1. how about the fpu , to execute fp operations ,comparing with other ip core,,FPO(floating point operator), or FFT core? performance, and speed.. 2. where to get the api or lib userguide, for c operation functions and math functions; many c functions are not suitable for float,, double type , such as xil_printf .
1. It's hard to compare these modules since they are used differently. FFT core is a specific module for just FFT operation, FPO is designed for parallell pipelined operations in the fabric, MicroBlaze FPU is used for executing floating-point instruction in MicroBlaze.
MicroBlaze FPU was optimized for a normal execution flow inside MicroBlaze and also for area.
2. You can find most information on how to use floating-point functions in a standard C book.
All C functions will be implemented in MicroBlaze, double-precision will always be handled in software, single-precision will be handled by the FPU if it's implemented.