diff --git a/src/libc/gen/modf.c b/src/libc/gen/modf.c
index a9ee6f3..33529c7 100644
--- a/src/libc/gen/modf.c
+++ b/src/libc/gen/modf.c
@@ -7,26 +7,7 @@
  * is preserved.
  */
 #include <math.h>
-
-// IM: dereferencing type-punned pointer will break strict-aliasing rules
-// TODO check Endiannes
-        union {
-              double d64;
-              struct { long i32h;
-                       long i32l;
-                     };
-        } ew;
-
-/* Get two 32 bit ints from a double.  */
-
-//#define EXTRACT_WORDS(high,low,d) 
-//        high = *(unsigned long long*) &d; 
-//        low  = (*(unsigned long long*) &d) >> 32
-
-/* Set a double from two 32 bit ints.  */
-
-#define INSERT_WORDS(d,high,low) \
-        *(unsigned long long*) &(x) = (unsigned long long) (high) << 32 | (low)
+#include <ieee.h>
 
 /*
  * modf(double x, double *iptr)
@@ -44,14 +25,12 @@ double modf (double x, double *iptr)
 	long i0, i1, j0;
 	unsigned long i;
 
-	//EXTRACT_WORDS (i0, i1, x);
-    ew.d64 = x; i0 = ew.i32h; i1 = ew.i32l;
+	EXTRACT_WORDS (i0, i1, x);
     //
 	j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;	/* exponent of x */
 	if (j0 < 20) {				/* integer part in high x */
 		if (j0 < 0) {			/* |x|<1 */
-			//INSERT_WORDS (*iptr, i0 & 0x80000000, 0);
-            ew.i32h = i0 & 0x80000000; ew.i32l = 0; *iptr = ew.d64;
+			INSERT_WORDS (*iptr, i0 & 0x80000000, 0);
             //
 			/* *iptr = +-0 */
 			return x;
@@ -59,14 +38,12 @@ double modf (double x, double *iptr)
 			i = (0x000fffff) >> j0;
 			if (((i0 & i) | i1) == 0) {	/* x is integral */
 				*iptr = x;
-				//INSERT_WORDS (x, i0 & 0x80000000, 0);
-                ew.i32h = i0 & 0x80000000; ew.i32l = 0; x = ew.d64;
+				INSERT_WORDS (x, i0 & 0x80000000, 0);
                 //
 				/* return +-0 */
 				return x;
 			} else {
-				//INSERT_WORDS (*iptr, i0 & (~i), 0);
-                ew.i32h = i0 & (~i); ew.i32l = 0; *iptr = ew.d64;
+				INSERT_WORDS (*iptr, i0 & (~i), 0);
                 //
 				return x - *iptr;
 			}
@@ -77,8 +54,7 @@ double modf (double x, double *iptr)
 		if (j0 == 0x400 && ((i0 & 0xfffff) | i1))
 			return x * one;
 
-		//INSERT_WORDS (x, i0 & 0x80000000, 0);
-        ew.i32h = i0 & 0x80000000; ew.i32l = 0; x = ew.d64;
+		INSERT_WORDS (x, i0 & 0x80000000, 0);
         //
 		/* return +-0 */
 		return x;
@@ -86,14 +62,12 @@ double modf (double x, double *iptr)
 		i = ((unsigned long) (0xffffffff)) >> (j0 - 20);
 		if ((i1 & i) == 0) {			/* x is integral */
 			*iptr = x;
-			//INSERT_WORDS (x, i0 & 0x80000000, 0);
-            ew.i32h = i0 & 0x80000000; ew.i32l = 0; x = ew.d64;
+			INSERT_WORDS (x, i0 & 0x80000000, 0);
             //
 			/* return +-0 */
 			return x;
 		} else {
-			//INSERT_WORDS (*iptr, i0, i1 & (~i));
-            ew.i32h = i0; ew.i32l = i1 & (~i); *iptr = ew.d64;
+			INSERT_WORDS (*iptr, i0, i1 & (~i));
             //
 			return x - *iptr;
 		}