HAVE_PY_SET_53BIT_PRECISION for m68k

[andreas-schwab]

BPO	20904
Nosy	@tim-one, @loewis, @birkenfeld, @mdickinson, @pitrou, @larryhastings, @benjaminp, @skrah, @mirabilos, @andreas-schwab
Files	m68k-float-prec.patch: Patch to implement HAVE_PY_SET_53BIT_PRECISION for m68k

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2014-04-17.04:00:54.565>
created_at = <Date 2014-03-13.07:54:56.217>
labels = ['interpreter-core', 'type-feature']
title = 'HAVE_PY_SET_53BIT_PRECISION for m68k'
updated_at = <Date 2014-04-17.16:43:03.378>
user = 'https://github.com/andreas-schwab'

bugs.python.org fields:

activity = <Date 2014-04-17.16:43:03.378>
actor = 'mark.dickinson'
assignee = 'none'
closed = True
closed_date = <Date 2014-04-17.04:00:54.565>
closer = 'python-dev'
components = ['Interpreter Core']
creation = <Date 2014-03-13.07:54:56.217>
creator = 'schwab'
dependencies = []
files = ['34412']
hgrepos = []
issue_num = 20904
keywords = ['patch']
message_count = 68.0
messages = ['213359', '213420', '213426', '213430', '213431', '213519', '213531', '213540', '214606', '214607', '214609', '214611', '214612', '214613', '214616', '214617', '214618', '214619', '214638', '214641', '214643', '214644', '214645', '214646', '214665', '214676', '214677', '214678', '214679', '214680', '214681', '214682', '214683', '214718', '214719', '214720', '214722', '214723', '214724', '214725', '214729', '214730', '214734', '214744', '214748', '214755', '214771', '214895', '215057', '215470', '215475', '215477', '215480', '215482', '215495', '215498', '215501', '215503', '215505', '215566', '215567', '215569', '215825', '215827', '216623', '216624', '216651', '216708']
nosy_count = 13.0
nosy_names = ['tim.peters', 'loewis', 'georg.brandl', 'mark.dickinson', 'pitrou', 'larry', 'benjamin.peterson', 'Arfrever', 'skrah', 'BreamoreBoy', 'python-dev', 'mirabilos', 'schwab']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue20904'
versions = ['Python 3.5']

[andreas-schwab]

m68k has the same problem as x86 with excess floating point precision. The attached patch implements the necessary support for HAVE_PY_SET_53BIT_PRECISION.

[mdickinson]

Technically I guess this counts as a new feature. It would be painful to have to wait for 3.5, though. I wonder whether we can sneak this in after 3.4 is released?

Is the __mc68000__ #define specific to gcc?

[andreas-schwab]

I don't know of any other compiler on m68k.

[skrah]

Mark Dickinson <report@bugs.python.org> wrote:

I wonder whether we can sneak this in after 3.4 is released?

+1. m68k affects a relatively small group of people, and Andreas Schwab is
the gcc m68k port maintainer, so ...

[larryhastings]

Does Python still officially support m68k?

[andreas-schwab]

I have modified the patch to include a configure check to set HAVE_GCC_ASM_FOR_MC68881 and use that instead of __mc68000__.

[pitrou]

I don't think fixing bugs on a specific architecture counts as a new feature.

Does Python still officially support m68k?

Certainly not. We haven't had any 68k buildbot in ages (not sure we ever had any, actually).

Andreas, have you signed a contributor's agreement? You can do it online at http://www.python.org/psf/contrib/contrib-form/

[larryhastings]

I'm happy to accept the change for 3.4.1, but I'm not going to cherry-pick a fix for an unsupported platform after rc3.

[BreamoreBoy]

It strikes me as strange that we'd allow code churn for an unsupported platform, can someone explain the rationale behind this please.

[andreas-schwab]

What do you mean with code churn?

[BreamoreBoy]

Code churn is defined as lines added, modified or deleted to a file from one version to another.

[andreas-schwab]

That's a very broad definition, I didn't know that python is such a hostile environment.

[benjaminp]

Ignore Mark Lawrence.