Commit Graph

6 Commits

Author SHA1 Message Date
Joseph Myers
eb65a3d545 Remove some math_private.h libc_feholdexcept_setround overrides.
math_private.h headers for configurations lacking support for
floating-point exceptions and rounding modes define
libc_feholdexcept_setround to override the default version with one
that discards its rounding mode argument.

Unlike other such libc_fe* macros that I removed, this one is actually
used for such configurations (in dbl-64/e_sqrt.c).  However, this does
not make the macro required.  It's only used for such configurations
with FE_TONEAREST as the rounding mode (anything needing another mode
should not be used when that mode is unavailable), and the default
definition just calls __feholdexcept and __fesetround.  Since we now
have suitable inline do-nothing definitions of __feholdexcept and
__fesetround for the cases of no exceptions and rounding modes, we can
just rely on those inlines to achieve the same optimization as this
macro definition.  Thus, this patch removes those macro definitions
(and the math_private.h headers containing them, when no longer needed
after that removal).

Tested with build-many-glibcs.py that installed stripped shared
libraries are unchanged by the patch.

	* sysdeps/m68k/coldfire/fpu/math_private.h: Move to ....
	* sysdeps/m68k/coldfire/math_private.h: ... here.
	* sysdeps/m68k/coldfire/nofpu/math_private.h: Remove file.
	* sysdeps/tile/math_private.h: Likewise.
	* sysdeps/microblaze/math_private.h (libc_feholdexcept_setround):
	Remove macro.
	* sysdeps/nios2/math_private.h (libc_feholdexcept_setround):
	Likewise.
2018-02-01 20:58:57 +00:00
Joseph Myers
8a6bb1d086 Remove some math_private.h libc_fe* overrides.
math_private.h headers for configurations lacking support for
floating-point exceptions and rounding modes define various libc_fe*
macros to override the default versions with ones that discard any
exception or rounding mode arguments.

Three of the four macros defined in these headers are no longer needed
there: those macros are only used in fma implementations that are not
used for such configurations, now all those configurations properly
use soft-fp fma implementations instead.  (Effectively, those macros
were a workaround to allow glibc to build in the absence of a proper
fma implementation for this case - now there is such an
implementation, there is no need to support building the wrong
implementation for those configurations.)  Thus, this patch removes
the unnecessary macros.

Tested with build-many-glibcs.py that installed stripped shared
libraries are unchanged by the patch.

	* sysdeps/m68k/coldfire/nofpu/math_private.h (libc_fesetround):
	Remove macro.
	(libc_fetestexcept): Likewise.
	(libc_feupdateenv_test): Likewise.
	* sysdeps/microblaze/math_private.h (libc_fesetround): Likewise.
	(libc_fetestexcept): Likewise.
	(libc_feupdateenv_test): Likewise.
	* sysdeps/nios2/math_private.h (libc_fesetround): Likewise.
	(libc_fetestexcept): Likewise.
	(libc_feupdateenv_test): Likewise.
	* sysdeps/tile/math_private.h (libc_fesetround): Likewise.
	(libc_fetestexcept): Likewise.
	(libc_feupdateenv_test): Likewise.
2018-02-01 20:57:22 +00:00
Joseph Myers
d23a4962bb Move some fenv.h override macros to generic math_private.h.
Various configurations lacking support for floating-point exceptions
and rounding modes have a math_private.h that overrides certain
functions and macros, internal and external, to avoid references to
FE_* constants that are undefined in those configurations.  For
example, there are unconditional feraiseexcept (FE_INVALID) calls in
generic libm code, and these macro definitions duly define
feraiseexcept to ignore its argument to avoid an error from FE_INVALID
being undefined.

In fact it is easy to tell in an architecture-independent way whether
this is needed, by testing whether FE_ALL_EXCEPT == 0.  Thus, this
patch puts such a test, and feraiseexcept and __feraiseexcept macros,
in the generic math_private.h, so reducing the duplication between
architecture versions of this header.  The feclearexcept macro present
in several versions of this header, and fetestexcept in the tile
version, are not needed; they would have been needed before there were
proper soft-fp fma implementations (when generic versions, that depend
on FE_TOWARDZERO and FE_INEXACT, were being used for configurations
not supporting those features), but aren't needed any more, and so are
removed.

