Microsoft KB Archive/103654

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Floating-Point Calculations May Be Incorrect on Alpha and MIPS


The information in this article applies to:

  • Microsoft Windows NT Server version 3.1
  • Microsoft Windows NT Workstation version 3.1
  • Microsoft Windows NT Advanced Server, version 3.1


When you are using Calculator under Windows NT on the DEC Alpha computer or other RISC-based computer, you may experience floating-point errors in your calculations.

This problem does not occur on x86-based computers.


Microsoft has confirmed this to be a problem in Windows NT version 3.1 and Windows NT Advanced Server version 3.1. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.


Steps to Reproduce Problem

  1. In the Accessories group, open Calculator, choose Scientific from the View menu.
  2. Find the sin of 90 (degrees in decimal mode); the result is 1 (correct).
  3. Change to octal, binary, hexadecimal, or back to decimal mode; the results are all 0 (incorrect).
  4. Find the sin of 90 again, then take the inv sin of the 1; the result is 89.99999914623--it should be 90.
  5. Find the cos of 200 (gradients in decimal mode); the result is -1 (correct).
  6. Take the inv cos of the -1; the result is 199.9999990514--it should be 200.

Additional query words: prodnt wrong error miscalculate

Keywords : kbtool
Issue type :
Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW310 kbWinNTSsearch kbWinNTS310 kbWinNTAdvSerSearch kbWinNTAdvServ310 kbWinNTS310xsearch kbWinNT310xSearch kbWinNTW310Search

Last Reviewed: October 27, 2000
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