diff --git a/lib/libc/ia64/_fpmath.h b/lib/libc/ia64/_fpmath.h
index 80ea88a6bb98..33e6a3209ab0 100644
--- a/lib/libc/ia64/_fpmath.h
+++ b/lib/libc/ia64/_fpmath.h
@@ -27,14 +27,29 @@
  * $FreeBSD$
  */
 
+#include <sys/endian.h>
+
 union IEEEl2bits {
 	long double	e;
 	struct {
-		unsigned long	manl	:64;
-		unsigned long	manh	:48;
+#if _BYTE_ORDER == _LITTLE_ENDIAN
+		unsigned int	manl	:32;
+		unsigned int	manh	:32;
 		unsigned int	exp	:15;
 		unsigned int	sign	:1;
+		unsigned long	junk	:48;
+#else /* _BIG_ENDIAN */
+		unsigned long	junk	:48;
+		unsigned int	sign	:1;
+		unsigned int	exp	:15;
+		unsigned int	manh	:32;
+		unsigned int	manl	:32;
+#endif
 	} bits;
 };
 
-#define	mask_nbit_l(u)	((u).bits.manl &= 0x7fffffffffffffff)
+#if _BYTE_ORDER == _LITTLE_ENDIAN
+#define	mask_nbit_l(u)	((u).bits.manh &= 0x7fffffff)
+#else /* _BIG_ENDIAN */
+#define	mask_nbit_l(u)	((u).bits.manh &= 0xffffff7f)
+#endif
diff --git a/lib/libc/ia64/gen/infinity.c b/lib/libc/ia64/gen/infinity.c
index ac7fc38b65cb..1ae92a804d55 100644
--- a/lib/libc/ia64/gen/infinity.c
+++ b/lib/libc/ia64/gen/infinity.c
@@ -30,10 +30,19 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <sys/endian.h>
 #include <math.h>
 
 /* bytes for +Infinity on an ia64 (IEEE double format) */
+#if _BYTE_ORDER == _LITTLE_ENDIAN
 const union __infinity_un __infinity = { { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f } };
+#else /* _BIG_ENDIAN */
+const union __infinity_un __infinity = { { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 } };
+#endif
 
 /* bytes for NaN */
+#if _BYTE_ORDER == _LITTLE_ENDIAN
 const union __nan_un __nan = { { 0, 0, 0xc0, 0xff } };
+#else /* _BIG_ENDIAN */
+const union __nan_un __nan = { { 0xff, 0xc0, 0, 0 } };
+#endif