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AR# 22684

8.2i XST - XST generates incorrect logic when concatenating a 2-bit vector with a 14-bit vector and muxing for a 16-bit vector

Description

XST generates incorrect logic when concatenating a 2-bit vector with a 14-bit vector and muxing for a 16-bit vector.

Example

assign vector1[15:0] = (condition) ? vector2[15:0] : { ((condition) ? 2_bit_vector : 2'bzz), 14'hzzzz };

Solution

XST cannot correctly process this code as written. To work around this issue, rewrite the code as follows:

assign vector1[15:0] = (condition) ? vector2[15:0] :16'hzzzz);

Xilinx is currently investigating this issue.

AR# 22684
Date Created 03/06/2008
Last Updated 12/15/2012
Status Active
Type General Article