Implementing Phase Accumulator in VHDL

Just to complete the story:

there is also output resolution. This becomes relevant if lut data is wider than actual output. This could be the case in virtual LUT comptations.

for sine data:virtual computation is based on adding to nearest lower sine lut point a value using some of the left-over accumulator LSBs(their MSB side), and a scale factor derived from lut cosine point.

The reverse is true for cosine point computations.

Finally there is cordic design, I don't know how it works but doesn't use lut.