diff --git a/winsup/cygwin/fenv.cc b/winsup/cygwin/fenv.cc
index 066704b40..3adc8a954 100644
--- a/winsup/cygwin/fenv.cc
+++ b/winsup/cygwin/fenv.cc
@@ -12,6 +12,11 @@ details. */
 #include "wincap.h"
 #include <string.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)
@@ -417,7 +422,7 @@ fesetprec (int prec)
 void
 _feinitialise (void)
 {
-  unsigned int edx, eax, mxcsr;
+  unsigned int edx, eax;
 
   /* Check for presence of SSE: invoke CPUID #1, check EDX bit 25.  */
   eax = 1;
@@ -431,11 +436,13 @@ _feinitialise (void)
   /* 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.  */
-  mxcsr = FE_ALL_EXCEPT << FE_SSE_EXCEPT_MASK_SHIFT;
+
+  /* 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.  */
+  /* Setup unmasked environment, but leave __FE_DENORM masked.  */
   feenableexcept (FE_ALL_EXCEPT);
   fegetenv (&fe_nomask_env);
 
diff --git a/winsup/cygwin/include/fenv.h b/winsup/cygwin/include/fenv.h
index 7ec5d4d7d..7ce3a9340 100644
--- a/winsup/cygwin/include/fenv.h
+++ b/winsup/cygwin/include/fenv.h
@@ -87,16 +87,13 @@ typedef __uint32_t fexcept_t;
 #define FE_OVERFLOW	(1 << 3)
 #define FE_UNDERFLOW	(1 << 4)
 
-/*  This is not defined by Posix, but since x87 supports it we provide
-   a definition according to the same naming scheme used above.  */
-#define FE_DENORMAL	(1 << 1)
-
 /*  The <fenv.h> header shall define the following constant, which is
    simply the bitwise-inclusive OR of all floating-point exception
    constants defined above:  */
 
-#define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_INEXACT | FE_INVALID \
-			| FE_OVERFLOW | FE_UNDERFLOW | FE_DENORMAL)
+/* in agreement w/ Linux the subnormal exception will always be masked */
+#define FE_ALL_EXCEPT \
+  (FE_INEXACT | FE_UNDERFLOW | FE_OVERFLOW | FE_DIVBYZERO | FE_INVALID)
 
 /*  The <fenv.h> header shall define the following constants if and only
    if the implementation supports getting and setting the represented