summaryrefslogtreecommitdiff
path: root/REORG.TODO/sysdeps/ieee754/ldbl-96/s_scalblnl.c
diff options
context:
space:
mode:
Diffstat (limited to 'REORG.TODO/sysdeps/ieee754/ldbl-96/s_scalblnl.c')
-rw-r--r--REORG.TODO/sysdeps/ieee754/ldbl-96/s_scalblnl.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/ieee754/ldbl-96/s_scalblnl.c b/REORG.TODO/sysdeps/ieee754/ldbl-96/s_scalblnl.c
new file mode 100644
index 0000000000..457e999c6c
--- /dev/null
+++ b/REORG.TODO/sysdeps/ieee754/ldbl-96/s_scalblnl.c
@@ -0,0 +1,60 @@
+/* s_scalbnl.c -- long double version of s_scalbn.c.
+ * Conversion to long double by Ulrich Drepper,
+ * Cygnus Support, drepper@cygnus.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.
+ * ====================================================
+ */
+
+/*
+ * scalbnl (long double x, int n)
+ * scalbnl(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>
+
+static const long double
+two63 = 0x1p63L,
+twom64 = 0x1p-64L,
+huge = 1.0e+4900L,
+tiny = 1.0e-4900L;
+
+long double
+__scalblnl (long double x, long int n)
+{
+ int32_t k,es,hx,lx;
+ GET_LDOUBLE_WORDS(es,hx,lx,x);
+ k = es&0x7fff; /* extract exponent */
+ if (__builtin_expect(k==0, 0)) { /* 0 or subnormal x */
+ if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
+ x *= two63;
+ GET_LDOUBLE_EXP(es,x);
+ k = (es&0x7fff) - 63;
+ }
+ if (__builtin_expect(k==0x7fff, 0)) return x+x; /* NaN or Inf */
+ if (__builtin_expect(n< -50000, 0))
+ return tiny*__copysignl(tiny,x);
+ if (__builtin_expect(n> 50000 || k+n > 0x7ffe, 0))
+ return huge*__copysignl(huge,x); /* overflow */
+ /* Now k and n are bounded we know that k = k+n does not
+ overflow. */
+ k = k+n;
+ if (__builtin_expect(k > 0, 1)) /* normal result */
+ {SET_LDOUBLE_EXP(x,(es&0x8000)|k); return x;}
+ if (k <= -64)
+ return tiny*__copysignl(tiny,x); /*underflow*/
+ k += 64; /* subnormal result */
+ SET_LDOUBLE_EXP(x,(es&0x8000)|k);
+ return x*twom64;
+}