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AR# 22625

10.1 XST - XST runs out of memory or takes a long time to synthesize with designs that contain nested loops


Keywords: synthesis, 10.1, nested loops, out of memory

When using nested loops, XST either takes a long time or an "out of memory" error occurs.


Xilinx highly recommends avoiding complex loops in synthesis, as most synthesis tools have problems with this coding style. It is always best to write code that it is easy for the synthesis tool to utilize.

For more information on coding for synthesis, see the Synthesis and Simulation Design Guide accessible at:

If you must use loops, change the "for" loops to "while" loops because XST handles "while" loops better than "for" loops.

XST is working on addressing this issue in the future releases of software.
AR# 22625
Date Created 03/06/2008
Last Updated 06/23/2008
Status Active
Type General Article