[newlib-cygwin] fenv: move shared x86 fenv.c to libm/machine/shared_x86

[newlib-cygwin] fenv: move shared x86 fenv.c to libm/machine/shared_x86

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=642be00cdb5819b41bad4045de5fae395fffc2f5

commit 642be00cdb5819b41bad4045de5fae395fffc2f5
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Wed Mar 24 10:51:20 2021 +0100

    fenv: move shared x86 fenv.c to libm/machine/shared_x86
    
    Include this file from both sharing architectures, i386 and x86_64.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 newlib/libm/machine/i386/fenv.c       |   2 +-
 newlib/libm/machine/shared_x86/fenv.c | 477 ++++++++++++++++++++++++++++++++++
 newlib/libm/machine/x86_64/fenv.c     | 474 +--------------------------------
 3 files changed, 480 insertions(+), 473 deletions(-)

diff --git a/newlib/libm/machine/i386/fenv.c b/newlib/libm/machine/i386/fenv.c
index 1a97f5617..4679f03e1 100644
--- a/newlib/libm/machine/i386/fenv.c
+++ b/newlib/libm/machine/i386/fenv.c
@@ -4,4 +4,4 @@
  * (c) Copyright 2019 Joel Sherrill <joel@rtems.org>
  */
 
-#include "../x86_64/fenv.c"
+#include "../shared_x86/fenv.c"
diff --git a/newlib/libm/machine/shared_x86/fenv.c b/newlib/libm/machine/shared_x86/fenv.c
new file mode 100644
index 000000000..ccc08e2d8
--- /dev/null
+++ b/newlib/libm/machine/shared_x86/fenv.c
@@ -0,0 +1,477 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2010-2019 Red Hat, Inc.
+ */
+
+#define _GNU_SOURCE        // for FE_NOMASK_ENV
+
+#include <fenv.h>
+#include <errno.h>
+#include <string.h>        // for memcpy 
+#include <stdbool.h>
+
+/*  x87 supports subnormal numbers so we need it below. */
+#define __FE_DENORM	(1 << 1)
+/* mask (= 0x3f) to disable all exceptions at initialization */
+#define __FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM)
+
+/*  Mask and shift amount for rounding bits.  */
+#define FE_CW_ROUND_MASK	(0x0c00)
+#define FE_CW_ROUND_SHIFT	(10)
+/*  Same, for SSE MXCSR.  */
+#define FE_MXCSR_ROUND_MASK	(0x6000)
+#define FE_MXCSR_ROUND_SHIFT	(13)
+
+/*  Mask and shift amount for precision bits.  */
+#define FE_CW_PREC_MASK		(0x0300)
+#define FE_CW_PREC_SHIFT	(8)
+
+/*  In x87, exception status bits and mask bits occupy
+   corresponding bit positions in the status and control
+   registers, respectively.  In SSE, they are both located
+   in the control-and-status register, with the status bits
+   corresponding to the x87 positions, and the mask bits
+   shifted by this amount to the left.  */
+#define FE_SSE_EXCEPT_MASK_SHIFT (7)
+
+/* These are writable so we can initialise them at startup.  */
+static fenv_t fe_nomask_env;
+
+/* These pointers provide the outside world with read-only access to them.  */
+const fenv_t *_fe_nomask_env = &fe_nomask_env;
+
+/* Assume i686 or above (hence SSE available) these days, with the
+   compiler feels free to use it (depending on compile- time flags of
+   course), but we should avoid needlessly breaking any purely integer mode
+   apps (or apps compiled with -mno-sse), so we only manage SSE state in this
+   fenv module if we detect that SSE instructions are available at runtime.
+   If we didn't do this, all applications run on older machines would bomb
+   out with an invalid instruction exception right at startup; let's not
+   be *that* WJM!  */
+static inline bool use_sse(void)
+{
+  unsigned int edx, eax;
+
+  /* Check for presence of SSE: invoke CPUID #1, check EDX bit 25.  */
+  eax = 1;
+  __asm__ volatile ("cpuid" : "=d" (edx), "+a" (eax) :: "%ecx", "%ebx");
+  /* If this flag isn't set we'll avoid trying to execute any SSE.  */
+  if ((edx & (1 << 25)) != 0)
+    return true;
+
+  return false;
+}
+
+/* forward declaration */
+static void _feinitialise (void);
+
+/*  This function enables traps for each of the exceptions as indicated
+   by the parameter except. The individual exceptions are described in
+   [ ... glibc manual xref elided ...]. Only the specified exceptions are
+   enabled, the status of the other exceptions is not changed.
