arm: Fix fenv support

The previous fenv support for ARM used the soft-float implementation of
FreeBSD.  Newlib uses the one from libgcc by default.  They are not
compatible.  Having an GCC incompatible soft-float fenv support in
Newlib makes no sense.  A long-term solution could be to provide a
libgcc compatible soft-float support.  This likely requires changes in
the GCC configuration.  For now, provide a stub implementation for
soft-float multilibs similar to RISC-V.

Move implementation to one file and delete now unused files.  Hide
implementation details.  Remove function parameter names from header
file to avoid name conflicts.

Provide VFP support if __SOFTFP__ is not defined like glibc.

Reviewed-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
Signed-off-by: Eshan dhawan <eshandhawan51@gmail.com>

5 files changed, 110 insertions, 296 deletions

diff --git a/newlib/libm/machine/arm/Makefile.am b/newlib/libm/machine/arm/Makefile.am
index a64ee59..180a37f 100644
--- a/newlib/libm/machine/arm/Makefile.am
+++ b/newlib/libm/machine/arm/Makefile.am
@@ -32,9 +32,7 @@ LIB_SOURCES = \
 	fesetexceptflag.c \
 	fesetround.c \
 	fetestexcept.c \
-	feupdateenv.c \
-	fenv-vfp.c \
-	fenv-softfp.c 
+	feupdateenv.c
 
 
 noinst_LIBRARIES = lib.a
diff --git a/newlib/libm/machine/arm/Makefile.in b/newlib/libm/machine/arm/Makefile.in
index ecfa684..aa23dd4 100644
--- a/newlib/libm/machine/arm/Makefile.in
+++ b/newlib/libm/machine/arm/Makefile.in
@@ -83,8 +83,7 @@ am__objects_1 = lib_a-e_sqrt.$(OBJEXT) lib_a-ef_sqrt.$(OBJEXT) \
 	lib_a-fenv.$(OBJEXT) lib_a-feraiseexcept.$(OBJEXT) \
 	lib_a-fesetenv.$(OBJEXT) lib_a-fesetexceptflag.$(OBJEXT) \
 	lib_a-fesetround.$(OBJEXT) lib_a-fetestexcept.$(OBJEXT) \
-	lib_a-feupdateenv.$(OBJEXT) lib_a-fenv-vfp.$(OBJEXT) \
-	lib_a-fenv-softfp.$(OBJEXT)
+	lib_a-feupdateenv.$(OBJEXT)
 am_lib_a_OBJECTS = $(am__objects_1)
 lib_a_OBJECTS = $(am_lib_a_OBJECTS)
 DEFAULT_INCLUDES = -I.@am__isrc@
@@ -237,9 +236,7 @@ LIB_SOURCES = \
 	fesetexceptflag.c \
 	fesetround.c \
 	fetestexcept.c \
-	feupdateenv.c \
-	fenv-vfp.c \
-	fenv-softfp.c 
+	feupdateenv.c
 
 noinst_LIBRARIES = lib.a
 lib_a_SOURCES = $(LIB_SOURCES)
@@ -479,18 +476,6 @@ lib_a-feupdateenv.o: feupdateenv.c
 lib_a-feupdateenv.obj: feupdateenv.c
 	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-feupdateenv.obj `if test -f 'feupdateenv.c'; then $(CYGPATH_W) 'feupdateenv.c'; else $(CYGPATH_W) '$(srcdir)/feupdateenv.c'; fi`
 
