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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 /gcc/testsuite/gcc.c-torture/execute/cbrt.c
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Diffstat (limited to 'gcc/testsuite/gcc.c-torture/execute/cbrt.c')
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diff --git a/gcc/testsuite/gcc.c-torture/execute/cbrt.c b/gcc/testsuite/gcc.c-torture/execute/cbrt.c
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index 000000000..8659cc7a7
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+++ b/gcc/testsuite/gcc.c-torture/execute/cbrt.c
@@ -0,0 +1,92 @@
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+*/
+
+#ifndef __vax__
+static const unsigned long
+ B1 = 715094163, /* B1 = (682-0.03306235651)*2**20 */
+ B2 = 696219795; /* B2 = (664-0.03306235651)*2**20 */
+
+static const double
+ C = 5.42857142857142815906e-01, /* 19/35 = 0x3FE15F15, 0xF15F15F1 */
+ D = -7.05306122448979611050e-01, /* -864/1225 = 0xBFE691DE, 0x2532C834 */
+ E = 1.41428571428571436819e+00, /* 99/70 = 0x3FF6A0EA, 0x0EA0EA0F */
+ F = 1.60714285714285720630e+00, /* 45/28 = 0x3FF9B6DB, 0x6DB6DB6E */
+ G = 3.57142857142857150787e-01; /* 5/14 = 0x3FD6DB6D, 0xB6DB6DB7 */
+
+double
+cbrtl (double x)
+{
+ long hx;
+ double r,s,w;
+ double lt;
+ unsigned sign;
+ typedef unsigned unsigned32 __attribute__((mode(SI)));
+ union {
+ double t;
+ unsigned32 pt[2];
+ } ut, ux;
+ int n0;
+
+ ut.t = 1.0;
+ n0 = (ut.pt[0] == 0);
+
+ ut.t = 0.0;
+ ux.t = x;
+
+ hx = ux.pt[n0]; /* high word of x */
+ sign=hx&0x80000000; /* sign= sign(x) */
+ hx ^=sign;
+ if(hx>=0x7ff00000) return(x+x); /* cbrt(NaN,INF) is itself */
+ if((hx| ux.pt[1-n0])==0)
+ return(ux.t); /* cbrt(0) is itself */
+
+ ux.pt[n0] = hx;
+ /* rough cbrt to 5 bits */
+ if(hx<0x00100000) /* subnormal number */
+ {ut.pt[n0]=0x43500000; /* set t= 2**54 */
+ ut.t*=x; ut.pt[n0]=ut.pt[n0]/3+B2;
+ }
+ else
+ ut.pt[n0]=hx/3+B1;
+
+ /* new cbrt to 23 bits, may be implemented in single precision */
+ r=ut.t*ut.t/ux.t;
+ s=C+r*ut.t;
+ ut.t*=G+F/(s+E+D/s);
+
+ /* chopped to 20 bits and make it larger than cbrt(x) */
+ ut.pt[1-n0]=0; ut.pt[n0]+=0x00000001;
+
+ /* one step newton iteration to 53 bits with error less than 0.667 ulps */
+ s=ut.t*ut.t; /* t*t is exact */
+ r=ux.t/s;
+ w=ut.t+ut.t;
+ r=(r-ut.t)/(w+r); /* r-s is exact */
+ ut.t=ut.t+ut.t*r;
+
+ /* restore the sign bit */
+ ut.pt[n0] |= sign;
+
+ lt = ut.t;
+ lt -= (lt - (x/(lt*lt))) * 0.333333333333333333333;
+ return lt;
+}
+
+main ()
+{
+ if ((int) (cbrtl (27.0) + 0.5) != 3)
+ abort ();
+
+ exit (0);
+}
+#else
+main () { exit (0); }
+#endif