Complex sentence: The function of the i8255 is to provide 24 parallel input/output lines but the functionality of the i8255 is now mostly embedded in a larger VLSI chip as a sub-function.
Split into simpler sentences: The function of the i8255 is to provide 24 parallel input/output lines. The functionality of the i8255 is now mostly embedded in a larger VLSI chip as a sub-function.