-lib_a-fenv-vfp.o: fenv-vfp.c
-	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-fenv-vfp.o `test -f 'fenv-vfp.c' || echo '$(srcdir)/'`fenv-vfp.c
-
-lib_a-fenv-vfp.obj: fenv-vfp.c
-	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-fenv-vfp.obj `if test -f 'fenv-vfp.c'; then $(CYGPATH_W) 'fenv-vfp.c'; else $(CYGPATH_W) '$(srcdir)/fenv-vfp.c'; fi`
-
-lib_a-fenv-softfp.o: fenv-softfp.c
-	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-fenv-softfp.o `test -f 'fenv-softfp.c' || echo '$(srcdir)/'`fenv-softfp.c
-
-lib_a-fenv-softfp.obj: fenv-softfp.c
-	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-fenv-softfp.obj `if test -f 'fenv-softfp.c'; then $(CYGPATH_W) 'fenv-softfp.c'; else $(CYGPATH_W) '$(srcdir)/fenv-softfp.c'; fi`
-
 ID: $(HEADERS) $(SOURCES) $(LISP) $(TAGS_FILES)
 	list='$(SOURCES) $(HEADERS) $(LISP) $(TAGS_FILES)'; \
 	unique=`for i in $$list; do \
diff --git a/newlib/libm/machine/arm/fenv-softfp.c b/newlib/libm/machine/arm/fenv-softfp.c
deleted file mode 100644
index a576cc1..0000000
--- a/newlib/libm/machine/arm/fenv-softfp.c
+++ /dev/null
@@ -1,32 +0,0 @@
-/*-
- * Copyright (c) 2013 Andrew Turner <andrew@FreeBSD.ORG>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * $FreeBSD$
- */
-
-#define	FENV_MANGLE(x)	__softfp_ ##x
-#include <machine/fenv-mangle.h>
-#include "fenv.c"
-
diff --git a/newlib/libm/machine/arm/fenv-vfp.c b/newlib/libm/machine/arm/fenv-vfp.c
deleted file mode 100644
index 297e812..0000000
--- a/newlib/libm/machine/arm/fenv-vfp.c
+++ /dev/null
@@ -1,32 +0,0 @@
-/*-
- * Copyright (c) 2013 Andrew Turner <andrew@FreeBSD.ORG>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * $FreeBSD$
- */
-
-#define	FENV_MANGLE(x)	__vfp_ ##x
-#include <machine/fenv-mangle.h>
-#include "fenv.c"
-
diff --git a/newlib/libm/machine/arm/fenv.c b/newlib/libm/machine/arm/fenv.c
index 5b61ab8..0735cd1 100644
--- a/newlib/libm/machine/arm/fenv.c
+++ b/newlib/libm/machine/arm/fenv.c
@@ -1,7 +1,7 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
  *
- * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
+ * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
  * Copyright (c) 2013 Andrew Turner <andrew@FreeBSD.ORG>
  * All rights reserved.
  *
@@ -29,300 +29,195 @@
  * $FreeBSD$
  */
 
-#define	__fenv_static
 #include <fenv.h>
 
-#include <machine/acle-compat.h>
-
-#if __ARM_ARCH >= 6
-#define FENV_ARMv6
-#endif
-
-/* When SOFTFP_ABI is defined we are using the softfp ABI. */
-#if defined(__VFP_FP__) && !defined(__ARM_PCS_VFP)
-#define SOFTFP_ABI
+#ifndef __SOFTFP__
+#define	vmrs_fpscr(__r)	__asm __volatile("vmrs %0, fpscr" : "=&r"(__r))
+#define	vmsr_fpscr(__r)	__asm __volatile("vmsr fpscr, %0" : : "r"(__r))
+#define	_FPU_MASK_SHIFT	8
+#define	_ROUND_MASK	(FE_TONEAREST | FE_DOWNWARD | \
+			 FE_UPWARD | FE_TOWARDZERO)
 #endif
 
-
-#ifndef FENV_MANGLE
-/*
- * Hopefully the system ID byte is immutable, so it's valid to use
- * this as a default environment.
- */
 fenv_t __fe_dfl_env = { 0 };
 
