aboutsummaryrefslogtreecommitdiff
path: root/e_remainder.c
diff options
context:
space:
mode:
authorThe Android Open Source Project <initial-contribution@android.com>2008-10-21 07:00:00 -0700
committerThe Android Open Source Project <initial-contribution@android.com>2008-10-21 07:00:00 -0700
commit8771baa10b2dc5bbedb08231d99c72cfd6abcb5b (patch)
tree87dbea36a0e5ed0f2f8e2a499b9c1014af6a38b5 /e_remainder.c
downloadfdlibm-8771baa10b2dc5bbedb08231d99c72cfd6abcb5b.tar.gz
Diffstat (limited to 'e_remainder.c')
-rw-r--r--e_remainder.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/e_remainder.c b/e_remainder.c
new file mode 100644
index 0000000..6de2135
--- /dev/null
+++ b/e_remainder.c
@@ -0,0 +1,77 @@
+
+/* @(#)e_remainder.c 1.3 95/01/18 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+/* __ieee754_remainder(x,p)
+ * Return :
+ * returns x REM p = x - [x/p]*p as if in infinite
+ * precise arithmetic, where [x/p] is the (infinite bit)
+ * integer nearest x/p (in half way case choose the even one).
+ * Method :
+ * Based on ieee_fmod() return x-[x/p]chopped*p exactlp.
+ */
+
+#include "fdlibm.h"
+
+#ifdef __STDC__
+static const double zero = 0.0;
+#else
+static double zero = 0.0;
+#endif
+
+
+#ifdef __STDC__
+ double __ieee754_remainder(double x, double p)
+#else
+ double __ieee754_remainder(x,p)
+ double x,p;
+#endif
+{
+ int hx,hp;
+ unsigned sx,lx,lp;
+ double p_half;
+
+ hx = __HI(x); /* high word of x */
+ lx = __LO(x); /* low word of x */
+ hp = __HI(p); /* high word of p */
+ lp = __LO(p); /* low word of p */
+ sx = hx&0x80000000;
+ hp &= 0x7fffffff;
+ hx &= 0x7fffffff;
+
+ /* purge off exception values */
+ if((hp|lp)==0) return (x*p)/(x*p); /* p = 0 */
+ if((hx>=0x7ff00000)|| /* x not finite */
+ ((hp>=0x7ff00000)&& /* p is NaN */
+ (((hp-0x7ff00000)|lp)!=0)))
+ return (x*p)/(x*p);
+
+
+ if (hp<=0x7fdfffff) x = __ieee754_fmod(x,p+p); /* now x < 2p */
+ if (((hx-hp)|(lx-lp))==0) return zero*x;
+ x = ieee_fabs(x);
+ p = ieee_fabs(p);
+ if (hp<0x00200000) {
+ if(x+x>p) {
+ x-=p;
+ if(x+x>=p) x -= p;
+ }
+ } else {
+ p_half = 0.5*p;
+ if(x>p_half) {
+ x-=p;
+ if(x>=p_half) x -= p;
+ }
+ }
+ __HI(x) ^= sx;
+ return x;
+}