+    The function returns the previous enabled exceptions in case the
+   operation was successful, -1 otherwise.  */
+int
+feenableexcept (int excepts)
+{
+  unsigned short cw, old_cw;
+  unsigned int mxcsr = 0;
+
+  if (excepts & ~FE_ALL_EXCEPT)
+    return -1;
+
+  /* Get control words.  */
+  __asm__ volatile ("fnstcw %0" : "=m" (old_cw) : );
+  if (use_sse())
+    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
+
+  /* Enable exceptions by clearing mask bits.  */
+  cw = old_cw & ~excepts;
+  mxcsr &= ~(excepts << FE_SSE_EXCEPT_MASK_SHIFT);
+
+  /* Store updated control words.  */
+  __asm__ volatile ("fldcw %0" :: "m" (cw));
+  if (use_sse())
+    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
+
+  /* Return old value.  We assume SSE and x87 stay in sync.  Note that
+     we are returning a mask of enabled exceptions, which is the opposite
+     of the flags in the register, which are set to disable (mask) their
+     related exceptions.  */
+  return (~old_cw) & FE_ALL_EXCEPT;
+}
+
+/*  This function disables traps for each of the exceptions as indicated
+   by the parameter except. The individual exceptions are described in
+   [ ... glibc manual xref elided ...]. Only the specified exceptions are
+   disabled, the status of the other exceptions is not changed.
+    The function returns the previous enabled exceptions in case the
+   operation was successful, -1 otherwise.  */
+int
+fedisableexcept (int excepts)
+{
+  unsigned short cw, old_cw;
+  unsigned int mxcsr = 0;
+
+  if (excepts & ~FE_ALL_EXCEPT)
+    return -1;
+
+  /* Get control words.  */
+  __asm__ volatile ("fnstcw %0" : "=m" (old_cw) : );
+  if (use_sse())
+    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
+
+  /* Disable exceptions by setting mask bits.  */
+  cw = old_cw | excepts;
+  mxcsr |= (excepts << FE_SSE_EXCEPT_MASK_SHIFT);
+
+  /* Store updated control words.  */
+  __asm__ volatile ("fldcw %0" :: "m" (cw));
+  if (use_sse())
+    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
+
+  /* Return old value.  We assume SSE and x87 stay in sync.  Note that
+     we are returning a mask of enabled exceptions, which is the opposite
+     of the flags in the register, which are set to disable (mask) their
+     related exceptions.  */
+  return (~old_cw) & FE_ALL_EXCEPT;
+}
+
+/*  This function returns a bitmask of all currently enabled exceptions. It
+   returns -1 in case of failure.  */
+int
+fegetexcept (void)
+{
+  unsigned short cw;
+
+  /* Get control word.  We assume SSE and x87 stay in sync.  */
+  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
+
+  /* Exception is *dis*abled when mask bit is set.  */
+  return (~cw) & FE_ALL_EXCEPT;
+}
+
+/*  Store the floating-point environment in the variable pointed to by envp.
+   The function returns zero in case the operation was successful, a non-zero
+   value otherwise.  */
+int
+fegetenv (fenv_t *envp)
+{
+  /* fnstenv disables all exceptions in the x87 FPU; as this is not what is
+     desired here, reload the cfg saved from the x87 FPU, back to the FPU */
+  __asm__ volatile ("fnstenv %0\n\
+                     fldenv %0"
+		    : "=m" (envp->_fpu) : );
+  if (use_sse())
+    __asm__ volatile ("stmxcsr %0" : "=m" (envp->_sse_mxcsr) : );
+  return 0;
+}
+
+/*  Store the current floating-point environment in the object pointed to
+   by envp. Then clear all exception flags, and set the FPU to trap no
+   exceptions.  Not all FPUs support trapping no exceptions; if feholdexcept
+   cannot set this mode, it returns nonzero value.  If it succeeds, it
+   returns zero.  */
+int
+feholdexcept (fenv_t *envp)
+{
+  unsigned int mxcsr;
+  fegetenv (envp);
+  mxcsr = envp->_sse_mxcsr & ~FE_ALL_EXCEPT;
+  if (use_sse())
+    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
+  __asm__ volatile ("fnclex");
+  fedisableexcept (FE_ALL_EXCEPT);
+  return 0;
+}
+
+/*  Set the floating-point environment to that described by envp.  The
+   function returns zero in case the operation was successful, a non-zero
+   value otherwise.  */
+int
+fesetenv (const fenv_t *envp)
+{
+   if ((envp == FE_DFL_ENV || envp == FE_NOMASK_ENV) &&
+       envp->_fpu._fpu_cw == 0)
+     _feinitialise ();
+
+  __asm__ volatile ("fldenv %0" :: "m" (envp->_fpu) );
+  if (use_sse())
