Add 64-bit optimized scalbln.

diff --git a/ChangeLog b/ChangeLog
index e7ce260..171e0c2 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2009-08-25  Ulrich Drepper  <drepper@redhat.com>
 
+       * sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c: New file.
+
        * sysdeps/x86_64/fpu/s_signbit.S: New file.
        * sysdeps/x86_64/fpu/s_signbitf.S: New file.
 

diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c
new file mode 100644 (file)
index 0000000..25b283f
--- /dev/null
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c
@@ -0,0 +1,68 @@
+/* @(#)s_scalbn.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.
+ * ====================================================
+ */
+
+/*
+ * scalbn (double x, int n)
+ * scalbn(x,n) returns x* 2**n  computed by  exponent
+ * manipulation rather than by actually performing an
+ * exponentiation or a multiplication.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const double
+#else
+static double
+#endif
+two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
+twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
+huge   = 1.0e+300,
+tiny   = 1.0e-300;
+
+#ifdef __STDC__
+       double __scalbln (double x, long int n)
+#else
+       double __scalbln (x,n)
+       double x; long int n;
+#endif
+{
+       int64_t ix;
+       int64_t k;
+       EXTRACT_WORDS64(ix,x);
+       k = (ix >> 52) & 0x7ff;                 /* extract exponent */
+       if (k==0) {                             /* 0 or subnormal x */
+           if ((ix & UINT64_C(0xfffffffffffff))==0) return x; /* +-0 */
+           x *= two54;
+           EXTRACT_WORDS64(ix,x);
+           k = ((ix >> 52) & 0x7ff) - 54;
+           }
+       if (k==0x7ff) return x+x;               /* NaN or Inf */
+       k = k+n;
+       if (n> 50000 || k >  0x7fe)
+         return huge*__copysign(huge,x); /* overflow  */
+       if (n< -50000) return tiny*__copysign(tiny,x); /*underflow*/
+       if (k > 0)                              /* normal result */
+           {INSERT_WORDS64(x,(ix&UINT64_C(0x800fffffffffffff))|(k<<52));
+             return x;}
+       if (k <= -54)
+         return tiny*__copysign(tiny,x);       /*underflow*/
+       k += 54;                                /* subnormal result */
+       INSERT_WORDS64(x,(ix&INT64_C(0x800fffffffffffff))|(k<<52));
+       return x*twom54;
+}
+weak_alias (__scalbln, scalbln)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__scalbln, __scalblnl)
+weak_alias (__scalbln, scalblnl)
+#endif