Optimize s_modf

1 files changed, 65 insertions, 0 deletions

diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_modf.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_modf.c
new file mode 100644
index 0000000000..0cba548abd
--- /dev/null
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_modf.c
@@ -0,0 +1,65 @@
+/* Rewritten for 64-bit machines by Ulrich Drepper <drepper@gmail.com>.  */
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+/*
+ * modf(double x, double *iptr)
+ * return fraction part of x, and return x's integral part in *iptr.
+ * Method:
+ *	Bit twiddling.
+ *
+ * Exception:
+ *	No exception.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+static const double one = 1.0;
+
+double
+__modf(double x, double *iptr)
+{
+	int64_t i0;
+	int32_t j0;
+	EXTRACT_WORDS64(i0,x);
+	j0 = ((i0>>52)&0x7ff)-0x3ff;	/* exponent of x */
+	if(j0<52) {			/* integer part in x */
+	    if(j0<0) {			/* |x|<1 */
+		/* *iptr = +-0 */
+		INSERT_WORDS64(*iptr,i0&UINT64_C(0x8000000000000000));
+		return x;
+	    } else {
+		uint64_t i = UINT64_C(0x000fffffffffffff)>>j0;
+		if((i0&i)==0) {		/* x is integral */
+		    *iptr = x;
+		    /* return +-0 */
+		    INSERT_WORDS64(x,i0&UINT64_C(0x8000000000000000));
+		    return x;
+		} else {
+		    INSERT_WORDS64(*iptr,i0&(~i));
+		    return x - *iptr;
+		}
+	    }
+	} else { /* no fraction part */
+	    *iptr = x*one;
+	    /* We must handle NaNs separately.  */
+	    if (j0 == 0x400 && (i0 & UINT64_C(0xfffffffffffff)))
+	      return x*one;
+	    INSERT_WORDS64(x,i0&UINT64_C(0x8000000000000000));	/* return +-0 */
+	    return x;
+	}
+}
+weak_alias (__modf, modf)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__modf, __modfl)
+weak_alias (__modf, modfl)
+#endif