diff --git a/test-suite/standalone/test-round.c b/test-suite/standalone/test-round.c new file mode 100644 index 000000000..3cab0600e --- /dev/null +++ b/test-suite/standalone/test-round.c @@ -0,0 +1,122 @@ +/* Copyright (C) 2004 Free Software Foundation, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include "config.h" + +#include +#include +#include + +#if HAVE_FENV_H +#include +#endif + +#include "libguile.h" + + +#define numberof(x) (sizeof (x) / sizeof ((x)[0])) + +static void +test_scm_round () +{ + /* FE constants are defined only where supported, in particular for + instance some ARM systems have been seen with only a couple of modes */ + static const int modes[] = { + 0, +#ifdef FE_TONEAREST + FE_TONEAREST, +#endif +#ifdef FE_UPWARD + FE_UPWARD, +#endif +#ifdef FE_DOWNWARD + FE_DOWNWARD, +#endif +#ifdef FE_TOWARDZERO + FE_TOWARDZERO, +#endif + }; + + double x, want; + int i; + + for (i = 0; i < numberof (modes); i++) + { + /* First iteration is the default rounding mode, ie. no call to + fesetround. Subsequent iterations are the FE modes from the + table. */ + if (i != 0) + { +#if HAVE_FESETROUND + fesetround (modes[i]); +#endif + } + + assert (scm_round (0.0) == 0.0); + assert (scm_round (1.0) == 1.0); + assert (scm_round (-1.0) == -1.0); + + assert (scm_round (0.5) == 0.0); + assert (scm_round (1.5) == 2.0); + assert (scm_round (-1.5) == -2.0); + assert (scm_round (2.5) == 2.0); + assert (scm_round (-2.5) == -2.0); + assert (scm_round (3.5) == 4.0); + assert (scm_round (-3.5) == -4.0); + + /* 2^(DBL_MANT_DIG-1)-1+0.5 */ + x = ldexp (1.0, DBL_MANT_DIG - 1) - 1.0 + 0.5; + want = ldexp (1.0, DBL_MANT_DIG - 1); + assert (scm_round (x) == want); + + /* -(2^(DBL_MANT_DIG-1)-1+0.5) */ + x = - (ldexp (1.0, DBL_MANT_DIG - 1) - 1.0 + 0.5); + want = - ldexp (1.0, DBL_MANT_DIG - 1); + assert (scm_round (x) == want); + + /* 2^DBL_MANT_DIG-1 + In the past scm_round had incorrectly incremented this value, due + to the way that x+0.5 would round upwards (in the usual default + nearest-even mode on most systems). */ + x = ldexp (1.0, DBL_MANT_DIG) - 1.0; + assert (x == floor (x)); /* should be an integer already */ + assert (scm_round (x) == x); /* scm_round should return it unchanged */ + + /* -(2^DBL_MANT_DIG-1) */ + x = - (ldexp (1.0, DBL_MANT_DIG) - 1.0); + assert (x == floor (x)); /* should be an integer already */ + assert (scm_round (x) == x); /* scm_round should return it unchanged */ + + /* 2^64 */ + x = ldexp (1.0, 64); + assert (scm_round (x) == x); + + /* -2^64 + In the past scm_round had incorrectely gone to the next highest + representable value in FE_UPWARD, due to x+0.5 rounding. */ + x = - ldexp (1.0, 64); + assert (scm_round (x) == x); + } +} + +int +main (int argc, char *argv[]) +{ + scm_init_guile(); + test_scm_round (); + return 0; +}