Commit Graph

55 Commits

Author SHA1 Message Date
Peter Maydell
d9c7adb601 target/arm: Store FPSR cumulative exception bits in env->vfp.fpsr
Currently we store the FPSR cumulative exception bits in the
float_status fields, and use env->vfp.fpsr only for the NZCV bits.
(The QC bit is stored in env->vfp.qc[].)

This works for TCG, but if QEMU was built without CONFIG_TCG (i.e.
with KVM support only) then we use the stub versions of
vfp_get_fpsr_from_host() and vfp_set_fpsr_to_host() which do nothing,
throwing away the cumulative exception bit state.  The effect is that
if the FPSR state is round-tripped from KVM to QEMU then we lose the
cumulative exception bits.  In particular, this will happen if the VM
is migrated.  There is no user-visible bug when using KVM with a QEMU
binary that was built with CONFIG_TCG.

Fix this by always storing the cumulative exception bits in
env->vfp.fpsr.  If we are using TCG then we may also keep pending
cumulative exception information in the float_status fields, so we
continue to fold that in on reads.

This change will also be helpful for implementing FEAT_AFP later,
because that includes a feature where in some situations we want to
cause input denormals to be flushed to zero without affecting the
existing state of the FPSR.IDC bit, so we need a place to store IDC
which is distinct from the various float_status fields.

(Note for stable backports: the bug goes back to 4a15527c9f but
this code was refactored in commits ea8618382aba..a8ab8706d4cc461, so
fixing it in branches without those refactorings will mean either
backporting the refactor or else implementing a conceptually similar
fix for the old code.)

Cc: qemu-stable@nongnu.org
Fixes: 4a15527c9f ("target/arm/vfp_helper: Restrict the SoftFloat use to TCG")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241011162401.3672735-1-peter.maydell@linaro.org
2024-10-29 15:04:46 +00:00
Peter Maydell
8b0898f8dd target/arm: Allow setting the FPCR.EBF bit for FEAT_EBF16
FEAT_EBF16 adds one new bit to the FPCR floating point control
register.  Allow this bit to be read and written when the ID
registers indicate the presence of the feature.

Note that because this new bit is not in FPSCR_FPCR_MASK the bit is
not visible in the AArch32 FPSCR, and FPSCR writes do not affect it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2024-09-05 13:12:35 +01:00
Peter Maydell
a8ab8706d4 target/arm: Allow FPCR bits that aren't in FPSCR
In order to allow FPCR bits that aren't in the FPSCR (like the new
bits that are defined for FEAT_AFP), we need to make sure that writes
to the FPSCR only write to the bits of FPCR that are architecturally
mapped, and not the others.

Implement this with a new function vfp_set_fpcr_masked() which
takes a mask of which bits to update.

(We could do the same for FPSR, but we leave that until we actually
are likely to need it.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240628142347.1283015-10-peter.maydell@linaro.org
2024-07-11 11:41:33 +01:00
Peter Maydell
db397a81ee target/arm: Rename FPSR_MASK and FPCR_MASK and define them symbolically
Now that we store FPSR and FPCR separately, the FPSR_MASK and
FPCR_MASK macros are slightly confusingly named and the comment
describing them is out of date.  Rename them to FPSCR_FPSR_MASK and
FPSCR_FPCR_MASK, document that they are the mask of which FPSCR bits
are architecturally mapped to which AArch64 register, and define them
symbolically rather than as hex values.  (This latter requires
defining some extra macros for bits which we haven't previously
defined.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240628142347.1283015-9-peter.maydell@linaro.org
2024-07-11 11:41:33 +01:00
Peter Maydell
a26db547b7 target/arm: Rename FPCR_ QC, NZCV macros to FPSR_
The QC, N, Z, C, V bits live in the FPSR, not the FPCR. Rename the
macros that define these bits accordingly.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240628142347.1283015-8-peter.maydell@linaro.org
2024-07-11 11:41:33 +01:00
Peter Maydell
ce07ea61ed target/arm: Store FPSR and FPCR in separate CPU state fields
Now that we have refactored the set/get functions so that the FPSCR
format is no longer the authoritative one, we can keep FPSR and FPCR
in separate CPU state fields.

