "Wif".
opcodes/ChangeLog:
* riscv-dis.c (print_insn_args): Move from "f" to "Wif".
* riscv-opc.c (riscv_opcodes): Reflect new operand type.
All encoding spaces can be used this way; there's a certain risk that
the bits presently reserved could be used for other purposes down the
road, but people using .insn are expected to know what they're doing
anyway. Plus this way there's at least _some_ way to have those bits
set.
For now this will only allow operand-less insns to be encoded this way.
This patch adds the RPRFM (range prefetch) instruction.
It was introduced as part of SME2, but it belongs to the
prefetch hint space and so doesn't require any specific
ISA flags.
The aarch64_rprfmop_array initialiser (deliberately) only
fills in the leading non-null elements.
This patch adds the SVE FDOT, SDOT and UDOT instructions,
which are available when FEAT_SME2 is implemented. The patch
also reorders the existing SVE_Zm3_22_INDEX to keep the
operands numerically sorted.
This patch adds SUNPK and UUNPK, which unpack one register's
worth of elements to two registers' worth, or two registers'
worth to four registers' worth.
There are two instruction formats here:
- SQRSHR, SQRSHRU and UQRSHR, which operate on lists of two
or four registers.
- SQRSHRN, SQRSHRUN and UQRSHRN, which operate on lists of
four registers.
These are the first SME2 instructions to have immediate operands.
The patch makes sure that, when parsing SME2 instructions with
immediate operands, the new predicate-as-counter registers are
parsed as registers rather than as #-less immediates.
There are two instruction formats here:
- SQCVT, SQCVTU and UQCVT, which operate on lists of two or
four registers.
- SQCVTN, SQCVTUN and UQCVTN, which operate on lists of
four registers.
This patch adds the SME2 versions of the FP<->integer conversion
instructions FCVT* and *CVTF. It also adds FP rounding instructions
FRINT*, which share the same format.
BFDOT, FDOT and USDOT share the same instruction format.
SDOT and UDOT share a different format. SUDOT does not
have the multi vector x multi vector forms, since they
would be redundant with USDOT.
SMLALL, SMLSLL, UMLALL and UMLSLL have the same format.
USMLALL and SUMLALL allow the same operand types as those
instructions, except that SUMLALL does not have the multi-vector
x multi-vector forms (which would be redundant with USMLALL).
The {BF,F,S,U}MLAL and {BF,F,S,U}MLSL instructions share the same
encoding. They are the first instance of a ZA (as opposed to ZA tile)
operand having a range of offsets. As with ZA tiles, the expected
range size is encoded in the operand-specific data field.
This patch adds the SME2 multi-register forms of F{MAX,MIN}{,NM}
and {S,U}{MAX,MIN}. SQDMULH, SRSHL and URSHL have the same form
as SMAX etc., so the patch adds them too.
Add support for the SME2 ADD. SUB, FADD and FSUB instructions.
SUB and FSUB have the same form as ADD and FADD, except that
ADD also has a 2-operand accumulating form.
The 64-bit ADD/SUB instructions require FEAT_SME_I16I64 and the
64-bit FADD/FSUB instructions require FEAT_SME_F64F64.
These are the first instructions to have tied register list
operands, as opposed to tied single registers.
The parse_operands change prevents unsuffixed Z registers (width==-1)
from being treated as though they had an Advanced SIMD-style suffix
(.4s etc.). It means that:
Error: expected element type rather than vector type at operand 2 -- `add za\.s\[w8,0\],{z0-z1}'
becomes:
Error: missing type suffix at operand 2 -- `add za\.s\[w8,0\],{z0-z1}'
SME2 adds lookup table instructions for quantisation. They use
a new lookup table register called ZT0.
LUTI2 takes an unsuffixed SVE vector index of the form Zn[<imm>],
which is the first time that this syntax has been used.
Implementation-wise, the main things to note here are:
- the WHILE* instructions have forms that return a pair of predicate
registers. This is the first time that we've had lists of predicate
registers, and they wrap around after register 15 rather than after
register 31.
- the predicate-as-counter WHILE* instructions have a fourth operand
that specifies the vector length. We can treat this as an enumeration,
except that immediate values aren't allowed.
- PEXT takes an unsuffixed predicate index of the form PN<n>[<imm>].
This is the first instance of a vector/predicate index having
no suffix.
SME2 adds LD1 and ST1 variants for lists of 2 and 4 registers.
The registers can be consecutive or strided. In the strided case,
2-register lists have a stride of 8, starting at register x0xxx.
4-register lists have a stride of 4, starting at register x00xx.
The instructions are predicated on a predicate-as-counter register in
the range pn8-pn15. Although we already had register fields with upper
bounds of 7 and 15, this is the first plain register operand to have a
nonzero lower bound. The patch uses the operand-specific data field
to record the minimum value, rather than having separate inserters
and extractors for each lower bound. This in turn required adding
an extra bit to the field.
SME2 defines new MOVA instructions for moving multiple registers
to and from ZA. As with SME, the instructions are also available
through MOV aliases.
One notable feature of these instructions (and many other SME2
instructions) is that some register lists must start at a multiple
of the list's size. The patch uses the general error "start register
out of range" when this constraint isn't met, rather than an error
specifically about multiples. This ensures that the error is
consistent between these simple consecutive lists and later
strided lists, for which the requirements aren't a simple multiple.
