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Diffstat (limited to 'math/test-reduce.c')
| -rw-r--r-- | math/test-reduce.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/math/test-reduce.c b/math/test-reduce.c new file mode 100644 index 0000000000..5149ead341 --- /dev/null +++ b/math/test-reduce.c @@ -0,0 +1,207 @@ +/* Copyright (C) 1997 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Geoffrey Keating <Geoff.Keating@anu.edu.au>, 1997. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +/* This is a generic program for comparing two precisions of a one-input + mathematical function. It is amazingly good at detecting when GCC + folds constants improperly. */ + +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif +#include <math.h> +#include <ieee754.h> +#include <fenv.h> +#include <stdio.h> +#include <stdlib.h> +#include <time.h> + +#define TSMALL float +#define RSMALL(rfun) ({ unsigned rnum = (rfun); *(float *) &rnum; }) +#define TBIG double +#define XDIFF (24) +#define REDUCE(x) \ + ({ union ieee754_float u = { x }; u.ieee.exponent = 0x80; x = u.f; }) +#define ABS(x) fabs(x) + +#define string_0(x) #x +#define string_1(x) string_0(x) +#define TBIG_NAME string_1(TBIG) +#define TSMALL_NAME string_1(TSMALL) + +#define R_NEAREST 1 +#define R_ZERO 2 +#define R_UP 4 +#define R_DOWN 8 +#define R_ALL (R_NEAREST|R_ZERO|R_UP|R_DOWN) +static fenv_t rmodes[4]; +static const char * const rmnames[4] = +{ "near","zero","+Inf","-Inf" }; + +static int quiet = 0; + +#ifdef FE_ALL_INVALID +static const int invalid_exceptions = (FE_ALL_INVALID + | FE_INVALID | FE_DIVBYZERO); +#else +static const int invalid_exceptions = (FE_INVALID | FE_DIVBYZERO); +#endif + +static int +checkit (char *fname, + TSMALL (*fsmall) (TSMALL), TBIG (*fbig) (TBIG), + unsigned smalltries, unsigned largetries) +{ + unsigned int i, nerrors = 0, nwarn; + + int tryone (TSMALL fval) + { + int rmode; + int excepts, exceptsb; + TSMALL fres; + TBIG fvalb, fresb, diff; + char warn; + + fvalb = (TBIG) fval; + + for (rmode = 0; rmode < 4; ++rmode) + { + fesetenv (rmodes + rmode); + fres = fsmall (fval); + excepts = fetestexcept (invalid_exceptions); + fesetenv (rmodes + rmode); + fresb = fbig (fvalb); + exceptsb = fetestexcept (invalid_exceptions); + + if (excepts != exceptsb) + { + unsigned char *fvp = (unsigned char *) &fval; + size_t j; + + printf ("%s(", fname); + for (j = 0; j < sizeof (TSMALL); j++) + printf ("%02x", fvp[j]); + printf ("),%s: exceptions %s: %08x, %s: %08x\n", + rmnames[rmode], + TBIG_NAME, exceptsb, TSMALL_NAME, excepts); + if (++nerrors > 10) + return 1; + } + + diff = ABS (fres - (TSMALL) fresb); + if (fres == (TSMALL) fresb + || isnan (fres) && isnan (fresb) + || logb (fresb) - logb (diff) < XDIFF - 1) + continue; + + if (logb (fresb) - logb (diff) < XDIFF) + { + if (++nwarn > 10 || quiet) + continue; + warn = 'w'; + } + else + { + if (++nerrors > 10) + return 1; + warn = 'e'; + } + + { + TSMALL fresbs = (TSMALL) fresb; + unsigned char *fvp = (unsigned char *) &fval; + unsigned char *frp = (unsigned char *) &fres; + unsigned char *frpb = (unsigned char *) &fresb; + unsigned char *frpbs = (unsigned char *) &fresbs; + size_t j; + + printf ("%s(",fname); + for (j = 0; j < sizeof (TSMALL); ++j) + printf ("%02x", fvp[j]); + printf ("),%s: %s ", rmnames[rmode], TBIG_NAME); + for (j = 0; j < sizeof (TBIG); ++j) + printf ("%02x", frpb[j]); + printf (" ("); + for (j = 0; j < sizeof (TSMALL); ++j) + printf ("%02x", frpbs[j]); + printf ("), %s ", TSMALL_NAME); + for (j = 0; j < sizeof (TSMALL); ++j) + printf ("%02x", frp[j]); + printf (" %c\n", warn); + } + } + return 0; + } + + nwarn = 0; + for (i = 0; i < smalltries; i++) + { + TSMALL fval; + + fval = RSMALL (rand () ^ rand () << 16); + REDUCE (fval); + if (tryone (fval)) + break; + } + + printf ("%s-small: %d errors, %d (%0.2f%%) inaccuracies\n", + fname, nerrors, nwarn, + nwarn * 0.25 / ((double) smalltries)); + + nwarn = 0; + for (i = 0; i < largetries; ++i) + { + TSMALL fval; + + fval = RSMALL (rand () ^ rand () << 16); + if (tryone (fval)) + break; + } + + printf ("%s-large: %d errors, %d (%0.2f%%) inaccuracies\n", + fname, nerrors, nwarn, + nwarn * 0.25 / ((double) largetries)); + return nerrors == 0; +} + +int +main (void) +{ + int r; + + _LIB_VERSION = _IEEE_; + + /* Set up environments for rounding modes. */ + fesetenv (FE_DFL_ENV); + fesetround (FE_TONEAREST); + fegetenv (rmodes + 0); + fesetround (FE_TOWARDSZERO); + fegetenv (rmodes + 1); + fesetround (FE_UPWARD); + fegetenv (rmodes + 2); + fesetround (FE_DOWNWARD); + fegetenv (rmodes + 3); + + /* Seed the RNG. */ + srand (time (0)); + + /* Do it. */ + r = checkit ("exp2", exp2f, exp2, 1 << 20, 1 << 15); + r &= checkit ("exp", expf, exp, 1 << 20, 1 << 15); + return r ? 0 : 1; +} |