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AR# 22167

8.1i XST - INTERNAL_ERROR:Xst:cmain.c:3068:1.158.12.1 - Creating DSP functions

Description

Keywords: DSP, MAC, MACC, MAD, MADD, multiply, accumulate, add

Urgency: Standard

General Description:
XST generates an internal error in the following scenario:

- A multiply accumulate (MAC) or a multiply add (MAD) is described in a hierarchical block.
- This block is instantiated at least 2 times.
- There are FFs on the input of the mac/multadd which are outside the instantiated block.

Solution

To work around this problem, put the inferred registers inside of the MAC / MAD block.

This issue will be fixed in ISE 8.2i.
AR# 22167
Date Created 09/04/2007
Last Updated 01/08/2009
Status Archive
Type General Article