Difference in floating point and fixed point arithmetic in vhdl.

Fixed point is really just integer arithmetic with an offset (its not just similar - it is completely identical). It uses 2s compliment for signed arithmetic. https://en.wikipedia.org/wiki/two%27s_complement

Floating point uses a different number format complety. It uses a sign bit, and exponent and a mantissa. https://en.wikipedia.org/wiki/floating_point

Fixed point has a fixed range with fixed precision based on the number of bits.

Floating has a fixed range with floating precision, bit width is always fixed.

Floating point is computationally expensive, uses a lot of resources and has a high latency.

Fixed point is cheap, few resources and low latency.