Re: [Qemu-devel] [Bug 645662] Re: QEMU x87 emulation of trig and other complex ops is only at 64-bit precision, not 80-bit

[Arno Wagner]

To be sure, you can also run my original C test code from
2010. If that produces a bit-identtical result, then this
has indeed been fixed. If there are deviations in the last
digits, then the fingerprinting issues is still there, but
at least Python has stopped complaining.

Regards,
Arno

On Fri, Aug 16, 2019 at 07:47:59 CEST, Thomas Huth wrote:
> The test code from comment #1 now prints out the correct value with QEMU
> v4.1, so I think this has been fixed with the softfloat work that has
> been done within the last year.
> 
> ** Changed in: qemu
>        Status: Confirmed => Fix Released
> 
> -- 
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/645662
> 
> Title:
>   QEMU x87 emulation of trig and other complex ops is only at 64-bit
>   precision, not 80-bit
> 
> Status in QEMU:
>   Fix Released
> 
> Bug description:
>   When doing the regression tests for Python 3.1.2 with Qemu 0.12.5, (Linux 
> version 2.6.26-2-686 (Debian 2.6.26-25lenny1)),
>   gcc (Debian 4.3.2-1.1) 4.3.2, Python compiled from sources within qemu,
>   3 math tests fail, apparently because the floating point unit is buggy. 
> Qmeu was compiled from original sources
>   on Debian Lenny with kernel  2.6.34.6 from kernel.org, gcc  (Debian 
> 4.3.2-1.1) 4.3. 
> 
>   Regression testing errors:
> 
>   test_cmath
>   test test_cmath failed -- Traceback (most recent call last):
>     File "/root/tools/python3/Python-3.1.2/Lib/test/test_cmath.py", line 364, 
> in
>       self.fail(error_message)
>   AssertionError: acos0034: acos(complex(-1.0000000000000002, 0.0))
>   Expected: complex(3.141592653589793, -2.1073424255447014e-08)
>   Received: complex(3.141592653589793, -2.1073424338879928e-08)
>   Received value insufficiently close to expected value.
> 
>   
>   test_float
>   test test_float failed -- Traceback (most recent call last):
>     File "/root/tools/python3/Python-3.1.2/Lib/test/test_float.py", line 479, 
> in
>       self.assertEqual(s, repr(float(s)))
>   AssertionError: '8.72293771110361e+25' != '8.722937711103609e+25'
> 
>   
>   test_math
>   test test_math failed -- multiple errors occurred; run in verbose mode for 
> deta
> 
>   =>
> 
>   runtests.sh -v test_math
> 
>   le01:~/tools/python3/Python-3.1.2# ./runtests.sh -v test_math
>   test_math BAD
>    1 BAD
>    0 GOOD
>    0 SKIPPED
>    1 total
>   le01:~/tools/python3/Python-3.1.2#
> 
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/qemu/+bug/645662/+subscriptions

-- 
Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: address@hidden
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
----
A good decision is based on knowledge and not on numbers. -- Plato

If it's in the news, don't worry about it.  The very definition of 
"news" is "something that hardly ever happens." -- Bruce Schneier

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https://bugs.launchpad.net/bugs/645662

Title:
  QEMU x87 emulation of trig and other complex ops is only at 64-bit
  precision, not 80-bit

Status in QEMU:
  Fix Released

Bug description:
  When doing the regression tests for Python 3.1.2 with Qemu 0.12.5, (Linux 
version 2.6.26-2-686 (Debian 2.6.26-25lenny1)),
  gcc (Debian 4.3.2-1.1) 4.3.2, Python compiled from sources within qemu,
  3 math tests fail, apparently because the floating point unit is buggy. Qmeu 
was compiled from original sources
  on Debian Lenny with kernel  2.6.34.6 from kernel.org, gcc  (Debian 
4.3.2-1.1) 4.3. 

  Regression testing errors:

  test_cmath
  test test_cmath failed -- Traceback (most recent call last):
    File "/root/tools/python3/Python-3.1.2/Lib/test/test_cmath.py", line 364, in
      self.fail(error_message)
  AssertionError: acos0034: acos(complex(-1.0000000000000002, 0.0))
  Expected: complex(3.141592653589793, -2.1073424255447014e-08)
  Received: complex(3.141592653589793, -2.1073424338879928e-08)
  Received value insufficiently close to expected value.

  
  test_float
  test test_float failed -- Traceback (most recent call last):
    File "/root/tools/python3/Python-3.1.2/Lib/test/test_float.py", line 479, in
      self.assertEqual(s, repr(float(s)))
  AssertionError: '8.72293771110361e+25' != '8.722937711103609e+25'

  
  test_math
  test test_math failed -- multiple errors occurred; run in verbose mode for 
deta

  =>

  runtests.sh -v test_math

  le01:~/tools/python3/Python-3.1.2# ./runtests.sh -v test_math
  test_math BAD
   1 BAD
   0 GOOD
   0 SKIPPED
   1 total
  le01:~/tools/python3/Python-3.1.2#

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