+    __asm__ volatile ("ldmxcsr %0" :: "m" (envp->_sse_mxcsr));
+  return 0;
+}
+
+/*  Like fesetenv, this function sets the floating-point environment to
+   that described by envp. However, if any exceptions were flagged in the
+   status word before feupdateenv was called, they remain flagged after
+   the call.  In other words, after feupdateenv is called, the status
+   word is the bitwise OR of the previous status word and the one saved
+   in envp.  The function returns zero in case the operation was successful,
+   a non-zero value otherwise.  */
+int
+feupdateenv (const fenv_t *envp)
+{
+  fenv_t envcopy;
+  unsigned int mxcsr = 0;
+  unsigned short sw;
+
+  /* Don't want to modify *envp, but want to update environment atomically,
+     so take a copy and merge the existing exceptions into it.  */
+  memcpy (&envcopy, envp, sizeof *envp);
+  __asm__ volatile ("fnstsw %0" : "=m" (sw) : );
+  if (use_sse())
+    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
+  envcopy._fpu._fpu_sw |= (sw & FE_ALL_EXCEPT);
+  envcopy._sse_mxcsr |= (mxcsr & FE_ALL_EXCEPT);
+
+  return fesetenv (&envcopy);
+}
+
+/*  This function clears all of the supported exception flags indicated by
+   excepts.  The function returns zero in case the operation was successful,
+   a non-zero value otherwise.  */
+int
+feclearexcept (int excepts)
+{
+  fenv_t fenv;
+
+  if (excepts & ~FE_ALL_EXCEPT)
+    return EINVAL;
+
+  /* Need to save/restore whole environment to modify status word.  */
+  fegetenv (&fenv);
+
+  /* Mask undesired bits out.  */
+  fenv._fpu._fpu_sw &= ~excepts;
+  fenv._sse_mxcsr &= ~excepts;
+
+  /* Set back into FPU state.  */
+  return fesetenv (&fenv);
+}
+
+/*  This function raises the supported exceptions indicated by
+   excepts.  If more than one exception bit in excepts is set the order
+   in which the exceptions are raised is undefined except that overflow
+   (FE_OVERFLOW) or underflow (FE_UNDERFLOW) are raised before inexact
+   (FE_INEXACT). Whether for overflow or underflow the inexact exception
+   is also raised is also implementation dependent.  The function returns
+   zero in case the operation was successful, a non-zero value otherwise.  */
+int
+feraiseexcept (int excepts)
+{
+  fenv_t fenv;
+
+  if (excepts & ~FE_ALL_EXCEPT)
+    return EINVAL;
+
+  /* Need to save/restore whole environment to modify status word.  */
+  __asm__ volatile ("fnstenv %0" : "=m" (fenv) : );
+
+  /* Set desired exception bits.  */
+  fenv._fpu._fpu_sw |= excepts;
+
+  /* Set back into FPU state.  */
+  __asm__ volatile ("fldenv %0" :: "m" (fenv));
+
+  /* And trigger them - whichever are unmasked.  */
+  __asm__ volatile ("fwait");
+
+  return 0;
+}
+
+/*  Test whether the exception flags indicated by the parameter except
+   are currently set. If any of them are, a nonzero value is returned
+   which specifies which exceptions are set. Otherwise the result is zero.  */
+int
+fetestexcept (int excepts)
+{
+  unsigned short sw;
+  unsigned int mxcsr = 0;
+
+  if (excepts & ~FE_ALL_EXCEPT)
+    return EINVAL;
+
+  /* Get status registers.  */
+  __asm__ volatile ("fnstsw %0" : "=m" (sw) : );
+  if (use_sse())
+    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
+
+  /* Mask undesired bits out and return result.  */
+  return (sw | mxcsr) & excepts;
+}
+/*  This function stores in the variable pointed to by flagp an
+   implementation-defined value representing the current setting of the
+   exception flags indicated by excepts.  The function returns zero in
+   case the operation was successful, a non-zero value otherwise.  */
+int
+fegetexceptflag (fexcept_t *flagp, int excepts)
+{
+  unsigned short sw;
+  unsigned int mxcsr = 0;
+
+  if (excepts & ~FE_ALL_EXCEPT)
+    return EINVAL;
+
+  /* Get status registers.  */
+  __asm__ volatile ("fnstsw %0" : "=m" (sw) : );
+  if (use_sse())
+    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
+
+  /* Mask undesired bits out and set result.  */
+  *flagp = (sw | mxcsr) & excepts;
+
+  return 0;
+}
+
+/*  This function restores the flags for the exceptions indicated by
+   excepts to the values stored in the variable pointed to by flagp.  */
+int
+fesetexceptflag (const fexcept_t *flagp, int excepts)
+{
+  fenv_t fenv;
+
+  if (excepts & ~FE_ALL_EXCEPT)
+    return EINVAL;
+
+  /* Need to save/restore whole environment to modify status word.  */
