[ieeefp-tests-devel] Tests for log of negative numbers?

[Raymond Toy]

In the test suite, there are quite a few tests for log of negative
numbers.  I was in the process of converting the generated tests to
return +quiet-<float>-nan-mask+ for :uo tests.  However, this caused a
huge increase in the number of failures.

One of them is SINGLE-LOG-VALUE.41:

Form: (PROGN
        "logs n uo v 80800000 0"
        (IEEEFP-TESTS::SET-UP-FPCW-STATE :NEAREST)
        (LET ((IEEEFP-TESTS::RESULT
               (LOG
                (IEEE754:MAKE-SINGLE-FLOAT
                 IEEEFP-TESTS::+LEAST-NEGATIVE-NORMALIZED-SINGLE-FLOAT+))))
          (IF (COMPLEXP IEEEFP-TESTS::RESULT)
              T
              (LET ((IEEEFP-TESTS::RESULT-BITS
                     (IEEE754:SINGLE-FLOAT-BITS IEEEFP-TESTS::RESULT)))
                (= (LOGAND IEEEFP-TESTS::RESULT-BITS
                         IEEEFP-TESTS::+QUIET-SINGLE-FLOAT-NAN-MASK+)
                    IEEEFP-TESTS::+QUIET-SINGLE-FLOAT-NAN-MASK+)))))
Expected value: T


The tests expects (log <negative) to be a NaN, but we were passing the
test because we returned T because we got a complex result.  

Is this the desired answer?  In terms of the test, I think we should
fail the test.  When I modify the test to return the logand result and
an expected answer of quiet-single-float-nan-mask, we do fail, of
course. 

Another interesting test is single-log-value.54.  CMUCL says (log
<negative quiet NaN>) is #c(<quiet nan> pi).  That's seems debatable.

Anyway, I wanted your opinion on whether Lisp should fail
single-log-value.41. 

Ray