 const fenv_t *_fe_dfl_env = &__fe_dfl_env;
-#endif
-
-
-/* If this is a non-mangled softfp version special processing is required */
-#if defined(FENV_MANGLE) || !defined(SOFTFP_ABI) || !defined(FENV_ARMv6)
-
-/*
- * The following macros map between the softfloat emulator's flags and
- * the hardware's FPSR.  The hardware this file was written for doesn't
- * have rounding control bits, so we stick those in the system ID byte.
- */
-#ifndef __ARM_PCS_VFP
-#define	__set_env(env, flags, mask, rnd) env = ((flags)			\
-						| (mask)<<_FPUSW_SHIFT	\
-						| (rnd) << 24)
-#define	__env_flags(env)		((env) & FE_ALL_EXCEPT)
-#define	__env_mask(env)			(((env) >> _FPUSW_SHIFT)	\
-						& FE_ALL_EXCEPT)
-#define	__env_round(env)		(((env) >> 24) & _ROUND_MASK)
-
-#include <machine/fenv-softfloat.h>
-
-#else /* __ARM_PCS_VFP PRESENT */
-
-#include <machine/fenv-vfp.h>
-
-#endif /* __ARM_PCS_VFP */
-
-#ifdef __GNUC_GNU_INLINE__
-#error "This file must be compiled with C99 'inline' semantics"
-#endif
-
-extern inline int feclearexcept(int excepts);
-extern inline int fegetexceptflag(fexcept_t *flagp, int excepts);
-extern inline int fesetexceptflag(const fexcept_t *flagp, int excepts);
-extern inline int feraiseexcept(int excepts);
-extern inline int fetestexcept(int excepts);
-extern inline int fegetround(void);
-extern inline int fesetround(int round);
-extern inline int fegetenv(fenv_t *envp);
-extern inline int feholdexcept(fenv_t *envp);
-extern inline int fesetenv(const fenv_t *envp);
-extern inline int feupdateenv(const fenv_t *envp);
-extern inline int feenableexcept(int __mask);
-extern inline int fedisableexcept(int __mask);
-extern inline int fegetexcept(void);
-
-#else /* !FENV_MANGLE && SOFTFP_ABI */
-/* Set by libc when the VFP unit is enabled */
-
-int _libc_arm_fpu_present;
-
-int __softfp_feclearexcept(int excepts);
-int __softfp_fegetexceptflag(fexcept_t *flagp, int excepts);
-int __softfp_fesetexceptflag(const fexcept_t *flagp, int excepts);
-int __softfp_feraiseexcept(int excepts);
-int __softfp_fetestexcept(int excepts);
-int __softfp_fegetround(void);
-int __softfp_fesetround(int round);
-int __softfp_fegetenv(fenv_t *envp);
-int __softfp_feholdexcept(fenv_t *envp);
-int __softfp_fesetenv(const fenv_t *envp);
-int __softfp_feupdateenv(const fenv_t *envp);
-int __softfp_feenableexcept(int __mask);
-int __softfp_fedisableexcept(int __mask);
-int __softfp_fegetexcept(void);
-
-int __vfp_feclearexcept(int excepts);
-int __vfp_fegetexceptflag(fexcept_t *flagp, int excepts);
-int __vfp_fesetexceptflag(const fexcept_t *flagp, int excepts);
-int __vfp_feraiseexcept(int excepts);
-int __vfp_fetestexcept(int excepts);
-int __vfp_fegetround(void);
-int __vfp_fesetround(int round);
-int __vfp_fegetenv(fenv_t *envp);
-int __vfp_feholdexcept(fenv_t *envp);
-int __vfp_fesetenv(const fenv_t *envp);
-int __vfp_feupdateenv(const fenv_t *envp);
-int __vfp_feenableexcept(int __mask);
-int __vfp_fedisableexcept(int __mask);
-int __vfp_fegetexcept(void);
-
-static int
-__softfp_round_to_vfp(int round)
-{
-
-	switch (round) {
-	case FE_TONEAREST:
-	default:
-		return VFP_FE_TONEAREST;
-	case FE_TOWARDZERO:
-		return VFP_FE_TOWARDZERO;
-	case FE_UPWARD:
-		return VFP_FE_UPWARD;
-	case FE_DOWNWARD:
-		return VFP_FE_DOWNWARD;
-	}
-}
-
-static int
-__softfp_round_from_vfp(int round)
-{
-
-	switch (round) {
-	case VFP_FE_TONEAREST:
-	default:
-		return FE_TONEAREST;
-	case VFP_FE_TOWARDZERO:
-		return FE_TOWARDZERO;
-	case VFP_FE_UPWARD:
-		return FE_UPWARD;
-	case VFP_FE_DOWNWARD:
-		return FE_DOWNWARD;
-	}
-}
 
 int feclearexcept(int excepts)
 {
+#ifndef __SOFTFP__
+	fexcept_t __fpsr;
 