+  fegetenv (&fenv);
+
+  /* Set/Clear desired exception bits.  */
+  fenv._fpu._fpu_sw &= ~excepts;
+  fenv._fpu._fpu_sw |= excepts & *flagp;
+  fenv._sse_mxcsr &= ~excepts;
+  fenv._sse_mxcsr |= excepts & *flagp;
+
+  /* Set back into FPU state.  */
+  return fesetenv (&fenv);
+}
+
+/*  Returns the currently selected rounding mode, represented by one of the
+   values of the defined rounding mode macros.  */
+int
+fegetround (void)
+{
+  unsigned short cw;
+
+  /* Get control word.  We assume SSE and x87 stay in sync.  */
+  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
+
+  return (cw & FE_CW_ROUND_MASK) >> FE_CW_ROUND_SHIFT;
+}
+
+/*  Changes the currently selected rounding mode to round. If round does
+   not correspond to one of the supported rounding modes nothing is changed.
+   fesetround returns zero if it changed the rounding mode, a nonzero value
+   if the mode is not supported.  */
+int
+fesetround (int round)
+{
+  unsigned short cw;
+  unsigned int mxcsr = 0;
+
+  /* Will succeed for any valid value of the input parameter.  */
+  if (round < FE_TONEAREST || round > FE_TOWARDZERO)
+    return EINVAL;
+
+  /* Get control words.  */
+  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
+  if (use_sse())
+    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
+
+  /* Twiddle bits.  */
+  cw &= ~FE_CW_ROUND_MASK;
+  cw |= (round << FE_CW_ROUND_SHIFT);
+  mxcsr &= ~FE_MXCSR_ROUND_MASK;
+  mxcsr |= (round << FE_MXCSR_ROUND_SHIFT);
+
+  /* Set back into FPU state.  */
+  __asm__ volatile ("fldcw %0" :: "m" (cw));
+  if (use_sse())
+    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
+
+  /* Indicate success.  */
+  return 0;
+}
+
+#if defined(__CYGWIN__)
+/*  Returns the currently selected precision, represented by one of the
+   values of the defined precision macros.  */
+int
+fegetprec (void)
+{
+  unsigned short cw;
+
+  /* Get control word.  */
+  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
+
+  return (cw & FE_CW_PREC_MASK) >> FE_CW_PREC_SHIFT;
+}
+
+/* http://www.open-std.org/jtc1/sc22//WG14/www/docs/n752.htm:
+
+   The fesetprec function establishes the precision represented by its
+   argument prec.  If the argument does not match a precision macro, the
+   precision is not changed.
+
+   The fesetprec function returns a nonzero value if and only if the
+   argument matches a precision macro (that is, if and only if the requested
+   precision can be established). */
+int
+fesetprec (int prec)
+{
+  unsigned short cw;
+
+  /* Will succeed for any valid value of the input parameter.  */
+  switch (prec)
+    {
+    case FE_FLTPREC:
+    case FE_DBLPREC:
+    case FE_LDBLPREC:
+      break;
+    default:
+      return 0;
+    }
+
+  /* Get control word.  */
+  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
+
+  /* Twiddle bits.  */
+  cw &= ~FE_CW_PREC_MASK;
+  cw |= (prec << FE_CW_PREC_SHIFT);
+
+  /* Set back into FPU state.  */
+  __asm__ volatile ("fldcw %0" :: "m" (cw));
+
+  /* Indicate success.  */
+  return 1;
+}
+#endif
+
+/*  Set up the FPU and SSE environment at the start of execution.  */
+static void
+_feinitialise (void)
+{
+  extern fenv_t __fe_dfl_env;
+
+  /* Reset FPU: extended prec, all exceptions cleared and masked off.  */
+  __asm__ volatile ("fninit");
+  /* The default cw value, 0x37f, is rounding mode zero.  The MXCSR has
+     no precision control, so the only thing to do is set the exception
+     mask bits.  */
+
+  /* initialize the MXCSR register: mask all exceptions */
+  unsigned int mxcsr = __FE_ALL_EXCEPT_X86 << FE_SSE_EXCEPT_MASK_SHIFT;
+  if (use_sse())
+    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
+
+  /* Setup unmasked environment, but leave __FE_DENORM masked.  */
+  feenableexcept (FE_ALL_EXCEPT);
+  fegetenv (&fe_nomask_env);
+
+  /* Restore default exception masking (all masked).  */
+  fedisableexcept (FE_ALL_EXCEPT);
+
+  /* Finally cache state as default environment. */
+  fegetenv (&__fe_dfl_env);
+}
diff --git a/newlib/libm/machine/x86_64/fenv.c b/newlib/libm/machine/x86_64/fenv.c
index ccc08e2d8..4679f03e1 100644
--- a/newlib/libm/machine/x86_64/fenv.c
+++ b/newlib/libm/machine/x86_64/fenv.c
@@ -1,477 +1,7 @@
 /*
  * SPDX-License-Identifier: BSD-2-Clause
  *
- * Copyright (c) 2010-2019 Red Hat, Inc.
