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2004-03-24 Jakub Jelinek <jakub@redhat.com> * stdlib/strtod_l.c (INTERNAL (__STRTOF)): Clear the rest of retval, not just one limb if RETURN_LIMB_SIZE > 2. Fix shifting up if RETURN_LIMB_SIZE > 2. * stdio-common/printf_fp.c (__printf_fp): For IEEE quad long double on 32-bit architectures reserve 8 limbs instead of 4.
108 lines
4.1 KiB
Plaintext
108 lines
4.1 KiB
Plaintext
README for libm-test math test suite
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====================================
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The libm-test math test suite tests a number of function points of
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math functions in the GNU C library. The following sections contain a
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brief overview. Please note that the test drivers and the Perl script
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"gen-libm-test.pl" have some options. A full list of options is
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available with --help (for the test drivers) and -h for
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"gen-libm-test.pl".
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What is tested?
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===============
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The tests just evaluate the functions at specified points and compare
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the results with precomputed values and the requirements of the ISO
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C99 standard.
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Besides testing the special values mandated by IEEE 754 (infinities,
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NaNs and minus zero), some more or less random values are tested.
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Files that are part of libm-test
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================================
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The main file is "libm-test.inc". It is platform and floating point
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format independent. The file must be preprocessed by the Perl script
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"gen-libm-test.pl". The results are "libm-test.c" and a file
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"libm-test-ulps.h" with platform specific deltas.
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The test drivers test-double.c, test-float.c, test-ldouble.c test the
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normal double, float and long double implementation of libm. The test
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drivers with an i in it (test-idouble.c, test-ifloat.c,
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test-ildoubl.c) test the corresponding inline functions (where
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available - otherwise they also test the real functions in libm).
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"gen-libm-test.pl" needs a platform specific files with ULPs (Units of
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Last Precision). The file is called "libm-test-ulps" and lives in
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platform specific sysdep directory.
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How can I generate "libm-test-ulps"?
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====================================
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The test drivers have an option "-u" to output an unsorted list of all
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epsilons that the functions have. The output can be read in directly
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but it's better to pretty print it first. "gen-libm-test.pl" has an option
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to generate a pretty-printed and sorted new ULPs file from the output
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of the test drivers.
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To generate a new "libm-test-ulps" file, first remove "ULPs" file in the
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current directory, then you can execute for example:
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test-double -u --ignore-max-ulp=yes
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This generates a file "ULPs" with all double ULPs in it, ignoring any
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previous calculated ULPs.
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Now generate the ULPs for all other formats, the tests will be appending
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the data to the "ULPs" file. As final step run "gen-libm-test.pl" with the
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file as input and ask to generate a pretty printed output in the file "NewUlps":
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gen-libm-test.pl -u ULPs -n
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Now you can rename "NewUlps" to "libm-test-ulps" and move it into
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sysdeps.
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Contents of libm-test-ulps
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==========================
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Since libm-test-ulps can be generated automatically, just a few
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notes. The file contains lines for single tests, like:
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Test "cos (pi/2) == 0":
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float: 1
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and lines for maximal errors of single functions, like:
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Function "yn":
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idouble: 6.0000
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The keywords are float, ifloat, double, idouble, ldouble and ildouble
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(the prefix i stands for inline). You can also specify known
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failures, e.g.:
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Test "cos (pi/2) == 0":
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float: 1
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float: fail
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Adding tests to libm-test.inc
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=============================
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The tests are evaluated by a set of special test macros. The macros
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start with "TEST_" followed by a specification the input values, an
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underscore and a specification of the output values. As an example,
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the test macro for a function with input of type FLOAT (FLOAT is
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either float, double, long double) and output of type FLOAT is
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"TEST_f_f". The macro's parameter are the name of the function, the
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input parameter, output parameter and optionally one exception
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parameter.
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The accepted parameter types are:
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- "f" for FLOAT
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- "b" for boolean - just tests if the output parameter evaluates to 0
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or 1 (only for output).
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- "c" for complex. This parameter needs two values, first the real,
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then the imaginary part.
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- "i" for int.
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- "l" for long int.
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- "L" for long long int.
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- "F" for the address of a FLOAT (only as input parameter)
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- "I" for the address of an int (only as input parameter)
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Some functions need special handling. For example gamma sets the
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global variable signgam and frexp takes an argument to &int. This
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special treatment is coded in "gen-libm-test.pl" and used while
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parsing "libm-test.inc".
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