The tile version of this header has several inline functions for
fenv.h functions to optimize calls to them away in such configurations
where they do nothing useful, and all these header versions also have
definitions of some of the libc_fe* internal macros.  I intend to make
those generic in subsequent patches.

Tested with build-many-glibcs.py that installed stripped shared
libraries are unchanged by this patch.

	* sysdeps/generic/math_private.h [FE_ALL_EXCEPT == 0]
	(feraiseexcept): New macro.
	[FE_ALL_EXCEPT == 0] (__feraiseexcept): Likewise.
	* sysdeps/m68k/coldfire/nofpu/math_private.h (feraiseexcept):
	Remove macro.
	(__feraiseexcept): Likewise.
	(feclearexcept): Likewise.
	* sysdeps/microblaze/math_private.h (feraiseexcept): Likewise.
	(__feraiseexcept): Likewise.
	(feclearexcept): Likewise.
	* sysdeps/nios2/math_private.h (feraiseexcept): Likewise.
	(__feraiseexcept): Likewise.
	(feclearexcept): Likewise.
	* sysdeps/tile/math_private.h (feraiseexcept): Likewise.
	(__feraiseexcept): Likewise.
	(feclearexcept): Likewise.
	(fetestexcept): Likewise.
2018-02-01 20:52:59 +00:00
Joseph Myers
d4c7e1d0fd Add no-FPU ColdFire math_private.h.
As with some other soft-float configurations, no-FPU ColdFire needs
various fenv.h functions and glibc-internal macros overridden in
math_private.h to avoid references to undefined FE_* macros when
building glibc.  This patch adds a suitable math_private.h, based on
the MicroBlaze one (Nios II and Tile also have similar files).

There's a case for having such a file in sysdeps/ieee754/soft-fp so
this logic is applied more generally to configurations without
exceptions and rounding modes, even when the relevant macros are
defined in fenv.h - the only case where that might be inappropriate is
ARM soft-float (where the fenv.h functions might or might not work at
runtime, depending on whether the processor used at runtime supports
VFP).  There's also a case that soft-float configurations (on
processors with both hard-float and soft-float) should more
consistently avoid defining FE_* macros in bits/fenv.h when not
actually supported.  But both of those are separate potential
cleanups.

This allows the no-FPU ColdFire build to get further (another fix is
needed to allow the build to complete).

	* sysdeps/m68k/coldfire/nofpu/math_private.h: New file.  Based on
	MicroBlaze file.
2018-01-24 23:33:03 +00:00
Joseph Myers
6f7c009282 Add sysdeps/ieee754/soft-fp.
The default sysdeps/ieee754 fma implementations rely on exceptions and
rounding modes to achieve correct results through internal use of
round-to-odd.  Thus, glibc configurations without support for
exceptions and rounding modes instead need to use implementations of
fma based on soft-fp.

At present, this is achieved via having implementation files in
soft-fp/ that are #included by sysdeps files for each glibc
configuration that needs them.  In general this means such a
configuration has its own s_fma.c and s_fmaf.c.

TS 18661-1 adds functions that do an operation (+ - * / sqrt fma) on
arguments wider than the return type, with a single rounding of the
infinite-precision result to that return type.  These are also
naturally implemented using round-to-odd on platforms with hardware
support for rounding modes and exceptions but lacking hardware support
for these narrowing operations themselves.  (Platforms that have
direct hardware support for such narrowing operations include at least
ia64, and Power ISA 2.07 or later, which I think means POWER8 or
later.)

So adding the remaining TS 18661-1 functions would mean at least six
narrowing function implementations (fadd fsub fmul fdiv ffma fsqrt),
with aliases for other types and further implementations in some
configurations, that need to be overridden for configurations lacking
hardware exceptions and rounding modes.  Requiring all such
configurations (currently seven of them) to have their own source
files for all those functions seems undesirable.

Thus, this patch adds a directory sysdeps/ieee754/soft-fp to contain
libm function implementations based on soft-fp.  This directory is
then used via Implies from all the configurations that need it, so no
more files need adding to every such configuration when adding more
functions with soft-fp implementations.  A configuration can still
selectively #include a particular file from this directory if desired;
thus, the MIPS #include of the fmal implementation is retained, since
that's appropriate even for hard float (because long double is always
implementated in software for MIPS64, so the soft-fp implementation of
fmal is better than the ldbl-128 one).

