[Python-checkins] cpython (merge 3.2 -> default): Issue #13889: Merge fix from 3.2.

[mark.dickinson]

http://hg.python.org/cpython/rev/7eca620feb10
changeset:   76321:7eca620feb10
parent:      76319:88f8ef5785d7
parent:      76320:dfc9a98a5fef
user:        Mark Dickinson <mdickinson at enthought.com>
date:        Sun Apr 15 15:12:37 2012 +0100
summary:
  Issue #13889: Merge fix from 3.2.

files:
  Include/pyport.h |  24 ++++++++++++++++++++++++
  Misc/NEWS        |   4 ++++
  2 files changed, 28 insertions(+), 0 deletions(-)


diff --git a/Include/pyport.h b/Include/pyport.h
--- a/Include/pyport.h
+++ b/Include/pyport.h
@@ -557,6 +557,30 @@
         _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
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,10 @@
 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 #2377: Make importlib the implementation of __import__().
 
 - Issue #1559549: ImportError now has 'name' and 'path' attributes that are set

-- 
Repository URL: http://hg.python.org/cpython