Commit Graph

113 Commits

Author SHA1 Message Date
Alex Bennée c13bb2da9e fpu/softfloat: re-factor sqrt
This is a little bit of a departure from softfloat's original approach
as we skip the estimate step in favour of a straight iteration. There
is a minor optimisation to avoid calculating more bits of precision
than we need however this still brings a performance drop, especially
for float64 operations.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21 10:21:54 +00:00
Alex Bennée 0c4c909291 fpu/softfloat: re-factor compare
The compare function was already expanded from a macro. I keep the
macro expansion but move most of the logic into a compare_decomposed.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21 10:21:47 +00:00
Alex Bennée 8936006707 fpu/softfloat: re-factor minmax
Let's do the same re-factor treatment for minmax functions. I still
use the MACRO trick to expand but now all the checking code is common.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21 10:21:41 +00:00
Alex Bennée 0bfc9f1952 fpu/softfloat: re-factor scalbn
This is one of the simpler manipulations you could make to a floating
point number.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21 10:21:34 +00:00
Alex Bennée c02e1fb80b fpu/softfloat: re-factor int/uint to float
These are considerably simpler as the lower order integers can just
use the higher order conversion function. As the decomposed fractional
part is a full 64 bit rounding and inexact handling comes from the
pack functions.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21 10:21:29 +00:00
Alex Bennée ab52f973a5 fpu/softfloat: re-factor float to int/uint
We share the common int64/uint64_pack_decomposed function across all
the helpers and simply limit the final result depending on the final
size.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-02-21 10:21:22 +00:00
Alex Bennée dbe4d53a59 fpu/softfloat: re-factor round_to_int
We can now add float16_round_to_int and use the common round_decomposed and
canonicalize functions to have a single implementation for
float16/32/64 round_to_int functions.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21 10:21:16 +00:00
Alex Bennée d446830a3a fpu/softfloat: re-factor muladd
We can now add float16_muladd and use the common decompose and
canonicalize functions to have a single implementation for
float16/32/64 muladd functions.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21 10:21:11 +00:00
Alex Bennée cf07323d49 fpu/softfloat: re-factor div
We can now add float16_div and use the common decompose and
canonicalize functions to have a single implementation for
float16/32/64 versions.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21 10:21:06 +00:00
Alex Bennée 74d707e2cc fpu/softfloat: re-factor mul
We can now add float16_mul and use the common decompose and
canonicalize functions to have a single implementation for
float16/32/64 versions.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21 10:20:59 +00:00
Alex Bennée 6fff216769 fpu/softfloat: re-factor add/sub
We can now add float16_add/sub and use the common decompose and
canonicalize functions to have a single implementation for
float16/32/64 add and sub functions.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2018-02-21 10:20:53 +00:00
Alex Bennée a90119b5a2 fpu/softfloat: define decompose structures
These structures pave the way for generic softfloat helper routines
that will operate on fully decomposed numbers.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2018-02-21 10:20:45 +00:00
Alex Bennée d97544c94a fpu/softfloat: move the extract functions to the top of the file
This is pure code-motion during re-factoring as the helpers will be
needed earlier.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21 10:20:39 +00:00
Alex Bennée 210cbd4910 fpu/softfloat: implement float16_squash_input_denormal
This will be required when expanding the MINMAX() macro for 16
bit/half-precision operations.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2018-02-21 10:20:14 +00:00
Laurent Vivier 0f72129281 softfloat: define floatx80_round()
Add a function to round a floatx80 to the defined precision
(floatx80_rounding_precision)

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Message-Id: <20170628204241.32106-5-laurent@vivier.eu>
2017-06-29 20:27:39 +02:00
Peter Maydell d000b477f2 softfloat: Use correct type in float64_to_uint64_round_to_zero()
In float64_to_uint64_round_to_zero() a typo meant that we were
taking the uint64_t return value from float64_to_uint64() and
putting it into an int64_t variable before returning it as
uint64_t again. Use uint64_t instead of pointlessly casting it
back and forth to int64_t.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2017-02-28 09:03:38 +03:00
Bharata B Rao fd425037d2 softfloat: Add float128_to_uint32_round_to_zero()
float128_to_uint32_round_to_zero() is needed by xscvqpuwz instruction
of PowerPC ISA 3.0.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2017-02-22 11:28:28 +11:00
Bharata B Rao 2e6d856835 softfloat: Add float128_to_uint64_round_to_zero()
Implement float128_to_uint64() and use that to implement
float128_to_uint64_round_to_zero()

