新人求助implement时资源不够的错误

刚入门不久，用的是Vivado2014.4

做一个工程的时候，仿真和综合都通过了，但是貌似是布线失败了，错误如下

[Place 30-640] Place Check : This design requires more RAMB36/FIFO cells than are available in the target device. This design requires 469 of such cell types but only 135 compatible sites are available in the target device. Please analyze your synthesis results and constraints to ensure the design is mapped to Xilinx primitives as expected. If so, please consider targeting a larger device.
[Place 30-640] Place Check : This design requires more RAMB36E1 cells than are available in the target device. This design requires 469 of such cell types but only 135 compatible sites are available in the target device. Please analyze your synthesis results and constraints to ensure the design is mapped to Xilinx primitives as expected. If so, please consider targeting a larger device.
[Place 30-640] Place Check : This design requires more RAMB18 and RAMB36/FIFO cells than are available in the target device. This design requires 938 of such cell types but only 270 compatible sites are available in the target device. Please analyze your synthesis results and constraints to ensure the design is mapped to Xilinx primitives as expected. If so, please consider targeting a larger device.

说的那些RAMB36/FIFO RAMB36E1 RAMB18 都是什么啊？

求各路大神指导。。。是什么地方会产生这种问题呢？