The libm-test math test suite tests a number of function points of
math functions in the GNU C library. The following sections contain a
-brief overview. Please note that the test drivers and the Perl script
-"gen-libm-test.pl" have some options. A full list of options is
-available with --help (for the test drivers) and -h for
-"gen-libm-test.pl".
+brief overview. Please note that the test drivers and the Python
+script "gen-libm-test.py" have some options. A full list of options
+is available with --help (for the test drivers) and -h for
+"gen-libm-test.py".
What is tested?
Files that are part of libm-test
================================
-The main file is "libm-test.inc". It is platform and floating point
-format independent. The file must be preprocessed by the Perl script
-"gen-libm-test.pl". The results are "libm-test.c" and a file
-"libm-test-ulps.h" with platform specific deltas.
-
-The test drivers test-double.c, test-float.c, test-ldouble.c test the
-normal double, float and long double implementation of libm. The test
-drivers with an i in it (test-idouble.c, test-ifloat.c,
-test-ildoubl.c) test the corresponding inline functions (where
-available - otherwise they also test the real functions in libm).
-
-"gen-libm-test.pl" needs a platform specific files with ULPs (Units of
-Last Precision). The file is called "libm-test-ulps" and lives in
-platform specific sysdep directory.
+The main files are "libm-test-<func>.inc". They are independent of
+the target platform and the specific real floating type and format and
+contain placeholder test "templates" for math functions defined in
+libm. These files, along with generated files named
+"auto-libm-test-out-<func>", are preprocessed by the Python script
+"gen-libm-test.py" to expand the templates and produce a set of test
+cases for each math function that are specific to the target platform
+but still independent of the real floating type. The results of the
+processing are "libm-test-<func>.c" and a file "libm-test-ulps.h" with
+platform specific deltas by which the actual math function results may
+deviate from the expected results and still be considered correct.
+
+The test drivers "test-double-<func>.c", "test-float-<func>.c", and
+"test-ldouble-<func>.c", generated by the Makefile, test the normal
+double, float and long double implementation of libm. The test
+drivers with an 'i' in their name ("test-idouble-<func>.c",
+"test-ifloat-<func>.c", and "test-ildoubl-<func>.c") test the
+corresponding inline functions (where available - otherwise they also
+test the real functions in libm). Each driver selects the desired
+real floating type to exercise the math functions to test with (float,
+double, or long double) by defining a small set of macros just before
+including the generic "libm-test.c" file. Each driver also either
+defines or undefines the __NO_MATH_INLINES macro just before including
+"libm-test-<func>.c" to select either the real or inline functions,
+respectively. Each driver is compiled into a single executable test
+program with the corresponding name.
+
+As mentioned above, the "gen-libm-test.py" script looks for a file
+named "libm-test-ulps" in the platform specific sysdep directory (or
+its fpu or nofpu subdirectory) and for each variant (real floating
+type and rounding mode) of every tested function reads from it the
+maximum difference expressed as Units of Least Precision (ULP) the
+actual result of the function may deviate from the expected result
+before it's considered incorrect.
+
+The "auto-libm-test-out-<func>" files contain sets of test cases to
+exercise, the conditions under which to exercise each, and the
+expected results. The files are generated by the
+"gen-auto-libm-tests" program from the "auto-libm-test-in" file. See
+the comments in gen-auto-libm-tests.c for details about the content
+and format of the -in and -out files.
How can I generate "libm-test-ulps"?
====================================
previously calculated ULPs, and running with the newly built dynamic
loader and math library (assumes you didn't install your build). Now
generate the ULPs for all other formats, the tests will be appending the
-data to the "ULPs" file. As final step run "gen-libm-test.pl" with the
+data to the "ULPs" file. As final step run "gen-libm-test.py" with the
file as input and ask to generate a pretty printed output in the file
"NewUlps":
- gen-libm-test.pl -u ULPs -n
+ gen-libm-test.py -u ULPs -n NewUlps
Copy "NewUlps" to "libm-test-ulps" in the appropriate machine sysdep
directory.
Note that the test drivers have an option "-u" to output an unsorted
list of all epsilons that the functions have. The output can be read
in directly but it's better to pretty print it first.
-"gen-libm-test.pl" has an option to generate a pretty-printed and
+"gen-libm-test.py" has an option to generate a pretty-printed and
sorted new ULPs file from the output of the test drivers.
Contents of libm-test-ulps
The keywords are float, ifloat, double, idouble, ldouble and ildouble
(the prefix i stands for inline).
-Adding tests to libm-test.inc
-=============================
+Adding tests to libm-test-<func>.inc
+====================================
The tests are evaluated by a set of special test macros. The macros
start with "TEST_" followed by a specification the input values, an
The accepted parameter types are:
- "f" for FLOAT
+- "j" for long double.
+- "a" for ARG_FLOAT, the argument type for narrowing functions.
- "b" for boolean - just tests if the output parameter evaluates to 0
or 1 (only for output).
- "c" for complex. This parameter needs two values, first the real,
- "i" for int.
- "l" for long int.
- "L" for long long int.
+- "u" for unsigned int.
+- "M" for intmax_t.
+- "U" for uintmax_t.
+- "p" for an argument (described in the previous character) passed
+ through a pointer rather than directly.
- "F" for the address of a FLOAT (only as input parameter)
- "I" for the address of an int (only as input parameter)
+- "1" for an additional output (either output through a pointer passed
+ as an argument, or to a global variable such as signgam).
+
+How to read the test output
+===========================
+
+Running each test on its own at the default level of verbosity will
+print on stdout a line describing the implementation of math functions
+exercised by the test (float, double, or long double), along with
+whether the inline set has been selected, regardless of whether or
+not any inline functions actually exist. This is then followed by
+the details of test failures (if any). The output concludes by
+a summary listing the number of test cases exercised and the number
+of test failures uncovered.
+
+For each test failure (and for each test case at higher levels of
+verbosity), the output contains the name of the function under test
+and its arguments or conditions that triggered the failure. Note
+that the name of the function in the output need not correspond
+exactly to the name of the math function actually invoked. For example,
+the output will refer to the "acos" function even if the actual function
+under test is acosf (for the float version) or acosl (for the long
+double version). Also note that the function arguments may be shown
+in either the decimal or the hexadecimal floating point format which
+may or may not correspond to the format used in the auto-libm-test-in
+file. Besides the name of the function, for each test failure the
+output contains the actual and expected results and the difference
+between the two, printed in both the decimal and hexadecimal
+floating point format, and the ULP and maximum ULP for the test
+case.
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