-	if (_libc_arm_fpu_present)
-		__vfp_feclearexcept(excepts);
-	__softfp_feclearexcept(excepts);
-
+	vmrs_fpscr(__fpsr);
+	__fpsr &= ~excepts;
+	vmsr_fpscr(__fpsr);
+#endif
 	return (0);
 }
 
 int fegetexceptflag(fexcept_t *flagp, int excepts)
 {
-	fexcept_t __vfp_flagp;
-
-	__vfp_flagp = 0;
-	if (_libc_arm_fpu_present)
-		__vfp_fegetexceptflag(&__vfp_flagp, excepts);
-	__softfp_fegetexceptflag(flagp, excepts);
-
-	*flagp |= __vfp_flagp;
+#ifndef __SOFTFP__
+	fexcept_t __fpsr;
 
+	vmrs_fpscr(__fpsr);
+	__fpsr &= ~excepts;
+	__fpsr |= *flagp & excepts;
+	vmsr_fpscr(__fpsr);
+#endif
 	return (0);
 }
 
 int fesetexceptflag(const fexcept_t *flagp, int excepts)
 {
+#ifndef __SOFTFP__
+	fexcept_t __fpsr;
 
-	if (_libc_arm_fpu_present)
-		__vfp_fesetexceptflag(flagp, excepts);
-	__softfp_fesetexceptflag(flagp, excepts);
-
+	vmrs_fpscr(__fpsr);
+	__fpsr &= ~excepts;
+	__fpsr |= *flagp & excepts;
+	vmsr_fpscr(__fpsr);
+#endif
 	return (0);
 }
 
 int feraiseexcept(int excepts)
 {
+#ifndef __SOFTFP__
+	fexcept_t __ex = excepts;
 
-	if (_libc_arm_fpu_present)
-		__vfp_feraiseexcept(excepts);
-	__softfp_feraiseexcept(excepts);
-
+	fesetexceptflag(&__ex, excepts);
+#endif
 	return (0);
 }
 
 int fetestexcept(int excepts)
 {
-	int __got_excepts;
+#ifndef __SOFTFP__
+	fexcept_t __fpsr;
 
-	__got_excepts = 0;
-	if (_libc_arm_fpu_present)
-		__got_excepts = __vfp_fetestexcept(excepts);
-	__got_excepts |= __softfp_fetestexcept(excepts);
-
-	return (__got_excepts);
+	vmrs_fpscr(__fpsr);
+	return (__fpsr & excepts);
+#else
+	return (0);
+#endif
 }
 
 int fegetround(void)
 {
+#ifndef __SOFTFP__
+	fenv_t __fpsr;
 
-	if (_libc_arm_fpu_present)
-		return __softfp_round_from_vfp(__vfp_fegetround());
-	return __softfp_fegetround();
+	vmrs_fpscr(__fpsr);
+	return (__fpsr & _ROUND_MASK);
+#else
+#ifdef FE_TONEAREST
+	return (FE_TONEAREST);
+#else
+	return (0);
+#endif
+#endif
 }
 
 int fesetround(int round)
 {
+#ifndef __SOFTFP__
+	fenv_t __fpsr;
 
-	if (_libc_arm_fpu_present)
-		__vfp_fesetround(__softfp_round_to_vfp(round));
-	__softfp_fesetround(round);
-
+	vmrs_fpscr(__fpsr);
+	__fpsr &= ~(_ROUND_MASK);
+	__fpsr |= round;
+	vmsr_fpscr(__fpsr);
+#endif
 	return (0);
 }
 
 int fegetenv(fenv_t *envp)
 {
-	fenv_t __vfp_envp;
-
-	__vfp_envp = 0;
-	if (_libc_arm_fpu_present)
-		__vfp_fegetenv(&__vfp_envp);
-	__softfp_fegetenv(envp);
-	*envp |= __vfp_envp;
 
