[Python-Dev] How to keep Signaling NaN unchanged when convert hex to single-precision float ?
Hi,
Code snippet 1 and 2 convert an hex to float, but the SNaN is changed to QNaN
automatically. It follows IEEE 754 behavior.
While Code snippet 3 converts an hex to double, and the SNaN keeps.
Is there any solution to keep SNaN float unchanged in Code snippet 1 and 2?
1. >>> i = int('7f81', 16)
>>> cp = pointer(c_uint32(i))
>>> fp = cast(cp, POINTER(c_float))
>>> print(fp.contents.value) # nan
>>> print(struct.pack(">f", fp.contents.value).hex())
7fc1
1. >>> f = struct.unpack('!f', bytes.fromhex('7f81'))[0]
>>> f # nan
>>> hex(struct.unpack('>> i = int('7FF1', 16)
>>> cp = pointer(c_uint64(i))
>>> fp = cast(cp, POINTER(c_double))
>>> print(fp.contents.value)
nan
>>> print(struct.pack(">d", fp.contents.value).hex())
7ff1
Thank you in advance!
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[Python-Dev] How to customize CPython to a minimal set
Hi, all There is a request to run python in a Linux-based embedded resource constrained system with sqlite3 support. So many features are not required, like posixmodule, signalmodule, hashtable ... But seems there are some dependencies among the Modules/Parser/Python/Objects/Programs... Is there a way to tailor CPython 3 to a minimal set with sqlite3 (the less syscalls the better) ? Is it possible to do that? Thank you. ___ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/ECPLKXQ42VNLHD5DP3RG57L3QTJ77FUT/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-Dev] Re: How to customize CPython to a minimal set
Hi, Guido Yes. Micropyhton is also in consideration. But sqlite3 is the first usage. There should be some additional features like numpy, scipy... Not sure if micropython supports well? Or is there a feasible way to strip CPython ? Thanks. From: Guido van Rossum Sent: Monday, July 20, 2020 10:45 PM To: Huang, Yang Cc: python-dev@python.org Subject: Re: [Python-Dev] How to customize CPython to a minimal set Have you considered starting with micropython? It’s made for embedded systems and fully supports Python 3 syntax. Adding sqlite3 support to it will be less work than stripping all the I/O from CPython. —Guido On Mon, Jul 20, 2020 at 06:48 Huang, Yang mailto:yang.hu...@intel.com>> wrote: Hi, all There is a request to run python in a Linux-based embedded resource constrained system with sqlite3 support. So many features are not required, like posixmodule, signalmodule, hashtable ... But seems there are some dependencies among the Modules/Parser/Python/Objects/Programs... Is there a way to tailor CPython 3 to a minimal set with sqlite3 (the less syscalls the better) ? Is it possible to do that? Thank you. ___ Python-Dev mailing list -- python-dev@python.org<mailto:python-dev@python.org> To unsubscribe send an email to python-dev-le...@python.org<mailto:python-dev-le...@python.org> https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/ECPLKXQ42VNLHD5DP3RG57L3QTJ77FUT/ Code of Conduct: http://python.org/psf/codeofconduct/ -- --Guido (mobile) ___ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/CVRL4VTGITKVHLHHTZR5HBCZ4EK2WIPE/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-Dev] Re: How to customize CPython to a minimal set
Thank you for all your comments. I cannot agree any more. I did try but there were so many dependencies. One change all change. Micropython is a choice. But not sure if numpy and sqlite3 can be supported well. And what’s the compatibility of the libs in Pypi. From: Guido van Rossum Sent: Tuesday, July 21, 2020 10:57 PM To: Huang, Yang Cc: python-dev@python.org Subject: Re: [Python-Dev] How to customize CPython to a minimal set I expect it will be unfeasible to strip CPython. If you disagree, try it. ;-) On Mon, Jul 20, 2020 at 22:35 Huang, Yang mailto:yang.hu...@intel.com>> wrote: Hi, Guido Yes. Micropyhton is also in consideration. But sqlite3 is the first usage. There should be some additional features like numpy, scipy... Not sure if micropython supports well? Or is there a feasible way to strip CPython ? Thanks. From: Guido van Rossum mailto:gu...@python.org>> Sent: Monday, July 20, 2020 10:45 PM To: Huang, Yang mailto:yang.hu...@intel.com>> Cc: python-dev@python.org<mailto:python-dev@python.org> Subject: Re: [Python-Dev] How to customize CPython to a minimal set Have you considered starting with micropython? It’s made for embedded systems and fully supports Python 3 syntax. Adding sqlite3 support to it will be less work than stripping all the I/O from CPython. —Guido On Mon, Jul 20, 2020 at 06:48 Huang, Yang mailto:yang.hu...@intel.com>> wrote: Hi, all There is a request to run python in a Linux-based embedded resource constrained system with sqlite3 support. So many features are not required, like posixmodule, signalmodule, hashtable ... But seems there are some dependencies among the Modules/Parser/Python/Objects/Programs... Is there a way to tailor CPython 3 to a minimal set with sqlite3 (the less syscalls the better) ? Is it possible to do that? Thank you. ___ Python-Dev mailing list -- python-dev@python.org<mailto:python-dev@python.org> To unsubscribe send an email to python-dev-le...@python.org<mailto:python-dev-le...@python.org> https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/ECPLKXQ42VNLHD5DP3RG57L3QTJ77FUT/ Code of Conduct: http://python.org/psf/codeofconduct/ -- --Guido (mobile) -- --Guido (mobile) ___ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/OMUGASSNBFJOT3W2ES4OIOQ4LOWMNHHG/ Code of Conduct: http://python.org/psf/codeofconduct/
