Microsoft KB Archive/45146

= DOCERR: Some Coprocessor Instructions Not Emulated =

Article ID: 45146

Article Last Modified on 10/17/2003

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APPLIES TO


 * Microsoft Macro Assembler 5.0
 * Microsoft Macro Assembler 5.1 Standard Edition
 * Microsoft Macro Assembler 5.1a
 * Microsoft Macro Assembler 6.0 Standard Edition
 * Microsoft Macro Assembler 6.0a
 * Microsoft Macro Assembler 6.0b
 * Microsoft Macro Assembler 6.1 Standard Edition
 * Microsoft Macro Assembler 6.1a
 * Microsoft Macro Assembler 6.11a

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This article was previously published under Q45146



SUMMARY
The /E option of the Microsoft Macro Assembler (MASM) 5.0 and 5.1 directs the assembler to generate data and code as it is expected by coprocessor emulator libraries. The /FPi option and the OPTION EMULATOR directive provide the same functionality, starting with MASM version 6.0.

The emulator libraries are available with the high-level languages like C, BASIC, FORTRAN, and Pascal. However, the emulator libraries do not support all coprocessor instructions. The following error message will result when an unsupported coprocessor instruction is executed:

run-time error M6107: MATH - floating-point error: unemulated



MORE INFORMATION
The following is the list of unemulated coprocessor instructions in MASM 5.1:   FBLD                    FSAVE FBSTP                  FSETPM FCOS                   FSIN FDECSTP                FSINCOS FINCSTP                FSTENV FINIT                  FUCOM FLDENV                 FUCOMP FNOP                   FUCOMPP FPREM1                 FXTRACT FRSTOR The following is the list of unemulated coprocessor instructions in MASM 6.0 as indicated on page 161 of the &quot;Microsoft Macro Assembler Programmer's Guide&quot;:   FCOS                    FSAVE32 FDECSTP                FSETPM FINCSTP                FSIN FPREM1                 FSINCOS FRSTOR                 FUCOM FRSTOR16               FUCOMP FRSTOR32               FUCOMPP FSAVE                  FXTRACT FSAVE16 However, this list is not complete. When tested with the run-time libraries from Microsoft C/C++ 7.0, the following instructions also result in the M6107 error   FBLD                    FLDENV FBSTP                  FNOP FINIT                  FSTENV In addition, a few of the names are incorrect   FRSTOR16   should be    FRSTORW FRSTOR32  should be    FRSTORD FSAVE16   should be    FSAVEW FSAVE32   should be    FSAVED The following stand-alone assembler sample reproduces the M6107 error for the instruction FBLD. Note that the C run-time code must be brought in. In this case, the small model emulator library (slibce) is used.

Sample Code
; Assemble options needed: /Cx /link slibce

OPTION EMULATOR .MODEL small, C PUBLIC main

.DATA packbcd TBYTE 0

.CODE main: fbld packbcd END

Additional query words: 5.00 5.10 5.10a 6.00 6.00a 6.00b 6.10 6.10a

Keywords: KB45146

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