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Issue #13889: On MSVC builds, set FPU control word at runtime for all string <-> float conversions. Patch by Samuel Iseli and Stefan Krah.

This commit is contained in:
Mark Dickinson 2012-04-15 15:19:06 +01:00
parent 9955ad4eb7
commit 9c0baf7202
2 changed files with 28 additions and 0 deletions
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24
Include/pyport.h
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@ -549,6 +549,30 @@ extern "C" {
_Py_set_387controlword(old_387controlword)
#endif
/* get and set x87 control word for VisualStudio/x86 */
#if defined(_MSC_VER) && !defined(_WIN64) /* x87 not supported in 64-bit */
#define HAVE_PY_SET_53BIT_PRECISION 1
#define _Py_SET_53BIT_PRECISION_HEADER \
unsigned int old_387controlword, new_387controlword, out_387controlword
/* We use the __control87_2 function to set only the x87 control word.
The SSE control word is unaffected. */
#define _Py_SET_53BIT_PRECISION_START \
do { \
__control87_2(0, 0, &old_387controlword, NULL); \
new_387controlword = \
(old_387controlword & ~(_MCW_PC | _MCW_RC)) | (_PC_53 | _RC_NEAR); \
if (new_387controlword != old_387controlword) \
__control87_2(new_387controlword, _MCW_PC | _MCW_RC, \
&out_387controlword, NULL); \
} while (0)
#define _Py_SET_53BIT_PRECISION_END \
do { \
if (new_387controlword != old_387controlword) \
__control87_2(old_387controlword, _MCW_PC | _MCW_RC, \
&out_387controlword, NULL); \
} while (0)
#endif
/* default definitions are empty */
#ifndef HAVE_PY_SET_53BIT_PRECISION
#define _Py_SET_53BIT_PRECISION_HEADER

4
Misc/NEWS
View File

@ -9,6 +9,10 @@ What's New in Python 2.7.4
Core and Builtins
-----------------
- Issue #13889: Check and (if necessary) set FPU control word before calling
any of the dtoa.c string <-> float conversion functions, on MSVC builds of
Python. This fixes issues when embedding Python in a Delphi app.
- Issue #14505: Fix file descriptor leak when deallocating file objects
created with PyFile_FromString().