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-rw-r--r--libquadmath/math/scalblnq.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/libquadmath/math/scalblnq.c b/libquadmath/math/scalblnq.c
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+/* s_scalblnl.c -- long double version of s_scalbn.c.
+ * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
+ */
+
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+#include "quadmath-imp.h"
+
+static const __float128
+two114 = 2.0769187434139310514121985316880384E+34Q, /* 0x4071000000000000, 0 */
+twom114 = 4.8148248609680896326399448564623183E-35Q, /* 0x3F8D000000000000, 0 */
+huge = 1.0E+4900Q,
+tiny = 1.0E-4900Q;
+
+__float128
+scalblnq (__float128 x, long int n)
+{
+ int64_t k,hx,lx;
+ GET_FLT128_WORDS64(hx,lx,x);
+ k = (hx>>48)&0x7fff; /* extract exponent */
+ if (k==0) { /* 0 or subnormal x */
+ if ((lx|(hx&0x7fffffffffffffffULL))==0) return x; /* +-0 */
+ x *= two114;
+ GET_FLT128_MSW64(hx,x);
+ k = ((hx>>48)&0x7fff) - 114;
+ }
+ if (k==0x7fff) return x+x; /* NaN or Inf */
+ k = k+n;
+ if (n> 50000 || k > 0x7ffe)
+ return huge*copysignq(huge,x); /* overflow */
+ if (n< -50000) return tiny*copysignq(tiny,x); /*underflow*/
+ if (k > 0) /* normal result */
+ {SET_FLT128_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48)); return x;}
+ if (k <= -114)
+ return tiny*copysignq(tiny,x); /*underflow*/
+ k += 114; /* subnormal result */
+ SET_FLT128_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48));
+ return x*twom114;
+}