Symbolic simulation for correct machine design
William C. Carter, William H. Joyner, et al.
DAC 1979
The effective use of don't cares requires solving several theoretical and practical problems. The theoretical problems are caused by a need to have all tools in a methodology use a consistent semantics of don't cares, so as to guarantee correctness of the final implementation. Several common meanings of "don't care" will be considered, and their respective conditions for design correctness will be derived. The main theoretical result shows that in existing design languages, the following three desirable properties are mutually inconsistent: unrestricted use of non-Boolean values (e.g., X), implementing a large design one partition at a time, and assurance of correctness of the final implementation. A practical solution to this problem involves several issues: specifying don't cares in a language description, deriving them during high-level synthesis, and optimizing logic in their presence. Experimental results showing the impact of don't cares on logic quality are presented. © 1998 IEEE.
William C. Carter, William H. Joyner, et al.
DAC 1979
Daniel Brand, Tsutomu Sasao
IEEE TC
Reinaldo A. Bergamaschi, Subhrajit Bhattacharya, et al.
IEEE Design and Test of Computers
Reinaldo A. Bergamaschi, Youngsoo Shin, et al.
CODES+ISSS 2003