As well as the get and set functions, we also have a scattering of
places in the code which directly access vfp.xregs[ARM_VFP_FPSCR] to
extract single fields which are stored there.  These all change to
directly access either vfp.fpsr or vfp.fpcr, depending on the
location of the field.  (Most commonly, this is the NZCV flags.)

We make the field in the CPU state struct 64 bits, because
architecturally FPSR and FPCR are 64 bits.  However we leave the
types of the arguments and return values of the get/set functions as
32 bits, since we don't need to make that change with the current
architecture and various callsites would be unable to handle
set bits in the high half (for instance the gdbstub protocol
assumes they're only 32 bit registers).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240628142347.1283015-7-peter.maydell@linaro.org
2024-07-11 11:41:33 +01:00
Peter Maydell
b167325e93 target/arm: Make vfp_set_fpscr() call vfp_set_{fpcr, fpsr}
Make vfp_set_fpscr() call vfp_set_fpsr() and vfp_set_fpcr()
instead of the other way around.

The masking we do when getting and setting vfp.xregs[ARM_VFP_FPSCR]
is a little awkward, but we are going to change where we store the
underlying FPSR and FPCR information in a later commit, so it will
go away then.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240628142347.1283015-4-peter.maydell@linaro.org
2024-07-11 11:41:33 +01:00
Peter Maydell
2de7cf9e05 target/arm: Make vfp_get_fpscr() call vfp_get_{fpcr, fpsr}
In AArch32, the floating point control and status bits are all in a
single register, FPSCR.  In AArch64, these were split into separate
FPCR and FPSR registers, but the bit layouts remained the same, with
no overlaps, so that you could construct an FPSCR value by ORing FPCR
and FPSR, or equivalently could produce FPSR and FPCR by masking an
FPSCR value.  For QEMU's implementation, we opted to use masking to
produce FPSR and FPCR, because we started with an AArch32
implementation of FPSCR.

The addition of the (AArch64-only) FEAT_AFP adds new bits to the FPCR
which overlap with some bits in the FPSR.  This means we'll no longer
be able to consider the FPSCR-encoded value as the primary one, but
instead need to treat FPSR/FPCR as the primary encoding and construct
the FPSCR from those.  (This remains possible because the FEAT_AFP
bits in FPCR don't appear in the FPSCR.)

As the first step in this refactoring, make vfp_get_fpscr() call
vfp_get_fpcr() and vfp_get_fpsr(), instead of the other way around.

Note that vfp_get_fpcsr_from_host() returns only bits in the FPSR
(for the cumulative fp exception bits), so we can simply rename
it without needing to add a new function for getting FPCR bits.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240628142347.1283015-3-peter.maydell@linaro.org
2024-07-11 11:41:33 +01:00
Peter Maydell
ea8618382a target/arm: Correct comments about M-profile FPSCR
The M-profile FPSCR LTPSIZE is bits [18:16]; this is the same
field as A-profile FPSCR Len, not Stride. Correct the comment
in vfp_get_fpscr().

We also implemented M-profile FPSCR.QC, but forgot to delete
a TODO comment from vfp_set_fpscr(); remove it now.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240628142347.1283015-2-peter.maydell@linaro.org
2024-07-11 11:41:33 +01:00
Richard Henderson
7619129f0d target/arm: Fix FJCVTZS vs flush-to-zero
Input denormals cause the Javascript inexact bit
(output to Z) to be set.

Cc: qemu-stable@nongnu.org
Fixes: 6c1f6f2733 ("target/arm: Implement ARMv8.3-JSConv")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2375
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240625183536.1672454-4-richard.henderson@linaro.org
[PMM: fixed hardcoded tab in test case]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2024-07-01 12:48:55 +01:00
Richard Henderson
21e885aff4 target/arm: Expand vfp neg and abs inline
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240524232121.284515-23-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2024-05-28 14:29:01 +01:00
Peter Maydell
5a534314a8 target/arm: Move feature test functions to their own header
The feature test functions isar_feature_*() now take up nearly
a thousand lines in target/arm/cpu.h. This header file is included
by a lot of source files, most of which don't need these functions.
Move the feature test functions to their own header file.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20231024163510.2972081-2-peter.maydell@linaro.org
2023-10-27 11:44:32 +01:00
Richard Henderson
34d03ad963 target/arm: Use float64_to_int32_modulo for FJCVTZS
The standard floating point results are provided by the generic routine.
We only need handle the extra Z flag result afterward.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230527141910.1885950-5-richard.henderson@linaro.org>
2023-07-01 08:26:54 +02:00
Richard Henderson
6ce21abd40 target/arm: Improve arm_rmode_to_sf
Use proper enumeration types for input and output.
Use a const array to perform the mapping, with an
assert that the input is valid.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-13 06:44:38 -07:00
Richard Henderson
ab9ced73fa target/arm: Handle FPROUNDING_ODD in arm_rmode_to_sf
While this enumerator has been present since the first commit,
it isn't ever used.  The first actual use of round-to-odd came
with SVE, which currently uses float_round_to_odd instead of
the arm-specific enumerator.

