Translation of RSF-Files into DIMACS Format

Translation of Tristate Variables

Tristate variables will be translated into 2 variables. This translation shall be equal to the translation of Undertaker or !KConfigReader:

• One variable declaring whether the related KConfig variable is permanently selected
• One variable declaring whether the related KConfig variable is selected as a module.
• Only one of these variables can be selected at the same time.

The translation will be done as follows:

• In RSF:

  Item VARIABLE tristate
  

• In DIMACS:

  Not(VARIABLE) or Not(VARIABLE_MODULE)
  

• Meaning:

VARIABLE	VARIABLE_MODULE	Explanation
0	0	VARIABLE is permanently deselected ('n' was selected)
1	0	VARIABLE is permanently selected ('y' was selected)
0	1	VARIABLE is selected as a module ('m' was selected)
1	1	Illegal state

Translation of depends Constraints

Each variable can have multiple depends statements, specifying when the variable can be configured. The variable must remain unconfigured (in case of a Boolean or Tristate variable, it must be set to n), if none of the depends statements is fulfilled. Conditions will be translated as follows:

1. One Condition:
   • In RSF:

     depends Variable Condition
     

   • In Boolean formula:

     Not(Condition) implies Not(Variable)
     

   • In DIMACS:

     Condition or Not(Variable)
     

2. Multiple Conditions
   • In RSF:

     depends Variable Condition1
     depends Variable Condition2
     

   • In Boolean formula:

     Not(Condition1) and Not(Condition2) implies Not(Variable)
     

   • In DIMACS:

     Condition1 or Condition2 or Not(Variable)
     

Translation of ItemSelects Constraints

The ​KConfig specification defines select statements as follows:

reverse dependencies: "select" <symbol> ["if" <expr>]

While normal dependencies reduce the upper limit of a symbol (see below), reverse dependencies can be used to force a lower limit of another symbol. The value of the current menu symbol is used as the minimal value <symbol> can be set to. If <symbol> is selected multiple times, the limit is set to the largest selection. Reverse dependencies can only be used with boolean or tristate symbols.

1. Translation of Boolean ItemSelect statements:
   • In RSF:

     ItemSelects BOOLEAN_VAR OTHER_VAR CONDITION
     

   • In Boolean formula:

     (BOOLEAN_VAR and CONDITION) implies OTHER_VAR
     

   • In DIMACS:

     Not(BOOLEAN_VAR) or Not(CONDITION) or OTHER_VAR
     

2. Translation of Tristate ItemSelect statements:
   • In RSF:

     ItemSelects TRISTATE_VAR OTHER_VAR CONDITION
     

   • In Boolean formula:

     (TRISTATE_VAR and CONDITION) implies OTHER_VAR
     (TRISTATE_VAR_MODULE and CONDITION) implies OTHER_VAR_MODULE
     

   • In DIMACS:

     Not(TRISTATE_VAR) or Not(CONDITION) or OTHER_VAR
     Not(TRISTATE_VAR_MODULE) or Not(CONDITION) or OTHER_VAR_MODULE
     

Ranges

Ranges of Integers/Hex variables will not be considered. Since Kconfig supports only == and != comparisons, only values used in constraints will be translated to DIMACS.