Warning: NUMERIC_STD.TO_INTEGER: metavalue detected

FPGAs said:

Warning: NUMERIC_STD.TO_INTEGER: metavalue detected, returning 0

My modelsim report it, why?
How can i solve it?
plese help me with some idea, thanks a lot!

Click to expand...

MTI Documentation said:

Metavalue detected warning

Meaning
This warning is an assertion being issued by the IEEE numeric_std package. It indicates
that there is an 'X' in the comparison.
Suggested action
The message does not indicate which comparison is reporting the problem since the
assertion is coming from a standard package. To track the problem, note the time the
warning occurs, restart the simulation, and run to one time unit before the noted time. At
this point, start stepping the simulator until the warning appears. The location of the blue
arrow in a Source window will be pointing at the line following the line with the
comparison.
These messages can be turned off by setting the NumericStdNoWarnings variable to 1
from the command line or in the modelsim.ini file.

Click to expand...