This is required by xscvqpudz instruction of PowerPC ISA 3.0.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2017-02-22 11:28:28 +11:00
Bharata B Rao 9ee6f678f4 softfloat: Add round-to-odd rounding mode
Power ISA 3.0 introduces a few quadruple precision floating point
instructions that support round-to-odd rounding mode. The
round-to-odd mode is explained as under:

Let Z be the intermediate arithmetic result or the operand of a convert
operation. If Z can be represented exactly in the target format, the
result is Z. Otherwise the result is either Z1 or Z2 whichever is odd.
Here Z1 and Z2 are the next larger and smaller numbers representable
in the target format respectively.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2017-02-22 11:28:28 +11:00
Andrew Dutcher d1eb8f2acb fpu: add mechanism to check for invalid long double formats
All operations that take a floatx80 as an operand need to have their
inputs checked for malformed encodings. In all of these cases, use the
function floatx80_invalid_encoding to perform the check. If an invalid
operand is found, raise an invalid operation exception, and then return
either NaN (for fp-typed results) or the integer indefinite value (the
minimum representable signed integer value, for int-typed results).

For the non-quiet comparison operations, this touches adjacent code in
order to pass style checks.

Signed-off-by: Andrew Dutcher <andrew@andrewdutcher.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1471392895-17324-1-git-send-email-andrew@andrewdutcher.com
[PMM: changed "1 << 63" to "1ULL << 63" to fix compile errors]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-09-15 12:43:18 +01:00
Aleksandar Markovic af39bc8c49 softfloat: Implement run-time-configurable meaning of signaling NaN bit
This patch modifies SoftFloat library so that it can be configured in
run-time in relation to the meaning of signaling NaN bit, while, at the
same time, strictly preserving its behavior on all existing platforms.

Background:

In floating-point calculations, there is a need for denoting undefined or
unrepresentable values. This is achieved by defining certain floating-point
numerical values to be NaNs (which stands for "not a number"). For additional
reasons, virtually all modern floating-point unit implementations use two
kinds of NaNs: quiet and signaling. The binary representations of these two
kinds of NaNs, as a rule, differ only in one bit (that bit is, traditionally,
the first bit of mantissa).

Up to 2008, standards for floating-point did not specify all details about
binary representation of NaNs. More specifically, the meaning of the bit
that is used for distinguishing between signaling and quiet NaNs was not
strictly prescribed. (IEEE 754-2008 was the first floating-point standard
that defined that meaning clearly, see [1], p. 35) As a result, different
platforms took different approaches, and that presented considerable
challenge for multi-platform emulators like QEMU.

Mips platform represents the most complex case among QEMU-supported
platforms regarding signaling NaN bit. Up to the Release 6 of Mips
architecture, "1" in signaling NaN bit denoted signaling NaN, which is
opposite to IEEE 754-2008 standard. From Release 6 on, Mips architecture
adopted IEEE standard prescription, and "0" denotes signaling NaN. On top of
that, Mips architecture for SIMD (also known as MSA, or vector instructions)
also specifies signaling bit in accordance to IEEE standard. MSA unit can be
implemented with both pre-Release 6 and Release 6 main processor units.

QEMU uses SoftFloat library to implement various floating-point-related
instructions on all platforms. The current QEMU implementation allows for
defining meaning of signaling NaN bit during build time, and is implemented
via preprocessor macro called SNAN_BIT_IS_ONE.

On the other hand, the change in this patch enables SoftFloat library to be
configured in run-time. This configuration is meant to occur during CPU
initialization, at the moment when it is definitely known what desired
behavior for particular CPU (or any additional FPUs) is.

The change is implemented so that it is consistent with existing
implementation of similar cases. This means that structure float_status is
used for passing the information about desired signaling NaN bit on each
invocation of SoftFloat functions. The additional field in float_status is
called snan_bit_is_one, which supersedes macro SNAN_BIT_IS_ONE.

