I have written a matlab function for a constellation mapper and I want to create a Fixed-point version of that code for implementation on FPGA. I know matlab has a specific toolbox for fixed-point conversion but i want to do this manually. My specific question is:
1) which parts of the code would require this conversion? i mean do all inputs, outputs, temporary variables need to be converted to a fixed point format ?
2) What are the steps that I should follow to do this conversion? i read that converting from floating point to fixed is no more, no less than scaling numbers. but I'm not quite sure how I go about doing this. Also, I want this fixed point representation to be of a custom length, not necessarily equal to standard lengths like 8, 16, 32-bits .
PS: I don't want to compare the performance of the fixed point code and floating point code in the time being