Re: Please help me about a problem with LPM library in Quart
In general, Xilinx and Altera have libraries with similar functionality, but with many differences in detail. Altera has e. g. fully parameterizable components for internal RAM while Xilinx has fixed size blocks, so you typically have to instantiate more than one block to build a memory of your choice. Altera actually uses a number of RAM blocks internally, but you don't have to care for.
Except for a few incompatible cases, it should be possible to write an emulation package that provides LPM components through Xilinx library. I did the same in opposite direction for some Xilinx library components.