What is the difference between the "FixPt" Gateway in in the Matlab Fixed-Point block set and the "Gateway-In" block in the Xilinx block set?
The "Fixed-Point" block set has its own internal data type to represent fixed-point data. The Fixed-Point Gateways convert doubles to/from their representation.
The Xilinx gateways convert doubles to/from our own internal data representation (XFix). By having our own representation, we can ensure that the arithmetic operators in our VHDL package match. System Generator users should use the Xilinx Gateway Blocks.