This also provides additional motivation for my recent patch removing
--with-fp / --without-fp: previously there was no need for correct use
of --without-fp for no-FPU ARM or SH3, and now we have autodetection
nofpu/ sysdeps directories can be used by this patch for those
configurations without imposing any new requirements on how glibc is
configured.

(The mips64/*/fpu/s_fma.c files added by this patch are needed to keep
the dbl-64 version of fma for double, rather than the ldbl-128 one,
used in that case.)

Tested with build-many-glibcs.py that installed stripped shared
libraries are unchanged by this patch.

	* soft-fp/fmadf4.c: Move to ....
	* sysdeps/ieee754/soft-fp/s_fma.c: ... here.
	* soft-fp/fmasf4.c: Move to ....
	* sysdeps/ieee754/soft-fp/s_fmaf.c: ... here.
	* soft-fp/fmatf4.c: Move to ....
	* sysdeps/ieee754/soft-fp/s_fmal.c: ... here.
	* sysdeps/ieee754/soft-fp/Makefile: New file.
	* sysdeps/arm/preconfigure.ac: Define with_fp_cond.
	* sysdeps/arm/preconfigure: Regenerated.
	* sysdeps/arm/nofpu/Implies: New file.
	* sysdeps/arm/s_fma.c: Remove file.
	* sysdeps/arm/s_fmaf.c: Likewise.
	* sysdeps/m68k/coldfire/nofpu/Implies: New file.
	* sysdeps/m68k/coldfire/nofpu/s_fma.c: Remove file.
	* sysdeps/m68k/coldfire/nofpu/s_fmaf.c: Likewise.
	* sysdeps/microblaze/Implies: Add ieee754/soft-fp.
	* sysdeps/microblaze/s_fma.c: Remove file.
	* sysdeps/microblaze/s_fmaf.c: Likewise.
	* sysdeps/mips/mips32/nofpu/Implies: New file.
	* sysdeps/mips/mips64/n32/fpu/s_fma.c: Likewise.
	* sysdeps/mips/mips64/n32/nofpu/Implies: Likewise.
	* sysdeps/mips/mips64/n64/fpu/s_fma.c: Likewise.
	* sysdeps/mips/mips64/n64/nofpu/Implies: Likewise.
	* sysdeps/mips/ieee754/s_fma.c: Remove file.
	* sysdeps/mips/ieee754/s_fmaf.c: Likewise.
	* sysdeps/mips/ieee754/s_fmal.c: Update include for move of fmal
	implementation.
	* sysdeps/nios2/Implies: Add ieee754/soft-fp.
	* sysdeps/nios2/s_fma.c: Remove file.
	* sysdeps/nios2/s_fmaf.c: Likewise.
	* sysdeps/sh/nofpu/Implies: New file.
	* sysdeps/sh/s_fma.c: Remove file.
	* sysdeps/sh/s_fmaf.c: Likewise.
	* sysdeps/tile/Implies: Add ieee754/soft-fp.
	* sysdeps/tile/s_fma.c: Remove file.
	* sysdeps/tile/s_fmaf.c: Likewise.
2017-12-12 23:35:21 +00:00
Joseph Myers
775e99641e Use soft-fp fma for no-FPU ColdFire (bug 13304).
Systems without floating-point exceptions and rounding modes should
use the soft-fp versions of fmaf and fma, not the sysdeps/ieee754
versions that rely on setting rounding to zero and testing for the
"inexact" exception; this has been noted on
<https://sourceware.org/glibc/wiki/PortStatus> for some time.  This
patch makes no-FPU ColdFire use the soft-fp files; sfp-machine.h is
made to include the nios2 version of sfp-machine.h which seems
sufficiently generic for 32-bit systems.

	[BZ #13304]
	* sysdeps/m68k/coldfire/nofpu/s_fma.c: New file.
	* sysdeps/m68k/coldfire/nofpu/s_fmaf.c: Likewise.
	* sysdeps/m68k/coldfire/nofpu/sfp-machine.h: Likewise.
2015-09-25 17:30:56 +00:00