+ * (c) Copyright 2019 Joel Sherrill <joel@rtems.org>
  */
 
-#define _GNU_SOURCE        // for FE_NOMASK_ENV
-
-#include <fenv.h>
-#include <errno.h>
-#include <string.h>        // for memcpy 
-#include <stdbool.h>
-
-/*  x87 supports subnormal numbers so we need it below. */
-#define __FE_DENORM	(1 << 1)
-/* mask (= 0x3f) to disable all exceptions at initialization */
-#define __FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM)
-
-/*  Mask and shift amount for rounding bits.  */
-#define FE_CW_ROUND_MASK	(0x0c00)
-#define FE_CW_ROUND_SHIFT	(10)
-/*  Same, for SSE MXCSR.  */
-#define FE_MXCSR_ROUND_MASK	(0x6000)
-#define FE_MXCSR_ROUND_SHIFT	(13)
-
-/*  Mask and shift amount for precision bits.  */
-#define FE_CW_PREC_MASK		(0x0300)
-#define FE_CW_PREC_SHIFT	(8)
-
-/*  In x87, exception status bits and mask bits occupy
-   corresponding bit positions in the status and control
-   registers, respectively.  In SSE, they are both located
-   in the control-and-status register, with the status bits
-   corresponding to the x87 positions, and the mask bits
-   shifted by this amount to the left.  */
-#define FE_SSE_EXCEPT_MASK_SHIFT (7)
-
-/* These are writable so we can initialise them at startup.  */
-static fenv_t fe_nomask_env;
-
-/* These pointers provide the outside world with read-only access to them.  */
-const fenv_t *_fe_nomask_env = &fe_nomask_env;
-
-/* Assume i686 or above (hence SSE available) these days, with the
-   compiler feels free to use it (depending on compile- time flags of
-   course), but we should avoid needlessly breaking any purely integer mode
-   apps (or apps compiled with -mno-sse), so we only manage SSE state in this
-   fenv module if we detect that SSE instructions are available at runtime.
-   If we didn't do this, all applications run on older machines would bomb
-   out with an invalid instruction exception right at startup; let's not
-   be *that* WJM!  */
-static inline bool use_sse(void)
-{
-  unsigned int edx, eax;
-
-  /* Check for presence of SSE: invoke CPUID #1, check EDX bit 25.  */
-  eax = 1;
-  __asm__ volatile ("cpuid" : "=d" (edx), "+a" (eax) :: "%ecx", "%ebx");
-  /* If this flag isn't set we'll avoid trying to execute any SSE.  */
-  if ((edx & (1 << 25)) != 0)
-    return true;
-
-  return false;
-}
-
-/* forward declaration */
-static void _feinitialise (void);
-
-/*  This function enables traps for each of the exceptions as indicated
-   by the parameter except. The individual exceptions are described in
-   [ ... glibc manual xref elided ...]. Only the specified exceptions are
-   enabled, the status of the other exceptions is not changed.
-    The function returns the previous enabled exceptions in case the
-   operation was successful, -1 otherwise.  */
-int
-feenableexcept (int excepts)
-{
-  unsigned short cw, old_cw;
-  unsigned int mxcsr = 0;
-
-  if (excepts & ~FE_ALL_EXCEPT)
-    return -1;
-
-  /* Get control words.  */
-  __asm__ volatile ("fnstcw %0" : "=m" (old_cw) : );
-  if (use_sse())
-    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
-
-  /* Enable exceptions by clearing mask bits.  */
-  cw = old_cw & ~excepts;
-  mxcsr &= ~(excepts << FE_SSE_EXCEPT_MASK_SHIFT);
-
-  /* Store updated control words.  */
-  __asm__ volatile ("fldcw %0" :: "m" (cw));
-  if (use_sse())
-    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
-
-  /* Return old value.  We assume SSE and x87 stay in sync.  Note that
-     we are returning a mask of enabled exceptions, which is the opposite
-     of the flags in the register, which are set to disable (mask) their
-     related exceptions.  */
-  return (~old_cw) & FE_ALL_EXCEPT;
-}
-
-/*  This function disables traps for each of the exceptions as indicated
-   by the parameter except. The individual exceptions are described in
-   [ ... glibc manual xref elided ...]. Only the specified exceptions are
-   disabled, the status of the other exceptions is not changed.
