AR# 38210

Design Assistant for XST Help resolving "HDLCompiler:679: Case statement is complete. others clause is never selected." warning

描述

Refer to this Answer Record for help resolving a "HDLCompiler:679: Case statement is complete. others clause is never selected" warning.

Note: This Answer Record is a part of the Xilinx Solution Center for XST (Xilinx Answer 38927). The Xilinx Solution Center for XST is available to address all questions related to XST. Whether you are starting a new design or troubleshooting a problem, use the Solution Center for XST to guide you to the right information.

解决方案

This message is issued when there is a VHDL 'case' statement with 'others' clause; but the 'case' statement is complete even without the 'others' clause.

WHAT NEXT:

Remove the 'others' clause, and re-run XST

EXAMPLE:

Consider the following RTL

case sel is
when "00" => do <= di(3);
when "01" => do <= di(2);
when "10" => do <= di(0);
when "11" => do <= di(1);
when others => null;
end case;
end if;

Here 'sel' is a 2-bit signal and all the 4 possible values of it are already enumerated in the 'case' statement. Therefore the 'others' clause does not really get triggered.

链接问答记录

主要问答记录

Answer Number 问答标题 问题版本 已解决问题的版本
38927 面向 XST 的 Xilinx 解决方案中心 N/A N/A

相关答复记录

Answer Number 问答标题 问题版本 已解决问题的版本
40379 Design Assistant for XST Help understanding the XST report to resolve errors\warnings N/A N/A
AR# 38210
日期 12/15/2012
状态 Active
Type 综合文章