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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libquadmath/math/nearbyintq.c
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Diffstat (limited to 'libquadmath/math/nearbyintq.c')
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diff --git a/libquadmath/math/nearbyintq.c b/libquadmath/math/nearbyintq.c
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+/* nearbyintq.c -- __float128 version of s_nearbyint.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.
+ * ====================================================
+ */
+
+/*
+ * nearbyintq(x)
+ * Return x rounded to integral value according to the prevailing
+ * rounding mode.
+ * Method:
+ * Using floating addition.
+ * Exception:
+ * Inexact flag raised if x not equal to rintq(x).
+ */
+
+#include "quadmath-imp.h"
+#ifdef HAVE_FENV_H
+# include <fenv.h>
+# if defined HAVE_FEHOLDEXCEPT && defined HAVE_FESETENV
+# define USE_FENV_H
+# endif
+#endif
+
+static const __float128
+TWO112[2]={
+ 5.19229685853482762853049632922009600E+33Q, /* 0x406F000000000000, 0 */
+ -5.19229685853482762853049632922009600E+33Q /* 0xC06F000000000000, 0 */
+};
+
+__float128
+nearbyintq(__float128 x)
+{
+#ifdef USE_FENV_H
+ fenv_t env;
+#endif
+ int64_t i0,j0,sx;
+ uint64_t i,i1;
+ __float128 w,t;
+ GET_FLT128_WORDS64(i0,i1,x);
+ sx = (((uint64_t)i0)>>63);
+ j0 = ((i0>>48)&0x7fff)-0x3fff;
+ if(j0<48) {
+ if(j0<0) {
+ if(((i0&0x7fffffffffffffffLL)|i1)==0) return x;
+ i1 |= (i0&0x0000ffffffffffffLL);
+ i0 &= 0xffffe00000000000ULL;
+ i0 |= ((i1|-i1)>>16)&0x0000800000000000LL;
+ SET_FLT128_MSW64(x,i0);
+#ifdef USE_FENV_H
+ feholdexcept (&env);
+#endif
+ w = TWO112[sx]+x;
+ t = w-TWO112[sx];
+#ifdef USE_FENV_H
+ fesetenv (&env);
+#endif
+ GET_FLT128_MSW64(i0,t);
+ SET_FLT128_MSW64(t,(i0&0x7fffffffffffffffLL)|(sx<<63));
+ return t;
+ } else {
+ i = (0x0000ffffffffffffLL)>>j0;
+ if(((i0&i)|i1)==0) return x; /* x is integral */
+ i>>=1;
+ if(((i0&i)|i1)!=0) {
+ if(j0==47) i1 = 0x4000000000000000ULL; else
+ i0 = (i0&(~i))|((0x0000200000000000LL)>>j0);
+ }
+ }
+ } else if (j0>111) {
+ if(j0==0x4000) return x+x; /* inf or NaN */
+ else return x; /* x is integral */
+ } else {
+ i = -1ULL>>(j0-48);
+ if((i1&i)==0) return x; /* x is integral */
+ i>>=1;
+ if((i1&i)!=0) i1 = (i1&(~i))|((0x4000000000000000LL)>>(j0-48));
+ }
+ SET_FLT128_WORDS64(x,i0,i1);
+#ifdef USE_FENV_H
+ feholdexcept (&env);
+#endif
+ w = TWO112[sx]+x;
+ t = w-TWO112[sx];
+#ifdef USE_FENV_H
+ fesetenv (&env);
+#endif
+ return t;
+}