+#ifndef __SOFTFP__
+	vmrs_fpscr(*envp);
+#endif
 	return (0);
 }
 
 int feholdexcept(fenv_t *envp)
 {
-	fenv_t __vfp_envp;
-
-	__vfp_envp = 0;
-	if (_libc_arm_fpu_present)
-		__vfp_feholdexcept(&__vfp_envp);
-	__softfp_feholdexcept(envp);
-	*envp |= __vfp_envp;
+#ifndef __SOFTFP__
+	fenv_t __env;
 
+	vmrs_fpscr(__env);
+	*envp = __env;
+	__env &= ~(FE_ALL_EXCEPT);
+	vmsr_fpscr(__env);
+#endif
 	return (0);
 }
 
 int fesetenv(const fenv_t *envp)
 {
 
-	if (_libc_arm_fpu_present)
-		__vfp_fesetenv(envp);
-	__softfp_fesetenv(envp);
-
+#ifndef __SOFTFP__
+	vmsr_fpscr(*envp);
+#endif
 	return (0);
 }
 
 int feupdateenv(const fenv_t *envp)
 {
+#ifndef __SOFTFP__
+	fexcept_t __fpsr;
 
-	if (_libc_arm_fpu_present)
-		__vfp_feupdateenv(envp);
-	__softfp_feupdateenv(envp);
-
+	vmrs_fpscr(__fpsr);
+	vmsr_fpscr(*envp);
+	feraiseexcept(__fpsr & FE_ALL_EXCEPT);
+#else
+#if defined(FE_NOMASK_ENV) && FE_ALL_EXCEPT != 0
+	if (envp == FE_NOMASK_ENV)
+		return (1);
+#endif
+#endif
 	return (0);
 }
 
 int feenableexcept(int __mask)
 {
-	int __unmasked;
-
-	__unmasked = 0;
-	if (_libc_arm_fpu_present)
-		__unmasked = __vfp_feenableexcept(__mask);
-	__unmasked |= __softfp_feenableexcept(__mask);
+#ifndef __SOFTFP__
+	fenv_t __old_fpsr, __new_fpsr;
 
-	return (__unmasked);
+	vmrs_fpscr(__old_fpsr);
+	__new_fpsr = __old_fpsr |
+	    ((__mask & FE_ALL_EXCEPT) << _FPU_MASK_SHIFT);
+	vmsr_fpscr(__new_fpsr);
+	return ((__old_fpsr >> _FPU_MASK_SHIFT) & FE_ALL_EXCEPT);
+#else
+	return (0);
+#endif
 }
 
 int fedisableexcept(int __mask)
 {
-	int __unmasked;
+#ifndef __SOFTFP__
+	fenv_t __old_fpsr, __new_fpsr;
 
-	__unmasked = 0;
-	if (_libc_arm_fpu_present)
-		__unmasked = __vfp_fedisableexcept(__mask);
-	__unmasked |= __softfp_fedisableexcept(__mask);
-
-	return (__unmasked);
+	vmrs_fpscr(__old_fpsr);
+	__new_fpsr = __old_fpsr &
+	    ~((__mask & FE_ALL_EXCEPT) << _FPU_MASK_SHIFT);
+	vmsr_fpscr(__new_fpsr);
+	return ((__old_fpsr >> _FPU_MASK_SHIFT) & FE_ALL_EXCEPT);
+#else
+	return (0);
+#endif
 }
 
 int fegetexcept(void)
 {
-	int __unmasked;
-
-	__unmasked = 0;
-	if (_libc_arm_fpu_present)
-		__unmasked = __vfp_fegetexcept();
-	__unmasked |= __softfp_fegetexcept();
-
-	return (__unmasked);
-}
+#ifndef __SOFTFP__
+	fenv_t __fpsr;
 
+	vmrs_fpscr(__fpsr);
+	return (__fpsr & FE_ALL_EXCEPT);
+#else
+	return (0);
 #endif
-
+}