Amusingly, the comment about unhandled TIEAWAY has been
out of date since the initial commit of translate-a64.c.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-03-13 06:44:38 -07:00
Joe Komlodi
103e7579dd target/arm: Check NaN mode before silencing NaN
If the CPU is running in default NaN mode (FPCR.DN == 1) and we execute
FRSQRTE, FRECPE, or FRECPX with a signaling NaN, parts_silence_nan_frac() will
assert due to fpst->default_nan_mode being set.

To avoid this, we check to see what NaN mode we're running in before we call
floatxx_silence_nan().

Signed-off-by: Joe Komlodi <joe.komlodi@xilinx.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 1624662174-175828-2-git-send-email-joe.komlodi@xilinx.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-07-02 11:48:36 +01:00
Peter Maydell
c485ce2c49 target/arm: Enable FPSCR.QC bit for MVE
MVE has an FPSCR.QC bit similar to the A-profile Neon one; when MVE
is implemented make the bit writeable, both in the generic "load and
store FPSCR" helper functions and in the code for handling the NZCVQC
sysreg which we had previously left as "TODO when we implement MVE".

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-3-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Richard Henderson
d29b17ca3e target/arm: Implement vector float32 to bfloat16 conversion
This is BFCVT{N,T} for both AArch64 AdvSIMD and SVE,
and VCVT.BF16.F32 for AArch32 NEON.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210525225817.400336-5-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-06-03 16:43:26 +01:00
Richard Henderson
3a98ac40fa target/arm: Implement scalar float32 to bfloat16 conversion
This is the 64-bit BFCVT and the 32-bit VCVT{B,T}.BF16.F32.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210525225817.400336-4-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-06-03 16:43:26 +01:00
Peter Maydell
b26b5629c0 target/arm: Make FPSCR.LTPSIZE writable for MVE
The M-profile FPSCR has an LTPSIZE field, but if MVE is not
implemented it is read-only and always reads as 4; this is how QEMU
currently handles it.

Make the field writable when MVE is implemented.

We can safely add the field to the MVE migration struct because
currently no CPUs enable MVE and so the migration struct is never
used.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210520152840.24453-8-peter.maydell@linaro.org
2021-06-03 16:43:25 +01:00
Peter Maydell
8128c8e8cc target/arm: Implement FPSCR.LTPSIZE for M-profile LOB extension
If the M-profile low-overhead-branch extension is implemented, FPSCR
bits [18:16] are a new field LTPSIZE.  If MVE is not implemented
(currently always true for us) then this field always reads as 4 and
ignores writes.

These bits used to be the vector-length field for the old
short-vector extension, so we need to take care that they are not
misinterpreted as setting vec_len. We do this with a rearrangement
of the vfp_set_fpscr() code that deals with vec_len, vec_stride
and also the QC bit; this obviates the need for the M-profile
only masking step that we used to have at the start of the function.

We provide a new field in CPUState for LTPSIZE, even though this
will always be 4, in preparation for MVE, so we don't have to
come back later and split it out of the vfp.xregs[FPSCR] value.
(This state struct field will be saved and restored as part of
the FPSCR value via the vmstate_fpscr in machine.c.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20201019151301.2046-11-peter.maydell@linaro.org
2020-10-20 16:12:01 +01:00
Peter Maydell
d31e2ce68d target/arm: Allow M-profile CPUs with FP16 to set FPSCR.FP16
M-profile CPUs with half-precision floating point support should
be able to write to FPSCR.FZ16, but an M-profile specific masking
of the value at the top of vfp_set_fpscr() currently prevents that.
This is not yet an active bug because we have no M-profile
FP16 CPUs, but needs to be fixed before we can add any.

