NAME

       MOKA -  Model checker ancestor

SYNOPSIS

       moka [-VDB] fsm_filename ctl_filename

DESCRIPTION

       moka is a CTL model checker.

       Made  to run on FSM or RTL descriptions, moka supports the same VHDL subset as syf or boom
       (for further informations about  this  subset  see  SYF(1),  BOOM(1),  FSM(5),  VBE(5)  ).
       Nevertheless  moka  imposes that each register of the behavioral description have the same
       clock condition and that there are no tristate or multiplexed buses.  In  particular  VHDL
       type MUX_BIT and WOR_BIT aren't not supported.
       First  of all moka build the fonction transition of the FSM using a Reduced Ordered Binary
       Decision Diagrams representation.
       It then applies the initial conditions to find the first  state  (keyword  INITIAL  and/or
       RESET_COND in the CTL(5) file format).
       After  it computes a symbolic simulation of the FSM in order to find all reachable states.
       This computation takes into account the assumptions  conditions  (ASSUME  keyword  in  the
       CTL(5) file format).
       moka  finally  verifies  one  by  one  each CTL formulae.  (see CTL(5) for CTL file format
       details).

CTL OPERATORS

       For each CTL sub-expression moka will return the set of states that verifies the  formula.
       For example EX(p) will return the set of reachable states that verifies EX(p).
       CTL operators :
              EX(p)  :  returns  all  states  which  have almost one primary state successor that
              verifies p.
              EU(p,q) : returns all states that are the root of almost one path, such that  p  is
              true until q is always true.
              EG(p)  :  returns  all  states that are the root of almost one path, such that p is
              always true.
              AX(p) : returns all states which  have  all  their  primary  state  successor  that
              verifies p.
              AU(p,q)  : returns all states that are the root of only pathes from which p is true
              until q is always true.
              AG(p) : returns all states that are the root of only pathes, such that p is  always
              true.

ENVIRONMENT VARIABLES

       MBK_WORK_LIB  gives  the  path for the description and the CTL file.  The default value is
              the current directory.

       MBK_CATA_LIB gives some auxiliary pathes for the  descriptions  and  the  CTL  file.   The
              default value is the current directory.

OPTIONS

       -V  Sets  verbose  mode  on. Each step of the model checking  is displayed on the standard
       output.

       -D Sets debug mode on. Each step of the model checking is detailed on the standard output.
       In particular all states set are displayed for each CTL sub-expression.

       -B  The  input  file is a VHDL description using the Alliance VHDL subset (see VBE(5) file
       format).

FSM EXAMPLE

       -- A multi fsm example

       ENTITY example is
       PORT
       (
          ck       : in  BIT;
          data_in  : in  BIT;
          reset    : in  BIT;
          data_out : out BIT
       );
       END example;

       ARCHITECTURE FSM OF example is

          TYPE A_ETAT_TYPE IS (A_E0, A_E1);
          SIGNAL A_NS, A_CS : A_ETAT_TYPE;

          TYPE B_ETAT_TYPE IS (B_E0, B_E1);
          SIGNAL B_NS, B_CS : B_ETAT_TYPE;

       --PRAGMA CURRENT_STATE A_CS  FSM_A
       --PRAGMA NEXT_STATE A_NS     FSM_A
       --PRAGMA CLOCK ck            FSM_A
       --PRAGMA FIRST_STATE A_E0    FSM_A

       --PRAGMA CURRENT_STATE B_CS  FSM_B
       --PRAGMA NEXT_STATE B_NS     FSM_B
       --PRAGMA CLOCK ck            FSM_B
       --PRAGMA FIRST_STATE B_E0    FSM_B

          SIGNAL ACK, REQ, DATA_INT : BIT;

       BEGIN

       A_1 : PROCESS ( A_CS, ACK )
       BEGIN
         IF ( reset = '1' )
         THEN A_NS     <= A_E0;
              DATA_OUT <= '0';
              REQ      <= '0';
         ELSE
         CASE A_CS is
           WHEN A_E0 =>
             IF ( ACK ='1') THEN A_NS <= A_E1;
                            ELSE A_NS <= A_E0;
             END IF;
             DATA_OUT <= '0';
             REQ      <= '1';
           WHEN A_E1 =>
             IF ( ACK ='1') THEN A_NS <= A_E1;
                            ELSE A_NS <= A_E0;
             END IF;
             DATA_OUT <= DATA_INT;
             REQ      <= '0';
         END CASE;
         END IF;
       END PROCESS A_1;

       A_2 : PROCESS( ck )
       BEGIN
           IF ( ck = '1' AND NOT ck'STABLE )
           THEN A_CS <= A_NS;
           END IF;
       END PROCESS A_2;

       -------

       B_1 : PROCESS ( B_CS, ACK )
       BEGIN
         IF ( reset = '1' )
         THEN B_NS     <= B_E0;
              DATA_INT <= '0';
              ACK      <= '0';
         ELSE
         CASE B_CS is
           WHEN B_E0 =>
             IF ( REQ ='1') THEN B_NS <= B_E1;
                            ELSE B_NS <= B_E0;
             END IF;
             DATA_INT <= '0';
             ACK      <= '0';
           WHEN B_E1 =>
             IF ( REQ ='1') THEN B_NS <= B_E1;
                            ELSE B_NS <= B_E0;
             END IF;
             DATA_INT <= DATA_IN;
             ACK      <= '1';
         END CASE;
         END IF;
       END PROCESS B_1;

       B_2 : PROCESS( ck )
       BEGIN
           IF ( ck = '1' AND NOT ck'STABLE )
           THEN B_CS <= B_NS;
           END IF;
       END PROCESS B_2;

       END FSM;

CTL EXAMPLE

       -- A CTL file example

          TYPE A_ETAT_TYPE IS (A_E0, A_E1);
          TYPE B_ETAT_TYPE IS (B_E0, B_E1);

          VARIABLE A_NS, A_CS : A_ETAT_TYPE;
          VARIABLE B_NS, B_CS : B_ETAT_TYPE;

          VARIABLE    ck       : BIT;
          VARIABLE    data_in  : BIT;
          VARIABLE    data_out : BIT;
          VARIABLE    reset    : BIT;
          VARIABLE    ack      : BIT;
          VARIABLE    req      : BIT;

          RESET_COND init1 := (reset='1');
          ASSUME     ass1  := (reset='0');

       begin

              prop1 : EX( ack='1' );
              prop2 : AG( req -> AF( ack ) );
              prop4 : AU( req='1', ack='1');

       end;

MOKA EXAMPLE

            moka -V example example

SEE ALSO

        syf (1), fsp (1), fsm (5), ctl (5), vbe(5).