-    The function returns the previous enabled exceptions in case the
-   operation was successful, -1 otherwise.  */
-int
-fedisableexcept (int excepts)
-{
-  unsigned short cw, old_cw;
-  unsigned int mxcsr = 0;
-
-  if (excepts & ~FE_ALL_EXCEPT)
-    return -1;
-
-  /* Get control words.  */
-  __asm__ volatile ("fnstcw %0" : "=m" (old_cw) : );
-  if (use_sse())
-    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
-
-  /* Disable exceptions by setting mask bits.  */
-  cw = old_cw | excepts;
-  mxcsr |= (excepts << FE_SSE_EXCEPT_MASK_SHIFT);
-
-  /* Store updated control words.  */
-  __asm__ volatile ("fldcw %0" :: "m" (cw));
-  if (use_sse())
-    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
-
-  /* Return old value.  We assume SSE and x87 stay in sync.  Note that
-     we are returning a mask of enabled exceptions, which is the opposite
-     of the flags in the register, which are set to disable (mask) their
-     related exceptions.  */
-  return (~old_cw) & FE_ALL_EXCEPT;
-}
-
-/*  This function returns a bitmask of all currently enabled exceptions. It
-   returns -1 in case of failure.  */
-int
-fegetexcept (void)
-{
-  unsigned short cw;
-
-  /* Get control word.  We assume SSE and x87 stay in sync.  */
-  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
-
-  /* Exception is *dis*abled when mask bit is set.  */
-  return (~cw) & FE_ALL_EXCEPT;
-}
-
-/*  Store the floating-point environment in the variable pointed to by envp.
-   The function returns zero in case the operation was successful, a non-zero
-   value otherwise.  */
-int
-fegetenv (fenv_t *envp)
-{
-  /* fnstenv disables all exceptions in the x87 FPU; as this is not what is
-     desired here, reload the cfg saved from the x87 FPU, back to the FPU */
-  __asm__ volatile ("fnstenv %0\n\
-                     fldenv %0"
-		    : "=m" (envp->_fpu) : );
-  if (use_sse())
-    __asm__ volatile ("stmxcsr %0" : "=m" (envp->_sse_mxcsr) : );
-  return 0;
-}
-
-/*  Store the current floating-point environment in the object pointed to
-   by envp. Then clear all exception flags, and set the FPU to trap no
-   exceptions.  Not all FPUs support trapping no exceptions; if feholdexcept
-   cannot set this mode, it returns nonzero value.  If it succeeds, it
-   returns zero.  */
-int
-feholdexcept (fenv_t *envp)
-{
-  unsigned int mxcsr;
-  fegetenv (envp);
-  mxcsr = envp->_sse_mxcsr & ~FE_ALL_EXCEPT;
-  if (use_sse())
-    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
-  __asm__ volatile ("fnclex");
-  fedisableexcept (FE_ALL_EXCEPT);
-  return 0;
-}
-
-/*  Set the floating-point environment to that described by envp.  The
-   function returns zero in case the operation was successful, a non-zero
-   value otherwise.  */
-int
-fesetenv (const fenv_t *envp)
-{
-   if ((envp == FE_DFL_ENV || envp == FE_NOMASK_ENV) &&
-       envp->_fpu._fpu_cw == 0)
-     _feinitialise ();
-
-  __asm__ volatile ("fldenv %0" :: "m" (envp->_fpu) );
-  if (use_sse())
-    __asm__ volatile ("ldmxcsr %0" :: "m" (envp->_sse_mxcsr));
-  return 0;
-}
-
-/*  Like fesetenv, this function sets the floating-point environment to
-   that described by envp. However, if any exceptions were flagged in the
-   status word before feupdateenv was called, they remain flagged after
-   the call.  In other words, after feupdateenv is called, the status
-   word is the bitwise OR of the previous status word and the one saved
-   in envp.  The function returns zero in case the operation was successful,
-   a non-zero value otherwise.  */
-int
-feupdateenv (const fenv_t *envp)
-{
-  fenv_t envcopy;
-  unsigned int mxcsr = 0;
-  unsigned short sw;
-
-  /* Don't want to modify *envp, but want to update environment atomically,
-     so take a copy and merge the existing exceptions into it.  */
-  memcpy (&envcopy, envp, sizeof *envp);
-  __asm__ volatile ("fnstsw %0" : "=m" (sw) : );
-  if (use_sse())
-    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
-  envcopy._fpu._fpu_sw |= (sw & FE_ALL_EXCEPT);
-  envcopy._sse_mxcsr |= (mxcsr & FE_ALL_EXCEPT);
-