IMPORTANT:

This change is not meant to create any change in emulator behavior or
functionality on any platform. It just provides the means for SoftFloat
library to be used in a more flexible way - in other words, it will just
prepare SoftFloat library for usage related to Mips platform and its
specifics regarding signaling bit meaning, which is done in some of
subsequent patches from this series.

Further break down of changes:

  1) Added field snan_bit_is_one to the structure float_status, and
     correspondent setter function set_snan_bit_is_one().

  2) Constants <float16|float32|float64|floatx80|float128>_default_nan
     (used both internally and externally) converted to functions
     <float16|float32|float64|floatx80|float128>_default_nan(float_status*).
     This is necessary since they are dependent on signaling bit meaning.
     At the same time, for the sake of code cleanup and simplicity, constants
     <floatx80|float128>_default_nan_<low|high> (used only internally within
     SoftFloat library) are removed, as not needed.

  3) Added a float_status* argument to SoftFloat library functions
     XXX_is_quiet_nan(XXX a_), XXX_is_signaling_nan(XXX a_),
     XXX_maybe_silence_nan(XXX a_). This argument must be present in
     order to enable correct invocation of new version of functions
     XXX_default_nan(). (XXX is <float16|float32|float64|floatx80|float128>
     here)

  4) Updated code for all platforms to reflect changes in SoftFloat library.
     This change is twofolds: it includes modifications of SoftFloat library
     functions invocations, and an addition of invocation of function
     set_snan_bit_is_one() during CPU initialization, with arguments that
     are appropriate for each particular platform. It was established that
     all platforms zero their main CPU data structures, so snan_bit_is_one(0)
     in appropriate places is not added, as it is not needed.

[1] "IEEE Standard for Floating-Point Arithmetic",
    IEEE Computer Society, August 29, 2008.

Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Tested-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Tested-by: Leon Alrae <leon.alrae@imgtec.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[leon.alrae@imgtec.com:
 * cherry-picked 2 chunks from patch #2 to fix compilation warnings]
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
2016-06-24 13:40:37 +01:00
Peter Maydell 0c48262d47 fpu: Use plain 'int' rather than 'int_fast16_t' for exponents
Use the plain 'int' type rather than 'int_fast16_t' for handling
exponents. Exponents don't need to be exactly 16 bits, so using int16_t
for them would confuse more than it clarified.

This should be a safe change because int_fast16_t semantics
permit use of 'int' (and on 32-bit glibc that is what you get).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Message-id: 1453807806-32698-4-git-send-email-peter.maydell@linaro.org
2016-02-19 16:27:22 +00:00
Peter Maydell 07d792d2b0 fpu: Use plain 'int' rather than 'int_fast16_t' for shift counts
Use the plain 'int' type rather than 'int_fast16_t' for shift counts
in the various shift related functions, since we don't actually care
about the size of the integer at all here, and using int16_t would
be confusing.

This should be a safe change because int_fast16_t semantics
permit use of 'int' (and on 32-bit glibc that is what you get).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Message-id: 1453807806-32698-3-git-send-email-peter.maydell@linaro.org
2016-02-19 16:27:22 +00:00
Peter Maydell 0bb721d721 fpu: Remove use of int_fast16_t in conversions to int16
Make the functions which convert floating point to 16 bit integer
return int16_t rather than int_fast16_t, and correspondingly use
int_fast16_t in their internal implementations where appropriate.

(These functions are used only by the ARM target.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Message-id: 1453807806-32698-2-git-send-email-peter.maydell@linaro.org
2016-02-19 16:27:21 +00:00
Peter Maydell d38ea87ac5 all: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1454089805-5470-16-git-send-email-peter.maydell@linaro.org
2016-02-04 17:41:30 +00:00
Aurelien Jarno 7ceac86f49 softfloat: fix return type of roundAndPackFloat16
The roundAndPackFloat16 function should return a float16 value, not a
float32 one. Fix that.

Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1452700993-6570-1-git-send-email-aurelien@aurel32.net
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-01-22 15:09:21 +00:00
Peter Maydell 8f506c709a fpu: Replace int8 typedef with int8_t
Replace the int8 softfloat-specific typedef with int8_t.
This change was made with

find include hw fpu target-* -name '*.[ch]' | xargs sed -i -e 's/\bint8\b/int8_t/g'

together with manual removal of the typedef definition, and
manual undoing of various mis-hits.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: Leon Alrae <leon.alrae@imgtec.com>
Acked-by: James Hogan <james.hogan@imgtec.com>
Message-id: 1452603315-27030-6-git-send-email-peter.maydell@linaro.org
2016-01-22 15:09:21 +00:00
Peter Maydell 3a87d00910 fpu: Replace uint32 typedef with uint32_t
Replace the uint32 softfloat-specific typedef with uint32_t.
This change was made with

find include hw fpu target-* -name '*.[ch]' | xargs sed -i -e 's/\buint32\b/uint32_t/g'

together with manual removal of the typedef definition,
manual undoing of various mis-hits, and another couple of
fixes found via test compilation.

All the uses in hw/ were using the wrong type by mistake.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: Leon Alrae <leon.alrae@imgtec.com>
Acked-by: James Hogan <james.hogan@imgtec.com>
Message-id: 1452603315-27030-5-git-send-email-peter.maydell@linaro.org
2016-01-22 15:09:21 +00:00
Peter Maydell f4014512cd fpu: Replace int32 typedef with int32_t
Replace the int32 softfloat-specific typedef with int32_t.
This change was made with

find hw include fpu target-* -name '*.[ch]' | xargs sed -i -e 's/\bint32\b/int32_t/g'

together with manual removal of the typedef definition, and
manual undoing of some mis-hits where macro arguments were
being used for token pasting rather than as a type.

The uses in hw/ipmi/ should not have been using this type at all.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: Leon Alrae <leon.alrae@imgtec.com>
Acked-by: James Hogan <james.hogan@imgtec.com>
Message-id: 1452603315-27030-4-git-send-email-peter.maydell@linaro.org
2016-01-22 15:09:21 +00:00
Peter Maydell 182f42fdc2 fpu: Replace uint64 typedef with uint64_t
Replace the uint64 softfloat-specific typedef with uint64_t.
This change was made with

find include fpu target-* -name '*.[ch]' | xargs sed -i -e 's/\buint64\b/uint64_t/g'

together with manual removal of the typedef definition, and
manual undoing of some mis-hits where macro arguments were
being used for token pasting rather than as a type.

Note that the target-mips/kvm.c and target-s390x/kvm.c changes are fixing
code that should not have been using the uint64 type in the first place.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: Leon Alrae <leon.alrae@imgtec.com>
Acked-by: James Hogan <james.hogan@imgtec.com>
Message-id: 1452603315-27030-3-git-send-email-peter.maydell@linaro.org
2016-01-22 15:09:20 +00:00
Peter Maydell f42c222482 fpu: Replace int64 typedef with int64_t
Replace the int64 softfloat-specific typedef with int64_t.
This change was made with

find include fpu target-* -name '*.[ch]' | xargs sed -i -e 's/\bint64\b/int64_t/g'

together with manual removal of the typedef definition, and
manual undoing of some mis-hits where macro arguments were
being used for token pasting rather than as a type.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: Leon Alrae <leon.alrae@imgtec.com>
Message-id: 1452603315-27030-2-git-send-email-peter.maydell@linaro.org
2016-01-22 15:09:20 +00:00
Peter Maydell a2f2d288b5 softfloat: expand out STATUS macro
Expand out and remove the STATUS macro.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2015-02-06 16:11:38 +00:00
Peter Maydell ff32e16e86 softfloat: expand out STATUS_VAR
Expand out and remove the STATUS_VAR macro.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2015-02-06 16:11:38 +00:00
Peter Maydell e5a41ffa87 softfloat: Expand out the STATUS_PARAM macro
Expand out STATUS_PARAM wherever it is used and delete the definition.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2015-02-06 16:11:38 +00:00
Peter Maydell 16017c4854 softfloat: Clarify license status
The code in the softfloat source files is under a mixture of
licenses: the original code and many changes from QEMU contributors
are under the base SoftFloat-2a license; changes from Stefan Weil
and RedHat employees are GPLv2-or-later; changes from Fabrice Bellard
are under the BSD license. Clarify this in the comments at the
top of each affected source file, including a statement about
the assumed licensing for future contributions, so we don't need
to remember to ask patch submitters explicitly to pick a license.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Acked-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: Avi Kivity <avi.kivity@gmail.com>
Acked-by: Ben Taylor <bentaylor.solx86@gmail.com>
Acked-by: Blue Swirl <blauwirbel@gmail.com>
Acked-by: Christophe Lyon <christophe.lyon@st.com>
Acked-by: Fabrice Bellard <fabrice@bellard.org>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Juan Quintela <quintela@redhat.com>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Paul Brook <paul@codesourcery.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Richard Henderson <rth@twiddle.net>
Acked-by: Richard Sandiford <rdsandiford@googlemail.com>
Acked-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1421073508-23909-5-git-send-email-peter.maydell@linaro.org
2015-01-29 16:45:45 +00:00
Peter Maydell 6bb8e0f130 softfloat: Revert and reimplement remaining portions of 75d62a5856 and 3430b0be36
Revert the remaining portions of commits 75d62a5856 and 3430b0be36
which are under a SoftFloat-2b license, ie the functions
uint64_to_float32() and uint64_to_float64(). (The float64_to_uint64()
and float64_to_uint64_round_to_zero() functions were completely
rewritten in commits fb3ea83aa and 0a87a3107d so can stay.)