The bits that the masking is effectively preventing from being
set are the A-profile only short-vector Len and Stride fields,
plus the Neon QC bit. Rearrange the order of the function so
that those fields are handled earlier and only under a suitable
guard; this allows us to drop the M-profile specific masking,
making FZ16 writeable.

This change also makes the QC bit correctly RAZ/WI for older
no-Neon A-profile cores.

This refactoring also paves the way for the low-overhead-branch
LTPSIZE field, which uses some of the bits that are used for
A-profile Stride and Len.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20201019151301.2046-10-peter.maydell@linaro.org
2020-10-20 16:12:01 +01:00
Peter Maydell
61db12d9f9 target/arm: AArch32 VCVT fixed-point to float is always round-to-nearest
For AArch32, unlike the VCVT of integer to float, which honours the
rounding mode specified by the FPSCR, VCVT of fixed-point to float is
always round-to-nearest. (AArch64 fixed-point-to-float conversions
always honour the FPCR rounding mode.)

Implement this by providing _round_to_nearest versions of the
relevant helpers which set the rounding mode temporarily when making
the call to the underlying softfloat function.

We only need to change the VFP VCVT instructions, because the
standard- FPSCR value used by the Neon VCVT is always set to
round-to-nearest, so we don't need to do the extra work of saving
and restoring the rounding mode.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20201013103532.13391-1-peter.maydell@linaro.org
2020-10-20 16:12:00 +01:00
Peter Maydell
18725916b1 target/arm: Implement fp16 for Neon VRINT-with-specified-rounding-mode
Convert the Neon VRINT-with-specified-rounding-mode insns to gvec,
and use this to implement the fp16 versions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-41-peter.maydell@linaro.org
2020-09-01 11:45:20 +01:00
Peter Maydell
40fde72dda target/arm: Implement fp16 for Neon VRSQRTS
Convert the Neon VRSQRTS insn to using a gvec helper,
and use this to implement the fp16 case.

As with VRECPS, we adjust the phrasing of the new implementation
slightly so that the fp32 version parallels the fp16 one.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-35-peter.maydell@linaro.org
2020-09-01 11:38:13 +01:00
Peter Maydell
ac8c62c4e5 target/arm: Implement fp16 for Neon VRECPS
Convert the Neon VRECPS insn to using a gvec helper, and
use this to implement the fp16 case.

The phrasing of the new float32_recps_nf() is slightly different from
the old recps_f32() so that it parallels the f16 version; for f16 we
can't assume that flush-to-zero is always enabled.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-34-peter.maydell@linaro.org
2020-09-01 11:38:06 +01:00
Peter Maydell
0a6f4b4cb3 target/arm: Implement VFP fp16 VRINT*
Implement the fp16 version of the VFP VRINT* insns.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-19-peter.maydell@linaro.org
2020-09-01 11:19:32 +01:00
Peter Maydell
414ba270c4 target/arm: Use macros instead of open-coding fp16 conversion helpers
Now the VFP_CONV_FIX macros can handle fp16's distinction between the
width of the operation and the width of the type used to pass operands,
use the macros rather than the open-coded functions.

This creates an extra six helper functions, all of which we are going
to need for the AArch32 VFP fp16 instructions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-15-peter.maydell@linaro.org
2020-09-01 11:19:32 +01:00
Peter Maydell
5366f6ad7d target/arm: Make VFP_CONV_FIX macros take separate float type and float size
Currently the VFP_CONV_FIX macros take a single fsz argument for the
size of the float type, which is used both to select the name of
the functions to call (eg float32_is_any_nan()) and also for the
type to use for the float inputs and outputs (eg float32).

Separate these into fsz and ftype arguments, so that we can use them
for fp16, which uses 'float16' in the function names but is still
passing inputs and outputs in a 32-bit sized type.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-14-peter.maydell@linaro.org
2020-09-01 11:19:32 +01:00
Peter Maydell
1b88b054c5 target/arm: Implement VFP fp16 VCMP
Implement fp16 version of VCMP.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-11-peter.maydell@linaro.org
2020-09-01 11:19:32 +01:00
Peter Maydell
ce2d65a5d1 target/arm: Implement VFP fp16 for VABS, VNEG, VSQRT
Implement VFP fp16 for VABS, VNEG and VSQRT. This is all
the fp16 insns that use the DO_VFP_2OP macro, because there
is no fp16 version of VMOV_reg.

