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authorJoseph Myers <joseph@codesourcery.com>2017-12-12 23:34:05 +0000
committerJoseph Myers <joseph@codesourcery.com>2017-12-12 23:35:21 +0000
commit6f7c009282a5f7129e359c9ba8556e7e3ac229ec (patch)
tree8e68cb241360b9cef4ffd94a8e2173df25a8b2b6 /sysdeps/ieee754/soft-fp
parentac817e083b37a5c25d05cde8bde302d7a93ffc5e (diff)
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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.
Diffstat (limited to 'sysdeps/ieee754/soft-fp')
-rw-r--r--sysdeps/ieee754/soft-fp/Makefile3
-rw-r--r--sysdeps/ieee754/soft-fp/s_fma.c68
-rw-r--r--sysdeps/ieee754/soft-fp/s_fmaf.c68
-rw-r--r--sysdeps/ieee754/soft-fp/s_fmal.c66
4 files changed, 205 insertions, 0 deletions
diff --git a/sysdeps/ieee754/soft-fp/Makefile b/sysdeps/ieee754/soft-fp/Makefile
new file mode 100644
index 0000000000..ada13e8b70
--- /dev/null
+++ b/sysdeps/ieee754/soft-fp/Makefile
@@ -0,0 +1,3 @@
+ifeq ($(subdir),math)
+CPPFLAGS += -I../soft-fp
+endif
diff --git a/sysdeps/ieee754/soft-fp/s_fma.c b/sysdeps/ieee754/soft-fp/s_fma.c
new file mode 100644
index 0000000000..313547d061
--- /dev/null
+++ b/sysdeps/ieee754/soft-fp/s_fma.c
@@ -0,0 +1,68 @@
+/* Implement fma using soft-fp.
+ Copyright (C) 2013-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ In addition to the permissions in the GNU Lesser General Public
+ License, the Free Software Foundation gives you unlimited
+ permission to link the compiled version of this file into
+ combinations with other programs, and to distribute those
+ combinations without any restriction coming from the use of this
+ file. (The Lesser General Public License restrictions do apply in
+ other respects; for example, they cover modification of the file,
+ and distribution when not linked into a combine executable.)
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include <libc-diag.h>
+#include <libm-alias-double.h>
+
+/* R_e is not set in cases where it is not used in packing, but the
+ compiler does not see that it is set in all cases where it is
+ used, resulting in warnings that it may be used uninitialized.
+ The location of the warning differs in different versions of GCC,
+ it may be where R is defined using a macro or it may be where the
+ macro is defined. */
+DIAG_PUSH_NEEDS_COMMENT;
+DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized");
+
+#include "soft-fp.h"
+#include "double.h"
+
+double
+__fma (double a, double b, double c)
+{
+ FP_DECL_EX;
+ FP_DECL_D (A);
+ FP_DECL_D (B);
+ FP_DECL_D (C);
+ FP_DECL_D (R);
+ double r;
+
+ FP_INIT_ROUNDMODE;
+ FP_UNPACK_D (A, a);
+ FP_UNPACK_D (B, b);
+ FP_UNPACK_D (C, c);
+ FP_FMA_D (R, A, B, C);
+ FP_PACK_D (r, R);
+ FP_HANDLE_EXCEPTIONS;
+
+ return r;
+}
+DIAG_POP_NEEDS_COMMENT;
+
+#ifndef __fma
+libm_alias_double (__fma, fma)
+#endif
diff --git a/sysdeps/ieee754/soft-fp/s_fmaf.c b/sysdeps/ieee754/soft-fp/s_fmaf.c
new file mode 100644
index 0000000000..295223da50
--- /dev/null
+++ b/sysdeps/ieee754/soft-fp/s_fmaf.c
@@ -0,0 +1,68 @@
+/* Implement fmaf using soft-fp.
+ Copyright (C) 2013-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ In addition to the permissions in the GNU Lesser General Public
+ License, the Free Software Foundation gives you unlimited
+ permission to link the compiled version of this file into
+ combinations with other programs, and to distribute those
+ combinations without any restriction coming from the use of this
+ file. (The Lesser General Public License restrictions do apply in
+ other respects; for example, they cover modification of the file,
+ and distribution when not linked into a combine executable.)
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include <libc-diag.h>
+#include <libm-alias-float.h>
+
+/* R_e is not set in cases where it is not used in packing, but the
+ compiler does not see that it is set in all cases where it is
+ used, resulting in warnings that it may be used uninitialized.
+ The location of the warning differs in different versions of GCC,
+ it may be where R is defined using a macro or it may be where the
+ macro is defined. */
+DIAG_PUSH_NEEDS_COMMENT;
+DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized");
+
+#include "soft-fp.h"
+#include "single.h"
+
+float
+__fmaf (float a, float b, float c)
+{
+ FP_DECL_EX;
+ FP_DECL_S (A);
+ FP_DECL_S (B);
+ FP_DECL_S (C);
+ FP_DECL_S (R);
+ float r;
+
+ FP_INIT_ROUNDMODE;
+ FP_UNPACK_S (A, a);
+ FP_UNPACK_S (B, b);
+ FP_UNPACK_S (C, c);
+ FP_FMA_S (R, A, B, C);
+ FP_PACK_S (r, R);
+ FP_HANDLE_EXCEPTIONS;
+
+ return r;
+}
+DIAG_POP_NEEDS_COMMENT;
+
+#ifndef __fmaf
+libm_alias_float (__fma, fma)
+#endif
diff --git a/sysdeps/ieee754/soft-fp/s_fmal.c b/sysdeps/ieee754/soft-fp/s_fmal.c
new file mode 100644
index 0000000000..79be52c4f1
--- /dev/null
+++ b/sysdeps/ieee754/soft-fp/s_fmal.c
@@ -0,0 +1,66 @@
+/* Implement fmal using soft-fp.
+ Copyright (C) 2013-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ In addition to the permissions in the GNU Lesser General Public
+ License, the Free Software Foundation gives you unlimited
+ permission to link the compiled version of this file into
+ combinations with other programs, and to distribute those
+ combinations without any restriction coming from the use of this
+ file. (The Lesser General Public License restrictions do apply in
+ other respects; for example, they cover modification of the file,
+ and distribution when not linked into a combine executable.)
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <math.h>
+#include <libc-diag.h>
+#include <libm-alias-ldouble.h>
+
+/* R_e is not set in cases where it is not used in packing, but the
+ compiler does not see that it is set in all cases where it is
+ used, resulting in warnings that it may be used uninitialized.
+ The location of the warning differs in different versions of GCC,
+ it may be where R is defined using a macro or it may be where the
+ macro is defined. */
+DIAG_PUSH_NEEDS_COMMENT;
+DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized");
+
+#include "soft-fp.h"
+#include "quad.h"
+
+long double
+__fmal (long double a, long double b, long double c)
+{
+ FP_DECL_EX;
+ FP_DECL_Q (A);
+ FP_DECL_Q (B);
+ FP_DECL_Q (C);
+ FP_DECL_Q (R);
+ long double r;
+
+ FP_INIT_ROUNDMODE;
+ FP_UNPACK_Q (A, a);
+ FP_UNPACK_Q (B, b);
+ FP_UNPACK_Q (C, c);
+ FP_FMA_Q (R, A, B, C);
+ FP_PACK_Q (r, R);
+ FP_HANDLE_EXCEPTIONS;
+
+ return r;
+}
+DIAG_POP_NEEDS_COMMENT;
+
+libm_alias_ldouble (__fma, fma)