Providing various assistances for design modifications on HDL source codes
is important for design reuse and quick design cycle in VLSI CAD. Program s
licing is a software-engineering technique for analyzing, abstracting, and
transforming programs. We show algorithms for extracting/removing behaviors
of specified signals in VHDL descriptions. We also describe a VHDL slicing
system and show experimental results of efficiently extracting components
from VHDL descriptions.