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AR# 14110

4.1i XST - A compound Boolean equation in XST will occasionally produce incorrect results

Description

Keywords: Boolean, VHDL, equation, result, wrong, incorrect, bad, logic

Urgency: Standard

General Description:
XST may produce incorrect results when coding a "complex" Boolean expression similar to the following:

boolean_out <= not A xor B = not A xor B;

Solution

This problem is fixed in the latest 4.2i Service Pack, available at:
http://support.xilinx.com/support/techsup/sw_updates
The first service pack containing the fix is 4.2i Service Pack 1.
AR# 14110
Date Created 03/07/2002
Last Updated 08/06/2003
Status Archive
Type General Article