-  return fesetenv (&envcopy);
-}
-
-/*  This function clears all of the supported exception flags indicated by
-   excepts.  The function returns zero in case the operation was successful,
-   a non-zero value otherwise.  */
-int
-feclearexcept (int excepts)
-{
-  fenv_t fenv;
-
-  if (excepts & ~FE_ALL_EXCEPT)
-    return EINVAL;
-
-  /* Need to save/restore whole environment to modify status word.  */
-  fegetenv (&fenv);
-
-  /* Mask undesired bits out.  */
-  fenv._fpu._fpu_sw &= ~excepts;
-  fenv._sse_mxcsr &= ~excepts;
-
-  /* Set back into FPU state.  */
-  return fesetenv (&fenv);
-}
-
-/*  This function raises the supported exceptions indicated by
-   excepts.  If more than one exception bit in excepts is set the order
-   in which the exceptions are raised is undefined except that overflow
-   (FE_OVERFLOW) or underflow (FE_UNDERFLOW) are raised before inexact
-   (FE_INEXACT). Whether for overflow or underflow the inexact exception
-   is also raised is also implementation dependent.  The function returns
-   zero in case the operation was successful, a non-zero value otherwise.  */
-int
-feraiseexcept (int excepts)
-{
-  fenv_t fenv;
-
-  if (excepts & ~FE_ALL_EXCEPT)
-    return EINVAL;
-
-  /* Need to save/restore whole environment to modify status word.  */
-  __asm__ volatile ("fnstenv %0" : "=m" (fenv) : );
-
-  /* Set desired exception bits.  */
-  fenv._fpu._fpu_sw |= excepts;
-
-  /* Set back into FPU state.  */
-  __asm__ volatile ("fldenv %0" :: "m" (fenv));
-
-  /* And trigger them - whichever are unmasked.  */
-  __asm__ volatile ("fwait");
-
-  return 0;
-}
-
-/*  Test whether the exception flags indicated by the parameter except
-   are currently set. If any of them are, a nonzero value is returned
-   which specifies which exceptions are set. Otherwise the result is zero.  */
-int
-fetestexcept (int excepts)
-{
-  unsigned short sw;
-  unsigned int mxcsr = 0;
-
-  if (excepts & ~FE_ALL_EXCEPT)
-    return EINVAL;
-
-  /* Get status registers.  */
-  __asm__ volatile ("fnstsw %0" : "=m" (sw) : );
-  if (use_sse())
-    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
-
-  /* Mask undesired bits out and return result.  */
-  return (sw | mxcsr) & excepts;
-}
-/*  This function stores in the variable pointed to by flagp an
-   implementation-defined value representing the current setting of the
-   exception flags indicated by excepts.  The function returns zero in
-   case the operation was successful, a non-zero value otherwise.  */
-int
-fegetexceptflag (fexcept_t *flagp, int excepts)
-{
-  unsigned short sw;
-  unsigned int mxcsr = 0;
-
-  if (excepts & ~FE_ALL_EXCEPT)
-    return EINVAL;
-
-  /* Get status registers.  */
-  __asm__ volatile ("fnstsw %0" : "=m" (sw) : );
-  if (use_sse())
-    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
-
-  /* Mask undesired bits out and set result.  */
-  *flagp = (sw | mxcsr) & excepts;
-
-  return 0;
-}
-
-/*  This function restores the flags for the exceptions indicated by
-   excepts to the values stored in the variable pointed to by flagp.  */
-int
-fesetexceptflag (const fexcept_t *flagp, int excepts)
-{
-  fenv_t fenv;
-
-  if (excepts & ~FE_ALL_EXCEPT)
-    return EINVAL;
-
-  /* Need to save/restore whole environment to modify status word.  */
-  fegetenv (&fenv);
-
-  /* Set/Clear desired exception bits.  */
-  fenv._fpu._fpu_sw &= ~excepts;
-  fenv._fpu._fpu_sw |= excepts & *flagp;
-  fenv._sse_mxcsr &= ~excepts;
-  fenv._sse_mxcsr |= excepts & *flagp;
-
-  /* Set back into FPU state.  */
-  return fesetenv (&fenv);
-}
-
-/*  Returns the currently selected rounding mode, represented by one of the
-   values of the defined rounding mode macros.  */
-int
-fegetround (void)
-{
-  unsigned short cw;
-
-  /* Get control word.  We assume SSE and x87 stay in sync.  */
-  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
-
-  return (cw & FE_CW_ROUND_MASK) >> FE_CW_ROUND_SHIFT;
-}
-
-/*  Changes the currently selected rounding mode to round. If round does
-   not correspond to one of the supported rounding modes nothing is changed.