Notes:
 * the gen_helper_vfp_negh already exists as we needed to create
   it for the fp16 multiply-add insns
 * as usual we need to use the f16 version of the fp_status;
   this is only relevant for VSQRT

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-9-peter.maydell@linaro.org
2020-09-01 11:19:32 +01:00
Peter Maydell
9886fe2834 target/arm: Implement VFP fp16 for fused-multiply-add
Implement VFP fp16 support for fused multiply-add insns
VFNMA, VFNMS, VFMA, VFMS.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-7-peter.maydell@linaro.org
2020-09-01 11:19:32 +01:00
Peter Maydell
e7cb0ded52 target/arm: Implement VFP fp16 VMLA, VMLS, VNMLS, VNMLA, VNMUL
Implement fp16 versions of the VFP VMLA, VMLS, VNMLS, VNMLA, VNMUL
instructions. (These are all the remaining ones which we implement
via do_vfp_3op_[hsd]p().)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-5-peter.maydell@linaro.org
2020-09-01 11:19:32 +01:00
Peter Maydell
120a0eb3ea target/arm: Implement VFP fp16 for VFP_BINOP operations
Implmeent VFP fp16 support for simple binary-operator VFP insns VADD,
VSUB, VMUL, VDIV, VMINNM and VMAXNM:

 * make the VFP_BINOP() macro generate float16 helpers as well as
   float32 and float64
 * implement a do_vfp_3op_hp() function similar to the existing
   do_vfp_3op_sp()
 * add decode for the half-precision insn patterns

Note that the VFP_BINOP macro use creates a couple of unused helper
functions vfp_maxh and vfp_minh, but they're small so it's not worth
splitting the BINOP operations into "needs halfprec" and "no
halfprec" groups.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-4-peter.maydell@linaro.org
2020-09-01 11:19:32 +01:00
Peter Maydell
b684e49a17 target/arm: Remove local definitions of float constants
In several places the target/arm code defines local float constants
for 2, 3 and 1.5, which are also provided by include/fpu/softfloat.h.
Remove the unnecessary local duplicate versions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-2-peter.maydell@linaro.org
2020-09-01 11:19:32 +01:00
Peter Maydell
aaae563bc7 target/arm: Implement FPST_STD_F16 fpstatus
Architecturally, Neon FP16 operations use the "standard FPSCR" like
all other Neon operations.  However, this is defined in the Arm ARM
pseudocode as "a fixed value, except that FZ16 (and AHP) follow the
FPSCR bits". In QEMU, the softfloat float_status doesn't include
separate flush-to-zero for FP16 operations, so we must keep separate
fp_status for "Neon non-FP16" and "Neon fp16" operations, in the
same way we do already for the non-Neon "fp_status" vs "fp_status_f16".

Add the extra float_status field to the CPU state structure,
ensure it is correctly initialized and updated on FPSCR writes,
and make fpstatus_ptr(FPST_STD_F16) return a pointer to it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20200806104453.30393-4-peter.maydell@linaro.org
2020-08-24 10:15:11 +01:00
Richard Henderson
71bfd65c5f softfloat: Name compare relation enum
Give the previously unnamed enum a typedef name.  Use it in the
prototypes of compare functions.  Use it to hold the results
of the compare functions.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-05-19 08:41:45 -07:00
Richard Henderson
3dede407cc softfloat: Name rounding mode enum
Give the previously unnamed enum a typedef name.  Use the packed
attribute so that we do not affect the layout of the float_status
struct.  Use it in the prototypes of relevant functions.

Adjust switch statements as necessary to avoid compiler warnings.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-05-19 08:41:26 -07:00
Richard Henderson
c120391c00 softfloat: Replace flag with bool
We have had this on the to-do list for quite some time.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-05-19 08:40:50 -07:00
Peter Maydell
26c6f695cf target/arm: Move 'env' argument of recps_f32 and rsqrts_f32 helpers to usual place
The usual location for the env argument in the argument list of a TCG helper
is immediately after the return-value argument. recps_f32 and rsqrts_f32
differ in that they put it at the end.

