initial check-in, version 0.5.0 v0.5.0

1 files changed, 69 insertions, 0 deletions

diff --git a/src/math/e_remainder.c b/src/math/e_remainder.c
new file mode 100644
index 00000000..9cb56919
--- /dev/null
+++ b/src/math/e_remainder.c
@@ -0,0 +1,69 @@
+
+/* @(#)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.
+ * ====================================================
+ */
+
+/* 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 fmod() return x-[x/p]chopped*p exactlp.
+ */
+
+#include <math.h>
+#include "math_private.h"
+
+static const double zero = 0.0;
+
+
+double
+remainder(double x, double p)
+{
+        int32_t hx,hp;
+        uint32_t sx,lx,lp;
+        double p_half;
+
+        EXTRACT_WORDS(hx,lx,x);
+        EXTRACT_WORDS(hp,lp,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 = fmod(x,p+p);  /* now x < 2p */
+        if (((hx-hp)|(lx-lp))==0) return zero*x;
+        x  = fabs(x);
+        p  = 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;
+            }
+        }
+        GET_HIGH_WORD(hx,x);
+        SET_HIGH_WORD(x,hx^sx);
+        return x;
+}