DOCUMENT:Q43276 06-NOV-1999 [win16sdk] TITLE :Applications and the Math Coprocessor Under Windows PRODUCT :Microsoft Windows Software Development Kit PROD/VER:WINDOWS:3.0,3.1 OPER/SYS: KEYWORDS:kb16bitonly ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 ------------------------------------------------------------------------------- SUMMARY ======= When an application for Microsoft Windows is run on a machine with a math coprocessor, the application can use inline floating-point instructions to take the fullest advantage of the hardware. MORE INFORMATION ================ Specifying the -FPi option on the C compiler command line causes the Microsoft C optimizing compiler to produce inline 80x87 math coprocessor code for any floating-point math operation. If this code is linked with the WIN87EM.LIB library and a math coprocessor is present in the system at run time, the application will use the inline floating-point instructions for its math operations. If no coprocessor is available at run time, code in the emulator library evaluates floating-point expressions. An application compiled for the MS-DOS environment with the -FPi option checks for the coprocessor at run time and modifies its code accordingly: if there is a coprocessor, it uses inline floating-point instructions; if there is no coprocessor, it calls software routines to emulate the coprocessor. In the Windows environment, these run-time modifications are not performed because the Windows kernel fixes up the floating point references as it loads the application's code segments (the kernel is aware of the presence or absence of the numeric coprocessor). This means that an application for the Windows environment compiled with the -FPi option will perform direct, inline floating-point instructions without run-time coprocessor-checking. Consequently, there is no need to link in the Microsoft C Compiler inline floating- point module, which removes the run-time coprocessor-checking. Additional query words: 3.00 no32bit 3.10 ====================================================================== Keywords : kb16bitonly Technology : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310 Version : WINDOWS:3.0,3.1 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.