Optimize s_modf

2 files changed, 70 insertions, 18 deletions

diff --git a/sysdeps/ieee754/dbl-64/s_modf.c b/sysdeps/ieee754/dbl-64/s_modf.c
index 7851f675a4..a884de5d5f 100644
--- a/sysdeps/ieee754/dbl-64/s_modf.c
+++ b/sysdeps/ieee754/dbl-64/s_modf.c
@@ -1,4 +1,3 @@
-/* @(#)s_modf.c 5.1 93/09/24 */
 /*
  * ====================================================
  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
@@ -10,10 +9,6 @@
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: s_modf.c,v 1.8 1995/05/10 20:47:55 jtc Exp $";
-#endif
-
 /*
  * modf(double x, double *iptr)
  * return fraction part of x, and return x's integral part in *iptr.
@@ -27,18 +22,10 @@ static char rcsid[] = "$NetBSD: s_modf.c,v 1.8 1995/05/10 20:47:55 jtc Exp $";
 #include "math.h"
 #include "math_private.h"
 
-#ifdef __STDC__
 static const double one = 1.0;
-#else
-static double one = 1.0;
-#endif
 
-#ifdef __STDC__
-	double __modf(double x, double *iptr)
-#else
-	double __modf(x, iptr)
-	double x,*iptr;
-#endif
+double
+__modf(double x, double *iptr)
 {
 	int32_t i0,i1,j0;
 	u_int32_t i;
@@ -46,7 +33,7 @@ static double one = 1.0;
 	j0 = ((i0>>20)&0x7ff)-0x3ff;	/* exponent of x */
 	if(j0<20) {			/* integer part in high x */
 	    if(j0<0) {			/* |x|<1 */
-	        INSERT_WORDS(*iptr,i0&0x80000000,0);	/* *iptr = +-0 */
+		INSERT_WORDS(*iptr,i0&0x80000000,0);	/* *iptr = +-0 */
 		return x;
 	    } else {
 		i = (0x000fffff)>>j0;
@@ -59,7 +46,7 @@ static double one = 1.0;
 		    return x - *iptr;
 		}
 	    }
-	} else if (j0>51) {		/* no fraction part */
+	} else if (__builtin_expect(j0>51, 0)) { /* no fraction part */
 	    *iptr = x*one;
 	    /* We must handle NaNs separately.  */
 	    if (j0 == 0x400 && ((i0 & 0xfffff) | i1))
@@ -73,7 +60,7 @@ static double one = 1.0;
 		INSERT_WORDS(x,i0&0x80000000,0);	/* return +-0 */
 		return x;
 	    } else {
-	        INSERT_WORDS(*iptr,i0,i1&(~i));
+		INSERT_WORDS(*iptr,i0,i1&(~i));
 		return x - *iptr;
 	    }
 	}
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