-   fesetround returns zero if it changed the rounding mode, a nonzero value
-   if the mode is not supported.  */
-int
-fesetround (int round)
-{
-  unsigned short cw;
-  unsigned int mxcsr = 0;
-
-  /* Will succeed for any valid value of the input parameter.  */
-  if (round < FE_TONEAREST || round > FE_TOWARDZERO)
-    return EINVAL;
-
-  /* Get control words.  */
-  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
-  if (use_sse())
-    __asm__ volatile ("stmxcsr %0" : "=m" (mxcsr) : );
-
-  /* Twiddle bits.  */
-  cw &= ~FE_CW_ROUND_MASK;
-  cw |= (round << FE_CW_ROUND_SHIFT);
-  mxcsr &= ~FE_MXCSR_ROUND_MASK;
-  mxcsr |= (round << FE_MXCSR_ROUND_SHIFT);
-
-  /* Set back into FPU state.  */
-  __asm__ volatile ("fldcw %0" :: "m" (cw));
-  if (use_sse())
-    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
-
-  /* Indicate success.  */
-  return 0;
-}
-
-#if defined(__CYGWIN__)
-/*  Returns the currently selected precision, represented by one of the
-   values of the defined precision macros.  */
-int
-fegetprec (void)
-{
-  unsigned short cw;
-
-  /* Get control word.  */
-  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
-
-  return (cw & FE_CW_PREC_MASK) >> FE_CW_PREC_SHIFT;
-}
-
-/* http://www.open-std.org/jtc1/sc22//WG14/www/docs/n752.htm:
-
-   The fesetprec function establishes the precision represented by its
-   argument prec.  If the argument does not match a precision macro, the
-   precision is not changed.
-
-   The fesetprec function returns a nonzero value if and only if the
-   argument matches a precision macro (that is, if and only if the requested
-   precision can be established). */
-int
-fesetprec (int prec)
-{
-  unsigned short cw;
-
-  /* Will succeed for any valid value of the input parameter.  */
-  switch (prec)
-    {
-    case FE_FLTPREC:
-    case FE_DBLPREC:
-    case FE_LDBLPREC:
-      break;
-    default:
-      return 0;
-    }
-
-  /* Get control word.  */
-  __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
-
-  /* Twiddle bits.  */
-  cw &= ~FE_CW_PREC_MASK;
-  cw |= (prec << FE_CW_PREC_SHIFT);
-
-  /* Set back into FPU state.  */
-  __asm__ volatile ("fldcw %0" :: "m" (cw));
-
-  /* Indicate success.  */
-  return 1;
-}
-#endif
-
-/*  Set up the FPU and SSE environment at the start of execution.  */
-static void
-_feinitialise (void)
-{
-  extern fenv_t __fe_dfl_env;
-
-  /* Reset FPU: extended prec, all exceptions cleared and masked off.  */
-  __asm__ volatile ("fninit");
-  /* The default cw value, 0x37f, is rounding mode zero.  The MXCSR has
-     no precision control, so the only thing to do is set the exception
-     mask bits.  */
-
-  /* initialize the MXCSR register: mask all exceptions */
-  unsigned int mxcsr = __FE_ALL_EXCEPT_X86 << FE_SSE_EXCEPT_MASK_SHIFT;
-  if (use_sse())
-    __asm__ volatile ("ldmxcsr %0" :: "m" (mxcsr));
-
-  /* Setup unmasked environment, but leave __FE_DENORM masked.  */
-  feenableexcept (FE_ALL_EXCEPT);
-  fegetenv (&fe_nomask_env);
-
-  /* Restore default exception masking (all masked).  */
-  fedisableexcept (FE_ALL_EXCEPT);
-
-  /* Finally cache state as default environment. */
-  fegetenv (&__fe_dfl_env);
-}
+#include "../shared_x86/fenv.c"