From 18e3d81f96a592a0307fa41645017483eabcfc51 Mon Sep 17 00:00:00 2001 From: Mark Dickinson Date: Sun, 15 Apr 2012 15:10:56 +0100 Subject: Issue #13889: On MSVC builds, set FPU control word at runtime for all string <-> float conversions. Patch by Samuel Iseli and Stefan Krah. --- Include/pyport.h | 24 ++++++++++++++++++++++++ Misc/NEWS | 4 ++++ 2 files changed, 28 insertions(+) diff --git a/Include/pyport.h b/Include/pyport.h index 269ba68..4ef0db2 100644 --- a/Include/pyport.h +++ b/Include/pyport.h @@ -557,6 +557,30 @@ 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 diff --git a/Misc/NEWS b/Misc/NEWS index 69dd691..b045742 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -10,6 +10,10 @@ What's New in Python 3.2.4 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 #14474: Save and restore exception state in thread.start_new_thread() while writing error message if the thread leaves a unhandled exception. -- cgit v0.12