Modernize Espresso RoadMap

[sequencer]

Here is the roadmap to modern espresso:

• Switch user documentation to LaTex AsciiDoc, and generate man with pandoc
• Use modern C++ libraries, switch to C++ 17.
• espresso algorithm as a library.
• compatibility cli interface.
• Doxygen based API documentation.
• SMTLIB based formal test framework.

[yqszxx]

0 is on me, start working on it.

[yqszxx]

0 is on me, start working on it.

#12

[sequencer]

1. Remove legacy file format support(aka kiss)

• deprecate it in 2.4, remove it in 3.0
• as well as other deprecations and removes.

2. use antlr4 as parser:

• introduce antlr4 as build dependency
• introduce antlr4-runtime as dependency
• For GitHub release, static link antlr4-runtime
• For Distro release, dynamic link antlr4-runtime

3. Z3 support as test dependency.

• antlr4 is used to parse a truth table.
• a truth table can be converted to SMTLIB(like what we did in Chisel)
• or even use Chisel as test dependency.
• if user wanna verify on their own? we cannot ask them to install chisel.
• so we might need a verification API in the future, introduce Z3 as dependency.

4. we use chisel in the test dependency.
5. espresso as a library(decouple frontend and backend)

• data structure of TruthTable, as we did it in Chisel
• parameter structure of espresso(really)
• TBD in the 3.x

6. Documentation

• follow man rule
• redirect contact information to GitHub issue.
• add pla file(common/src/Synthesis/espresso/pla.5) this tar to man page?

7. Espresso is for PLA

• min term and max term are designed for PLA
• So logic minimization is designed for AND(NAND) and OR(NOR) gates
• And the minimization pass is optimized for local optimization(NAND, NOR)
• So if we wanna optimized for XOR2 or even XOR3. this local optimization cannot get the best result.
• In this case, synthesis tool like abc can replace a specific table to XOR, however this table is generated for pla, which is not optimized for a pla that contains XOR.
• For example, this is what espresso cannot handle.
• so this is a open question, let's leave this to espresso 5.X ;p