Move the env argument to its usual place; this will allow us to
more easily use these helper functions with the gvec APIs.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200512163904.10918-16-peter.maydell@linaro.org
2020-05-14 15:03:09 +01:00
Richard Henderson
fe6fb4beb2 target/arm: Remove fp_status from helper_{recpe, rsqrte}_u32
These operations do not touch fp_status.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200513163245.17915-12-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-05-14 15:03:08 +01:00
Peter Maydell
6e61f8391c target/arm: Add isar_feature_any_fp16 and document naming/usage conventions
Our current usage of the isar_feature feature tests almost always
uses an _aa32_ test when the code path is known to be AArch32
specific and an _aa64_ test when the code path is known to be
AArch64 specific. There is just one exception: in the vfp_set_fpscr
helper we check aa64_fp16 to determine whether the FZ16 bit in
the FP(S)CR exists, but this code is also used for AArch32.
There are other places in future where we're likely to want
a general "does this feature exist for either AArch32 or
AArch64" check (typically where architecturally the feature exists
for both CPU states if it exists at all, but the CPU might be
AArch32-only or AArch64-only, and so only have one set of ID
registers).

Introduce a new category of isar_feature_* functions:
isar_feature_any_foo() should be tested when what we want to
know is "does this feature exist for either AArch32 or AArch64",
and always returns the logical OR of isar_feature_aa32_foo()
and isar_feature_aa64_foo().

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20200214175116.9164-4-peter.maydell@linaro.org
2020-02-21 16:07:00 +00:00
Marc Zyngier
9ca1d776cb target/arm: Handle trapping to EL2 of AArch32 VMRS instructions
HCR_EL2.TID3 requires that AArch32 reads of MVFR[012] are trapped to
EL2, and HCR_EL2.TID0 does the same for reads of FPSID.
In order to handle this, introduce a new TCG helper function that
checks for these control bits before executing the VMRC instruction.

Tested with a hacked-up version of KVM/arm64 that sets the control
bits for 32bit guests.

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20191201122018.25808-4-maz@kernel.org
[PMM: move helper declaration to helper.h; make it
 TCG_CALL_NO_WG]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-12-16 10:46:34 +00:00
Philippe Mathieu-Daudé
85795187f4 target/arm/vfp_helper: Call set_fpscr_to_host before updating to FPSCR
In commit e9d652824b we extracted the vfp_set_fpscr_to_host()
function but failed at calling it in the correct place, we call
it after xregs[ARM_VFP_FPSCR] is modified.

Fix by calling this function before we update FPSCR.

Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Tested-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Message-id: 20190705124318.1075-1-philmd@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-07-08 14:11:31 +01:00
Philippe Mathieu-Daudé
4a15527c9f target/arm/vfp_helper: Restrict the SoftFloat use to TCG
This code is specific to the SoftFloat floating-point
implementation, which is only used by TCG.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190701132516.26392-18-philmd@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-07-01 17:29:01 +01:00
Philippe Mathieu-Daudé
0c6ad94809 target/arm/vfp_helper: Extract vfp_set_fpscr_from_host()
The vfp_set_fpscr() helper contains code specific to the host
floating point implementation (here the SoftFloat library).
Extract this code to vfp_set_fpscr_from_host().

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190701132516.26392-17-philmd@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-07-01 17:29:01 +01:00
Philippe Mathieu-Daudé
e9d652824b target/arm/vfp_helper: Extract vfp_set_fpscr_to_host()
The vfp_set_fpscr() helper contains code specific to the host
floating point implementation (here the SoftFloat library).
Extract this code to vfp_set_fpscr_to_host().

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190701132516.26392-16-philmd@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-07-01 17:29:01 +01:00
Philippe Mathieu-Daudé
20e62dd8c8 target/arm/vfp_helper: Move code around
To ease the review of the next commit,
move the vfp_exceptbits_to_host() function directly after
vfp_exceptbits_from_host().  Amusingly the diff shows we
are moving vfp_get_fpscr().

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190701132516.26392-15-philmd@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-07-01 17:29:01 +01:00
Philippe Mathieu-Daudé
9798ac7162 target/arm: Fix coding style issues
Since we'll move this code around, fix its style first.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190701132516.26392-9-philmd@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-07-01 17:29:00 +01:00
Philippe Mathieu-Daudé
9a223097e4 target/arm: Fix multiline comment syntax
Since commit 8c06fbdf36 checkpatch.pl enforce a new multiline
comment syntax. Since we'll move this code around, fix its style
first.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190701132516.26392-8-philmd@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-07-01 17:29:00 +01:00