signaltap: can't fit blocks

Please have a look at the fitter report, but be aware that the implementation bits are not the used bits.

Let's give you an example:

your device has 3 M10K Blocks, so 30.000 Bits available and you have one instance, let's say a FIFO which needs 21.000 Bits of them, then there should be 9K Bits left, but you can not split a M10K into pieces, so all three Blocks are full.

That also happens if you have two fifos with 128-Bit, then 2 M10K Blocks should be used...