Fix powl inaccuracy for ldbl-128ibm (bug 14914).

git-mirror · Dec 4, 2012 · b3b099a · b3b099a
1 parent a915e17
commit b3b099a
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Showing 3 changed files with 15 additions and 8 deletions.
diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,10 @@
+2012-12-04  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #14914]
+	* sysdeps/ieee754/ldbl-128ibm/e_powl.c (__ieee754_powl): Clear
+	whole low double instead of just low 47 bits when splitting values
+	into two parts.
+
 2012-12-03  Allan McRae  <allan@archlinux.org>
 
 	* manual/stdio.texi (Predefined Printf Handlers): Remove

diff --git a/NEWS b/NEWS
@@ -22,7 +22,7 @@ Version 2.17
   14661, 14669, 14672, 14683, 14694, 14716, 14719, 14743, 14767, 14783,
   14784, 14785, 14793, 14796, 14797, 14801, 14803, 14805, 14807, 14811,
   14815, 14821, 14822, 14824, 14828, 14831, 14835, 14838, 14856, 14863,
-  14865, 14866, 14868, 14869, 14871, 14879, 14889, 14893.
+  14865, 14866, 14868, 14869, 14871, 14879, 14889, 14893, 14914.
 
 * CVE-2011-4609 svc_run() produces high cpu usage when accept fails with
   EMFILE has been fixed (Bugzilla #14889).

diff --git a/sysdeps/ieee754/ldbl-128ibm/e_powl.c b/sysdeps/ieee754/ldbl-128ibm/e_powl.c
@@ -324,13 +324,13 @@ __ieee754_powl (long double x, long double y)
 
   o.value = s_h;
   o.parts32.w3 = 0;
-  o.parts32.w2 &= 0xffff8000;
+  o.parts32.w2 = 0;
   s_h = o.value;
   /* t_h=ax+bp[k] High */
   t_h = ax + bp[k];
   o.value = t_h;
   o.parts32.w3 = 0;
-  o.parts32.w2 &= 0xffff8000;
+  o.parts32.w2 = 0;
   t_h = o.value;
   t_l = ax - (t_h - bp[k]);
   s_l = v * ((u - s_h * t_h) - s_h * t_l);
@@ -344,7 +344,7 @@ __ieee754_powl (long double x, long double y)
   t_h = 3.0 + s2 + r;
   o.value = t_h;
   o.parts32.w3 = 0;
-  o.parts32.w2 &= 0xffff8000;
+  o.parts32.w2 = 0;
   t_h = o.value;
   t_l = r - ((t_h - 3.0) - s2);
   /* u+v = s*(1+...) */
@@ -354,7 +354,7 @@ __ieee754_powl (long double x, long double y)
   p_h = u + v;
   o.value = p_h;
   o.parts32.w3 = 0;
-  o.parts32.w2 &= 0xffff8000;
+  o.parts32.w2 = 0;
   p_h = o.value;
   p_l = v - (p_h - u);
   z_h = cp_h * p_h;		/* cp_h+cp_l = 2/(3*log2) */
@@ -364,7 +364,7 @@ __ieee754_powl (long double x, long double y)
   t1 = (((z_h + z_l) + dp_h[k]) + t);
   o.value = t1;
   o.parts32.w3 = 0;
-  o.parts32.w2 &= 0xffff8000;
+  o.parts32.w2 = 0;
   t1 = o.value;
   t2 = z_l - (((t1 - t) - dp_h[k]) - z_h);
 
@@ -377,7 +377,7 @@ __ieee754_powl (long double x, long double y)
   y1 = y;
   o.value = y1;
   o.parts32.w3 = 0;
-  o.parts32.w2 &= 0xffff8000;
+  o.parts32.w2 = 0;
   y1 = o.value;
   p_l = (y - y1) * t1 + y * t2;
   p_h = y1 * t1;
@@ -421,7 +421,7 @@ __ieee754_powl (long double x, long double y)
   t = p_l + p_h;
   o.value = t;
   o.parts32.w3 = 0;
-  o.parts32.w2 &= 0xffff8000;
+  o.parts32.w2 = 0;
   t = o.value;
   u = t * lg2_h;
   v = (p_l - (t - p_h)) * lg2 + t * lg2_l;