SME2 adds a new format for the existing SVE predicate registers:
predicates as counters rather than predicates as masks. In assembly
code, operands that interpret predicates as counters are written
pn<N> rather than p<N>.
This patch adds support for these registers and extends some
existing instructions to support them. Since the new forms
are just a programmer convenience, there's no need to make them
more restrictive than the earlier predicate-as-mask forms.
Some SME2 instructions operate on a range of consecutive ZA vectors.
This is indicated by syntax such as:
za[<Wv>, <imml>:<immh>]
Like with the earlier vgx2 and vgx4 support, we get better error
messages if the parser allows all ZA indices to have a range.
We can then reject invalid cases during constraint checking.
Many SME2 instructions operate on groups of 2 or 4 ZA vectors.
This is indicated by adding a "vgx2" or "vgx4" group size to the
ZA index. The group size is optional in assembly but preferred
for disassembly.
There is not a binary distinction between mnemonics that have
group sizes and mnemonics that don't, nor between mnemonics that
take vgx2 and mnemonics that take vgx4. We therefore get better
error messages if we allow any ZA index to have a group size
during parsing, and wait until constraint checking to reject
invalid sizes.
A quirk of the way errors are reported means that if an instruction
is wrong both in its qualifiers and its use of a group size, we'll
print suggested alternative instructions that also have an incorrect
group size. But that's a general property that also applies to
things like out-of-range immediates. It's also not obviously the
wrong thing to do. We need to be relatively confident that we're
looking at the right opcode before reporting detailed operand-specific
errors, so doing qualifier checking first seems resonable.
SME2 adds various new fields that are similar to
AARCH64_OPND_SME_ZA_array, but are distinguished by the size of
their offset fields. This patch adds _off4 to the name of the
field that we already have.
Until now, binutils has supported register ranges such
as { v0.4s - v3.4s } as an unofficial shorthand for
{ v0.4s, v1.4s, v2.4s, v3.4s }. The SME2 ISA embraces this form
and makes it the preferred disassembly. It also embraces wrapped
lists such as { z31.s - z2.s }, which is something that binutils
didn't previously allow.
The range form was already binutils's preferred disassembly for 3- and
4-register lists. This patch prefers it for 2-register lists too.
The patch also adds support for wrap-around.
SME2 has instructions that accept strided register lists,
such as { z0.s, z4.s, z8.s, z12.s }. The purpose of this
patch is to extend binutils to support such lists.
The parsing code already had (unused) support for strides of 2.
The idea here is instead to accept all strides during parsing
and reject invalid strides during constraint checking.
The SME2 instructions that accept strided operands also have
non-strided forms. The errors about invalid strides therefore
take a bitmask of acceptable strides, which allows multiple
possibilities to be summed up in a single message.
I've tried to update all code that handles register lists.
Some FLD_imm* suffixes used a counting scheme such as FLD_immN,
FLD_immN_2, FLD_immN_3, etc., while others used the lsb as the
suffix. The latter seems more mnemonic, and was a big help
in doing the SME2 work.
Similarly, the _10 suffix on FLD_SME_size_10 was nonobvious.
Presumably it indicated a 2-bit field, but it actually starts
in bit 22.
Quite a lot of SME2 instructions have an opcode bit that selects
between 32-bit and 64-bit forms of an instruction, with the 32-bit
forms being part of base SME2 and with the 64-bit forms being part
of an optional extension. It's nevertheless useful to have a single
opcode entry for both forms since (a) that matches the ISA definition
and (b) it tends to improve error reporting.
This patch therefore adds a libopcodes function called
aarch64_cpu_supports_inst_p that tests whether the target
supports a particular instruction. In future it will depend
on internal libopcodes routines.
This patch renames the OP_SME_* macros in aarch64-tbl.h so that
they follow the same scheme as the OP_SVE_* ones. It also uses
OP_SVE_ as the prefix, since there is no real distinction between
the SVE and SME uses of qualifiers: a macro defined for one can
be useful for the other too.
If an instruction has invalid qualifiers, GAS would report the
error against the final opcode entry that got to the qualifier-
checking stage. It seems better to report the error against
the opcode entry that had the closest match, just like we
pick the closest match within an opcode entry for the
"did you mean this?" message.
This patch adds the number of invalid operands as an
argument to AARCH64_OPDE_INVALID_VARIANT and then picks the
AARCH64_OPDE_INVALID_VARIANT with the lowest argument.
AARCH64_OPDE_REG_LIST took a single operand that specified the
expected number of registers. However, there are quite a few
SME2 instructions that have both 2-register forms and (separate)
4-register forms. If the user tries to use a 3-register list,
it isn't obvious which opcode entry they meant. Saying that we
expect 2 registers and saying that we expect 4 registers would
both be wrong.
This patch therefore switches the operand to a bitfield. If a
AARCH64_OPDE_REG_LIST is reported against multiple opcode entries,
the patch ORs up the expected lengths.
This has no user-visible effect yet. A later patch adds more error
strings, alongside tests that use them.
SVE register lists were classified as SVE_REG, since there had been
no particular reason to separate them out. However, some SME2
instructions have tied register list operands, and so we need to
distinguish registers and register lists when checking whether two
operands match.
Also, the register list operands used a general error message,
even though we already have a dedicated error code for register
lists that are the wrong length.
