summaryrefslogtreecommitdiff
path: root/newlib/libm/math/e_remainder.c
diff options
context:
space:
mode:
authorChristopher Faylor <me+cygwin@cgf.cx>2000-02-17 19:39:46 +0000
committerChristopher Faylor <me+cygwin@cgf.cx>2000-02-17 19:39:46 +0000
commit43b55bace5fad27af5da7a99784667363b92c45d (patch)
tree17fe82f6ba0d93b76d10dd73d4945ab81b69db40 /newlib/libm/math/e_remainder.c
parent8dabd7496a9eeaca2a7180c0a176059ba9229bb2 (diff)
downloadgdb-SNAPSHOT.tar.gz
import newlib-2000-02-17 snapshotnewlib-2000-02-17SNAPSHOT
Diffstat (limited to 'newlib/libm/math/e_remainder.c')
-rw-r--r--newlib/libm/math/e_remainder.c80
1 files changed, 80 insertions, 0 deletions
diff --git a/newlib/libm/math/e_remainder.c b/newlib/libm/math/e_remainder.c
new file mode 100644
index 00000000000..ae7ce649ad5
--- /dev/null
+++ b/newlib/libm/math/e_remainder.c
@@ -0,0 +1,80 @@
+
+/* @(#)e_remainder.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, 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 fmod() return x-[x/p]chopped*p exactlp.
+ */
+
+#include "fdlibm.h"
+
+#ifndef _DOUBLE_IS_32BITS
+
+#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
+{
+ __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 = __ieee754_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;
+}
+
+#endif /* defined(_DOUBLE_IS_32BITS) */