svn commit: r275518 - head/lib/msun/src

[Steve Kargl]

Author: kargl
Date: Fri Dec  5 19:00:55 2014
New Revision: 275518
URL: https://svnweb.freebsd.org/changeset/base/275518

Log:
  Update the constants associated with the evaluation of j0f(x)
  for |x| small.
  
  While here, remove the explicit cast of 0.25 to float.  Replace
  a multiplication involving 0.25 by a division using an integer
  constant 4.  Make a similar change in j0() to minimize the diff.
  
  Suggested by:	bde

Modified:
  head/lib/msun/src/e_j0.c
  head/lib/msun/src/e_j0f.c

Modified: head/lib/msun/src/e_j0.c
==============================================================================
--- head/lib/msun/src/e_j0.c	Fri Dec  5 18:55:32 2014	(r275517)
+++ head/lib/msun/src/e_j0.c	Fri Dec  5 19:00:55 2014	(r275518)
@@ -115,7 +115,7 @@ __ieee754_j0(double x)
 	if(ix<0x3f200000) {	/* |x| < 2**-13 */
 	    if(huge+x>one) {	/* raise inexact if x != 0 */
 	        if(ix<0x3e400000) return one;	/* |x|<2**-27 */
-	        else 	      return one - 0.25*x*x;
+	        else 	      return one - x*x/4;
 	    }
 	}
 	z = x*x;

Modified: head/lib/msun/src/e_j0f.c
==============================================================================
--- head/lib/msun/src/e_j0f.c	Fri Dec  5 18:55:32 2014	(r275517)
+++ head/lib/msun/src/e_j0f.c	Fri Dec  5 19:00:55 2014	(r275518)
@@ -69,10 +69,10 @@ __ieee754_j0f(float x)
 		}
 		return z;
 	}
-	if(ix<0x39000000) {	/* |x| < 2**-13 */
+	if(ix<0x3c000000) {	/* |x| < 2**-7 */
 	    if(huge+x>one) {	/* raise inexact if x != 0 */
-	        if(ix<0x32000000) return one;	/* |x|<2**-27 */
-	        else 	      return one - (float)0.25*x*x;
+	        if(ix<0x39800000) return one;	/* |x|<2**-12 */
+	        else 	      return one - x*x/4;
 	    }
 	}
 	z = x*x;