Re: [Iverilog-devel] Integrating va_math into git

[Stephen W. <st...@ic...>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Cary R. wrote:
| --- On Wed, 4/30/08, Stephen Williams <st...@ic...> wrote:
|
|> Unsure about the examples in the bundle, but I put the test
|> program
|> in the ivtest suite. There are a few differences that we
|> may want
|> to wrinkle out so that the test can give an accurate
|> pass/fail.
|
| OK on the examples. I probably should put together something for the
wiki "Analog modeling using Icarus Verilog".

Sounds exactly perfect.

| I'm not so certain test_va_math should even be in the test suite.
These tests explicitly push into the obscure corners of the native math
library. Because of this you can get different results depending on the
underlying math library. These differences are usually not significant
and when they are they usually do not indicate a problem in the va_math
library. I always meant for these tests to be subjective not absolute.
|
| The main difference I know about is taking the tan of pi/2 or -pi/2.
My two system would match the pi/2 tests if we truncated the result to
four digits, but MinGW has many differences (inf/nan representation and
some other corner case deviations from the FP standard).
|
| FYI the tan tests for my two machines give 1.63318e+16 (RHEL 4) and
1.63312e+16 (cygwin). So when you consider rounding 1.633e+16 is the
common result. Making the two pi/2 test use %.4g instead of %g should
work for me (remember for %g the number after the . is the number of
significant digits not the number of digits).

I have found that on my mac a few of the numbers came out different
only at the least significant bits. I also found, though, that one
of the 0.0 values turns out to be -0.0. I don't remember which that
is, as the mac is currently with the wife at school. I think we can
tweak the test and the gold file to turn it into a practical test
suite test. It's already in ivtest CVS.


- --
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.4-svn0 (GNU/Linux)
Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org

iD8DBQFIGKv9rPt1Sc2b3ikRAl3ZAKC2JKq1b+Jjh2PzcFU7ELgWSx78zwCgsVCT
OEOc84xUmqW6B+cfXDqVUGE=
=CpnM
-----END PGP SIGNATURE-----