Description

When synthesizing a multiplier which is pipelined by 5 stages or above, I get the below error in XST. How do I fix it?

FATAL_ERROR:Xst:xstmacrodsprainiernode.c:473:1.12 - Invalid number of registers for A: 3 Process will terminate.

Solution

This issue has been fixed in the upcoming 11.1.

To work around it, you may either change mult_style to "lut" or "pipe_lut", or manually add an extra pipeline stage to the existing 4

levels.