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Diffstat (limited to 'gnulib/tests/test-ceil2.c')
| m--------- | gnulib | 0 | ||||
| -rw-r--r-- | gnulib/tests/test-ceil2.c | 167 |
2 files changed, 167 insertions, 0 deletions
diff --git a/gnulib b/gnulib deleted file mode 160000 -Subproject 443bc5ffcf7429e557f4a371b0661abe98ddbc1 diff --git a/gnulib/tests/test-ceil2.c b/gnulib/tests/test-ceil2.c new file mode 100644 index 0000000..3cc6767 --- /dev/null +++ b/gnulib/tests/test-ceil2.c @@ -0,0 +1,167 @@ +/* Test of rounding towards positive infinity. + Copyright (C) 2007-2011 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2007. */ + +/* When this test fails on some platform, build it together with the gnulib + module 'fprintf-posix' for optimal debugging output. */ + +#include <config.h> + +#include <math.h> + +#include <float.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> + +#include "isnand-nolibm.h" +#include "minus-zero.h" +#include "macros.h" + + +/* The reference implementation, taken from lib/ceil.c. */ + +#define DOUBLE double +#define MANT_DIG DBL_MANT_DIG +#define L_(literal) literal + +/* -0.0. See minus-zero.h. */ +#define MINUS_ZERO minus_zerod + +/* 2^(MANT_DIG-1). */ +static const DOUBLE TWO_MANT_DIG = + /* Assume MANT_DIG <= 5 * 31. + Use the identity + n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */ + (DOUBLE) (1U << ((MANT_DIG - 1) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5)); + +DOUBLE +ceil_reference (DOUBLE x) +{ + /* The use of 'volatile' guarantees that excess precision bits are dropped + at each addition step and before the following comparison at the caller's + site. It is necessary on x86 systems where double-floats are not IEEE + compliant by default, to avoid that the results become platform and compiler + option dependent. 'volatile' is a portable alternative to gcc's + -ffloat-store option. */ + volatile DOUBLE y = x; + volatile DOUBLE z = y; + + if (z > L_(0.0)) + { + /* Work around ICC's desire to optimize denormal floats to 0. */ + if (z < DBL_MIN) + return L_(1.0); + /* Avoid rounding errors for values near 2^k, where k >= MANT_DIG-1. */ + if (z < TWO_MANT_DIG) + { + /* Round to the next integer (nearest or up or down, doesn't matter). */ + z += TWO_MANT_DIG; + z -= TWO_MANT_DIG; + /* Enforce rounding up. */ + if (z < y) + z += L_(1.0); + } + } + else if (z < L_(0.0)) + { + /* For -1 < x < 0, return -0.0 regardless of the current rounding + mode. */ + if (z > L_(-1.0)) + z = MINUS_ZERO; + /* Avoid rounding errors for values near -2^k, where k >= MANT_DIG-1. */ + else if (z > - TWO_MANT_DIG) + { + /* Round to the next integer (nearest or up or down, doesn't matter). */ + z -= TWO_MANT_DIG; + z += TWO_MANT_DIG; + /* Enforce rounding up. */ + if (z < y) + z += L_(1.0); + } + } + return z; +} + + +/* Test for equality. */ +static int +equal (DOUBLE x, DOUBLE y) +{ + return (isnand (x) ? isnand (y) : x == y); +} + +/* Test whether the result for a given argument is correct. */ +static bool +correct_result_p (DOUBLE x, DOUBLE result) +{ + return + (x > 0 && x <= 1 ? result == L_(1.0) : + x + 1 > x ? result >= x && result <= x + 1 && result - x < 1 : + equal (result, x)); +} + +/* Test the function for a given argument. */ +static int +check (double x) +{ + /* If the reference implementation is incorrect, bail out immediately. */ + double reference = ceil_reference (x); + ASSERT (correct_result_p (x, reference)); + /* If the actual implementation is wrong, return an error code. */ + { + double result = ceil (x); + if (correct_result_p (x, result)) + return 0; + else + { +#if GNULIB_TEST_FPRINTF_POSIX + fprintf (stderr, "ceil %g(%a) = %g(%a) or %g(%a)?\n", + x, x, reference, reference, result, result); +#endif + return 1; + } + } +} + +#define NUM_HIGHBITS 12 +#define NUM_LOWBITS 4 + +int +main () +{ + unsigned int highbits; + unsigned int lowbits; + int error = 0; + for (highbits = 0; highbits < (1 << NUM_HIGHBITS); highbits++) + for (lowbits = 0; lowbits < (1 << NUM_LOWBITS); lowbits++) + { + /* Combine highbits and lowbits into a floating-point number, + sign-extending the lowbits to 64-NUM_HIGHBITS bits. */ + union { double f; uint64_t i; } janus; + janus.i = ((uint64_t) highbits << (64 - NUM_HIGHBITS)) + | ((uint64_t) ((int64_t) ((uint64_t) lowbits << (64 - NUM_LOWBITS)) + >> (64 - NUM_LOWBITS - NUM_HIGHBITS)) + >> NUM_HIGHBITS); + error |= check (janus.f); + } + return (error ? 1 : 0); +} |