We know that to convert unsigned to signed (precisely, I want to convert a pure binary into CA2 number) we must negate the unsigned number adding, then, + 1. In VHDL I can implement an inverter and an adder that manages the carry in. I have two numbers of 32 bits. Is there another way to implement the sum + 1 using anything cheaper? Is there a solution to manage the carry in using only logic gates?
Electronic – VHDL – Cheapest-Fastest unsigned to signed binary number converter
adderconversionlogic-gatesvhdl
Related Solutions
You are calculating the one-bit parity of your n-bit input. The standard way to do this is with a tree of 2-input XOR gates, which minimises the gate count and depth.
You need to think about how you multiply decimal numbers by hand.
Now, think of your two 4-bit binary numbers as being written in base 4.
Do you see the analogy? Do you see how 2-bit multipliers might apply?
Best Answer
It really isn't worth worrying too much about this detail. Adding 1 to a number is such a common idiom in HDL that synthesis tools have highly-evolved methods for dealing wtih it. Also, most modern FPGAs have dedicated, hard-wired fast carry logic that does not consume logic cells, and that synthesis tools know how to take advantage of.