A Logic Block is what gives FPGA its ability to take on different hardware configurations. A DSP Block is designed to carry out digital signal processing functions. A Switch Matrix in FPGA is used to connect different Logic Block, Memory Block and DSP Block together.

What's so special about DSPs? Why are they put in FPGAs by default? Also, a DSP can be considered an fixed-function ASIC, right? If so, have there been experiments where people embed ASICs within FPGAs? This would increase the design space of chips: now we can choose an FPGA and then choose what ASICs to put on it to best support our workloads. What if we put an AISC optimized for deep learning / matrix multiplication as a "tensor block" inside an FPGA, just like the "DSP block"?