Reimplement from scratch the uint64_to_float64() and uint64_to_float32()
conversion functions.

[This is a mechanical squashing together of two separate "revert"
and "reimplement" patches.]

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1421073508-23909-3-git-send-email-peter.maydell@linaro.org
2015-01-29 15:05:28 +00:00
Peter Maydell a7d1ac78e0 softfloat: Apply patch corresponding to rebasing to softfloat-2a
This commit applies the changes to master which correspond to
replacing commit 158142c2c2 with a set of changes made by:
 * taking the SoftFloat-2a release
 * mechanically transforming the block comment style
 * reapplying Fabrice's original changes from 158142c2c2

This commit was created by:
 diff -u 158142c2c2 import-sf-2a
 patch  -p1 --fuzz 10 <../relicense-patch.txt
(where import-sf-2a is the branch resulting from the changes above).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1421073508-23909-2-git-send-email-peter.maydell@linaro.org
2015-01-29 15:05:28 +00:00
Leon Alrae 2d31e0607d softfloat: add functions corresponding to IEEE-2008 min/maxNumMag
Add abs argument to the existing softfloat minmax() function and define
new float{32,64}_{min,max}nummag functions.

minnummag(x,y) returns x if |x| < |y|,
               returns y if |y| < |x|,
               otherwise minnum(x,y)

maxnummag(x,y) returns x if |x| > |y|,
               returns y if |y| > |x|,
               otherwise maxnum(x,y)

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
2014-10-14 13:28:51 +01:00
Luiz Capitulino a49db98d1f fpu: softfloat: drop INLINE macro
This commit expands all uses of the INLINE macro and drop it.

The reason for this is to avoid clashes with external libraries with
bad name conventions and also because renaming keywords is not a good
practice.

PS: I'm fine with this change to be licensed under softfloat-2a or
softfloat-2b.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-06-23 11:00:12 -04:00
Tom Musta a13d448968 softfloat: Introduce float32_to_uint64_round_to_zero
This change adds the float32_to_uint64_round_to_zero function to the softfloat
library.  This function fills out the complement of float32 to INT round-to-zero
conversion rountines, where INT is {int32_t, uint32_t, int64_t, uint64_t}.

This contribution can be licensed under either the softfloat-2a or -2b
license.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Tested-by: Tom Musta <tommusta@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-04-08 11:20:00 +02:00
Alex Bennée 7baeabce1d softfloat: export squash_input_denormal functions
I need these available outside of softfloat for some of the reciprocal
processing in aarch64 helper functions.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-id: 1394822294-14837-20-git-send-email-peter.maydell@linaro.org
2014-03-17 16:31:51 +00:00
Peter Maydell 67d43538ae softfloat: Support halving the result of muladd operation
The ARMv8 instruction set includes a fused floating point
reciprocal square root step instruction which demands an
"(x * y + z) / 2" fused operation. Support this by adding
a flag to the softfloat muladd operations which requests
that the result is halved before rounding.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2014-02-20 10:35:50 +00:00
Peter Maydell f9288a76f1 softfloat: Add support for ties-away rounding
IEEE754-2008 specifies a new rounding mode:

"roundTiesToAway: the floating-point number nearest to the infinitely
precise result shall be delivered; if the two nearest floating-point
numbers bracketing an unrepresentable infinitely precise result are
equally near, the one with larger magnitude shall be delivered."

