commit c95b3011018893fcc473279768a67a24a73bbef2

Author: Wilco <wdijkstr@arm.com>

Date:   Mon Jun 2 12:20:17 2014 +0100

    [AArch64] Rewrite feupdateenv (BZ 17009).

diff --git a/ports/sysdeps/aarch64/fpu/feupdateenv.c b/ports/sysdeps/aarch64/fpu/feupdateenv.c

index 6d64a9b..ac2f6fe 100644

--- a/ports/sysdeps/aarch64/fpu/feupdateenv.c

+++ b/ports/sysdeps/aarch64/fpu/feupdateenv.c

@@ -22,16 +22,65 @@

 int

 feupdateenv (const fenv_t *envp)

 {

+  fpu_control_t fpcr;

+  fpu_control_t fpcr_new;

+  fpu_control_t updated_fpcr;

   fpu_fpsr_t fpsr;

+  fpu_fpsr_t fpsr_new;

+  int excepts;

-  /* Get the current exception state.  */

+  _FPU_GETCW (fpcr);

   _FPU_GETFPSR (fpsr);

+  excepts = fpsr & FE_ALL_EXCEPT;

-  /* Install new environment.  */

-  fesetenv (envp);

+  if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))

+    {

+      fpcr_new = envp->__fpcr;

+      fpsr_new = envp->__fpsr | excepts;

-  /* Raise the saved exceptions.  */

-  feraiseexcept (fpsr & FE_ALL_EXCEPT);

+      if (fpcr != fpcr_new)

+        _FPU_SETCW (fpcr_new);

+

+      if (fpsr != fpsr_new)

+        _FPU_SETFPSR (fpsr_new);

+

+      if (excepts & (fpcr_new >> FE_EXCEPT_SHIFT))

+        return feraiseexcept (excepts);

+

+      return 0;

+    }

+

+  fpcr_new = fpcr & _FPU_RESERVED;

+  fpsr_new = fpsr & (_FPU_FPSR_RESERVED | FE_ALL_EXCEPT);

+

+  if (envp == FE_DFL_ENV)

+    {

+      fpcr_new |= _FPU_DEFAULT;

+      fpsr_new |= _FPU_FPSR_DEFAULT;

+    }

+  else

+    {

+      fpcr_new |= _FPU_FPCR_IEEE;

+      fpsr_new |= _FPU_FPSR_IEEE;

+    }

+

+  _FPU_SETFPSR (fpsr_new);

+

+  if (fpcr != fpcr_new)

+    {

+      _FPU_SETCW (fpcr_new);

+

+      /* Trapping exceptions are optional in AArch64; the relevant enable

+	 bits in FPCR are RES0 hence the absence of support can be detected

+	 by reading back the FPCR and comparing with the required value.  */

+      _FPU_GETCW (updated_fpcr);

+

+      if (fpcr_new & ~updated_fpcr)

+        return 1;

+    }

+

+  if (excepts & (fpcr_new >> FE_EXCEPT_SHIFT))

+    return feraiseexcept (excepts);

   return 0;

 }