Use the FP_ILOG macros from <math.h> rather than hardcoded return values.

Also be prepared for FP_ILOGBNAN != INT_MAX.

Reviewed by:	md5

2 files changed, 13 insertions, 6 deletions

diff --git a/lib/msun/src/s_ilogb.c b/lib/msun/src/s_ilogb.c
index ef24efa..69077af 100644
--- a/lib/msun/src/s_ilogb.c
+++ b/lib/msun/src/s_ilogb.c
@@ -16,10 +16,13 @@ static char rcsid[] = "$FreeBSD$";
 
 /* ilogb(double x)
  * return the binary exponent of non-zero x
- * ilogb(0) = 0x80000001
- * ilogb(inf/NaN) = 0x7fffffff (no signal is raised)
+ * ilogb(0) = FP_ILOGB0
+ * ilogb(NaN) = FP_ILOGBNAN (no signal is raised)
+ * ilogb(inf) = INT_MAX (no signal is raised)
  */
 
+#include <limits.h>
+
 #include "math.h"
 #include "math_private.h"
 
@@ -31,7 +34,7 @@ static char rcsid[] = "$FreeBSD$";
 	hx &= 0x7fffffff;
 	if(hx<0x00100000) {
 	    if((hx|lx)==0)
-		return 0x80000001;	/* ilogb(0) = 0x80000001 */
+		return FP_ILOGB0;
 	    else			/* subnormal x */
 		if(hx==0) {
 		    for (ix = -1043; lx>0; lx<<=1) ix -=1;
@@ -41,5 +44,6 @@ static char rcsid[] = "$FreeBSD$";
 	    return ix;
 	}
 	else if (hx<0x7ff00000) return (hx>>20)-1023;
-	else return 0x7fffffff;
+	else if (hx>0x7ff00000 || lx!=0) return FP_ILOGBNAN;
+	else return INT_MAX;
 }
diff --git a/lib/msun/src/s_ilogbf.c b/lib/msun/src/s_ilogbf.c
index b65a365..ff58813 100644
--- a/lib/msun/src/s_ilogbf.c
+++ b/lib/msun/src/s_ilogbf.c
@@ -17,6 +17,8 @@
 static char rcsid[] = "$FreeBSD$";
 #endif
 
+#include <limits.h>
+
 #include "math.h"
 #include "math_private.h"
 
@@ -28,11 +30,12 @@ static char rcsid[] = "$FreeBSD$";
 	hx &= 0x7fffffff;
 	if(hx<0x00800000) {
 	    if(hx==0)
-		return 0x80000001;	/* ilogb(0) = 0x80000001 */
+		return FP_ILOGB0;
 	    else			/* subnormal x */
 	        for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
 	    return ix;
 	}
 	else if (hx<0x7f800000) return (hx>>23)-127;
-	else return 0x7fffffff;
+	else if (hx>0x7f800000) return FP_ILOGBNAN;
+	else return INT_MAX;
 }