Implement this new mode (it is needed for ARM). The general principle
is that the required code is exactly like the ties-to-even code,
except that we do not need to do the "in case of exact tie clear LSB
to round-to-even", because the rounding operation naturally causes
the exact tie to round up in magnitude.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2014-01-08 19:07:22 +00:00
Peter Maydell dc355b764d softfloat: Refactor code handling various rounding modes
Refactor the code in various functions which calculates rounding
increments given the current rounding mode, so that instead of a
set of nested if statements we have a simple switch statement.
This will give us a clean place to add the case for the new
tiesAway rounding mode.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2014-01-08 19:07:22 +00:00
Peter Maydell 14c9a07eb9 softfloat: Add float16 <=> float64 conversion functions
Add the conversion functions float16_to_float64() and
float64_to_float16(), which will be needed for the ARM
A64 instruction set.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2014-01-08 19:07:22 +00:00
Peter Maydell c4a1c5e7e2 softfloat: Factor out RoundAndPackFloat16 and NormalizeFloat16Subnormal
In preparation for adding conversions between float16 and float64,
factor out code currently done inline in the float16<=>float32
conversion functions into functions RoundAndPackFloat16 and
NormalizeFloat16Subnormal along the lines of the existing versions
for the other float types.

Note that we change the handling of zExp from the inline code
to match the API of the other RoundAndPackFloat functions; however
we leave the positioning of the binary point between bits 22 and 23
rather than shifting it up to the high end of the word.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2014-01-08 19:07:22 +00:00
Peter Maydell 879d096b37 softfloat: Provide complete set of accessors for fp state
Tidy up the get/set accessors for the fp state to add missing ones
and make them all inline in softfloat.h rather than some inline and
some not.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2014-01-08 19:07:22 +00:00
Tom Musta fd728f2f94 softfloat: Fix float64_to_uint32_round_to_zero
The float64_to_uint32_round_to_zero routine is incorrect.

For example, the following test pattern:

    425F81378DC0CD1F / 0x1.f81378dc0cd1fp+38

will erroneously set the inexact flag.

This patch re-implements the routine to use the float64_to_uint64_round_to_zero
routine.  If saturation occurs we ignore any flags set by the
conversion function and raise only Invalid.

This contribution can be licensed under either the softfloat-2a or -2b
license.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Message-id: 1387397961-4894-6-git-send-email-tommusta@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2014-01-08 19:07:22 +00:00
Tom Musta 5e7f654fa1 softfloat: Fix float64_to_uint32
The float64_to_uint32 has several flaws:

 - for numbers between 2**32 and 2**64, the inexact exception flag
   may get incorrectly set.  In this case, only the invalid flag
   should be set.

       test pattern: 425F81378DC0CD1F / 0x1.f81378dc0cd1fp+38

 - for numbers between 2**63 and 2**64, incorrect results may
   be produced:

       test pattern: 43EAAF73F1F0B8BD / 0x1.aaf73f1f0b8bdp+63

This patch re-implements float64_to_uint32 to re-use the
float64_to_uint64 routine (instead of float64_to_int64).  For the
saturation case, we ignore any flags which the conversion routine
has set and raise only the invalid flag.

This contribution can be licensed under either the softfloat-2a or -2b
license.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Message-id: 1387397961-4894-5-git-send-email-tommusta@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2014-01-08 19:07:22 +00:00
Tom Musta 0a87a3107d softfloat: Fix float64_to_uint64_round_to_zero
The float64_to_uint64_round_to_zero routine is incorrect.

For example, the following test pattern:

    46697351FF4AEC29 / 0x1.97351ff4aec29p+103

currently produces 8000000000000000 instead of FFFFFFFFFFFFFFFF.

This patch re-implements the routine to temporarily force the
rounding mode and use the float64_to_uint64 routine.

This contribution can be licensed under either the softfloat-2a or -2b
license.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Message-id: 1387397961-4894-4-git-send-email-tommusta@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2014-01-08 19:07:22 +00:00