Very Small Single and Double-Precision Values Are Rounded to Zero on Alpha Computers (184101)
The information in this article applies to:
- Microsoft Windows NT Server 4.0 Terminal Server Edition
- Microsoft Windows NT Server 4.0
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Server, Enterprise Edition 4.0
This article was previously published under Q184101 SYMPTOMS
Very small single-precision values (values less than 1.175e-38) and very
small double-precision values (values less than 2.225e-308) are always
rounded towards zero (chopped,) even when the rounding mode is set to round
to nearest or round towards plus or minus infinity.
You can test for the presence of this problem by checking to see if the
double-precision value 1.4e-44 is converted to the single-precision value
of 1.4e-44, but the double-precision value 1.4e-45 is converted to single-
precision value of zero.
CAUSE
This problem is caused by inaccurate rounding in the software emulation of
these very small values. This problem should not be confused with normal
Alpha hardware performance, which rounds ALL very small values to zero. For
information about these very small values, please search the RISC
Programmer's Guide (available in the online documentation in Microsoft
Visual C++ for Alpha) for topics on denormals.
RESOLUTIONTo resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the
Microsoft Knowledge Base:
152734 How to Obtain the Latest Windows NT 4.0 Service Pack
STATUSMicrosoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.
| Modification Type: | Minor | Last Reviewed: | 7/15/2004 |
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| Keywords: | kbbug kbfix KB184101 |
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