We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

AR# 21223

7.1i XST - XST creates incorrect logic for signed multiplier


Keywords: embedded, Virtex-4, Virtex-II

In my design, when the operands are used twice (once for unsigned and once for signed), XST creates one unsigned multiplier:

C <= A*B;
S <= tmp + signed(A)*signed(B);

XST only infers one multiplier for C and an adder for S. The logic inferred for S is incorrect.


This problem has been fixed in the latest 7.1i Service Pack available at:
The first service pack containing the fix is 7.1i Service Pack 2.
AR# 21223
Date 01/07/2009
Status Archive
Type General Article
Page Bookmarked