DOCUMENT:Q72791 06-MAY-2001 [masm] TITLE :FIX: MASM Fails to Generate Error When Real Values Are Too Small PRODUCT :Microsoft Macro Assembler PROD/VER:MS-DOS:5.10,5.10a,6.0,6.0a,6.0b OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Macro Assembler (MASM), versions 5.10, 5.10a, 6.0, 6.0a, 6.0b ------------------------------------------------------------------------------- SYMPTOMS ======== The Microsoft Macro Assembler (MASM) may fail to generate an error when a floating-point value is outside the range of the minimum allowable values. As documented on page 142 of the "Microsoft Macro Assembler Programmer's Guide" included with version 6.0, the limits when using the 4-byte REAL4 (or DD), 8-byte REAL8 (or DQ), or the 10-byte REAL10 (or DT) are as follows: Size Low High ---- --- ---- 4 byte 1.18E-38 3.40E+38 8 byte 2.23E-308 1.79E+308 10 byte 3.37E-4932 1.18E+4932 However, MASM versions 5.1, 5.1a, 6.0, 6.0a, and 6.0b fail to generate an error when exceeding the low end of this range until a value of 3.37E-32752 or smaller for the 4 and 8-byte types and a value of 3.37E-32746 or smaller for the 10-byte type. STATUS ====== Microsoft has confirmed this to be a problem in MASM versions 5.1, 5.1a, 6.0, 6.0a, and 6.0b. This problem was corrected in MASM for MS-DOS version 6.1. MORE INFORMATION ================ The sample program below may be used to illustrate this problem. In the code, two of each of the 4-, 8-, and 10-byte data types are declared and initialized. For each type, one initializing value is used that correctly causes an error, while the other similar initializing value fails to cause an error, even though it should. The declaration of n1, n3, and n5 correctly result in the following error in MASM version 6.0, 6.0a, and 6.0b: error A2071: initializer magnitude too large for specified size MASM versions 5.1 and 5.1a are not as explicit in their error message, but they correctly generate the following overflow error for n1, n3, and n5: error A2029: division by 0 or overflow Neither MASM version 5.1, 5.1a, 6.0, 6.0a, or 6.0b generates an error (as they should) on the declaration of n2, n4, and n6. (These versions fail to produce the expected error for any number smaller than the values listed above for each data type.) Sample Code ----------- ; Assemble options needed: none .MODEL large .STACK 4096 .DATA n1 DD 1.18E-32752 ;Causes error n2 DD 1.18E-32751 ;Should cause error, but doesn't n3 DQ 2.23E-32752 ;Causes error n4 DQ 2.23E-32751 ;Should cause error, but doesn't n5 DT 3.37E-32746 ;Causes error n6 DT 3.37E-32745 ;Should cause error, but doesn't .CODE start: mov ax, 4C00h int 21h END start Additional query words: 5.10 5.10a 6.00 6.00a 6.00b buglist6.00 buglist6.00a buglist6.00b fixlist6.10 ====================================================================== Keywords : Technology : kbMASMsearch kbAudDeveloper kbMASM600 kbMASM600a kbMASM600b Version : MS-DOS:5.10,5.10a,6.0,6.0a,6.0b Solution Type : kbfix ============================================================================= 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 2001.