diff --git a/lib/msun/amd64/fenv.c b/lib/msun/amd64/fenv.c
index bd267e5bd51d..8b49b35c3eec 100644
--- a/lib/msun/amd64/fenv.c
+++ b/lib/msun/amd64/fenv.c
@@ -135,12 +135,12 @@ __feenableexcept(int mask)
 	mask &= FE_ALL_EXCEPT;
 	__fnstcw(&control);
 	__stmxcsr(&mxcsr);
-	omask = (control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
+	omask = ~(control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
 	control &= ~mask;
 	__fldcw(control);
 	mxcsr &= ~(mask << _SSE_EMASK_SHIFT);
 	__ldmxcsr(mxcsr);
-	return (~omask);
+	return (omask);
 }
 
 int
@@ -152,12 +152,12 @@ __fedisableexcept(int mask)
 	mask &= FE_ALL_EXCEPT;
 	__fnstcw(&control);
 	__stmxcsr(&mxcsr);
-	omask = (control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
+	omask = ~(control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
 	control |= mask;
 	__fldcw(control);
 	mxcsr |= mask << _SSE_EMASK_SHIFT;
 	__ldmxcsr(mxcsr);
-	return (~omask);
+	return (omask);
 }
 
 __weak_reference(__feenableexcept, feenableexcept);
diff --git a/lib/msun/i387/fenv.c b/lib/msun/i387/fenv.c
index fafe2204cd19..6f51ba24a0f7 100644
--- a/lib/msun/i387/fenv.c
+++ b/lib/msun/i387/fenv.c
@@ -192,14 +192,14 @@ __feenableexcept(int mask)
 		__stmxcsr(&mxcsr);
 	else
 		mxcsr = 0;
-	omask = (control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
+	omask = ~(control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
 	control &= ~mask;
 	__fldcw(control);
 	if (__HAS_SSE()) {
 		mxcsr &= ~(mask << _SSE_EMASK_SHIFT);
 		__ldmxcsr(mxcsr);
 	}
-	return (~omask);
+	return (omask);
 }
 
 int
@@ -214,14 +214,14 @@ __fedisableexcept(int mask)
 		__stmxcsr(&mxcsr);
 	else
 		mxcsr = 0;
-	omask = (control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
+	omask = ~(control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
 	control |= mask;
 	__fldcw(control);
 	if (__HAS_SSE()) {
 		mxcsr |= mask << _SSE_EMASK_SHIFT;
 		__ldmxcsr(mxcsr);
 	}
-	return (~omask);
+	return (omask);
 }
 
 __weak_reference(__feenableexcept, feenableexcept);