etisserant@0: (*
etisserant@0:  * (c) 26 Feb 2001 David Campbell
etisserant@0:  *
etisserant@0:  * Offered to the public under the terms of the GNU General Public License
etisserant@0:  * as published by the Free Software Foundation; either version 2 of the
etisserant@0:  * License, or (at your option) any later version.
etisserant@0:  *
etisserant@0:  * This program is distributed in the hope that it will be useful, but
etisserant@0:  * WITHOUT ANY WARRANTY; without even the implied warranty of
etisserant@0:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
etisserant@0:  * Public License for more details.
etisserant@0:  *
etisserant@0:  * This code is made available on the understanding that it will not be
etisserant@0:  * used in safety-critical situations without a full and competent review.
etisserant@0:  *)
etisserant@0: 
etisserant@0: (*
etisserant@0:  * An IEC 61131-3 IL and ST compiler.
etisserant@0:  *
etisserant@0:  * Based on the
etisserant@0:  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
etisserant@0:  *
etisserant@0:  *)
etisserant@0: 
etisserant@0: 
etisserant@0: (*
etisserant@0:  * This is part of the library conatining the functions
etisserant@0:  * and function blocks defined in the standard.
etisserant@0:  *
etisserant@0:  * SR and RS function blocks
etisserant@0:  * -------------------------
etisserant@0:  *)
etisserant@0: 
etisserant@0: 
etisserant@0: FUNCTION_BLOCK SR
etisserant@0:   VAR_INPUT
etisserant@0:     S1 : BOOL;
etisserant@0:     R  : BOOL;
etisserant@0:   END_VAR
etisserant@0:   VAR_OUTPUT
etisserant@0:     Q1 : BOOL;
etisserant@0:   END_VAR
etisserant@0:   VAR
etisserant@0:     Q_INTERNAL : BOOL;
etisserant@0:   END_VAR
etisserant@0: 
etisserant@0:   Q_INTERNAL := S1 OR ( Q_INTERNAL AND (NOT R));
etisserant@0:   Q1 := Q_INTERNAL;
etisserant@0: END_FUNCTION_BLOCK
etisserant@0: 
etisserant@0: FUNCTION_BLOCK RS
etisserant@0:   VAR_INPUT
etisserant@0:     S : BOOL;
etisserant@0:     R1 : BOOL;
etisserant@0:   END_VAR
etisserant@0:   VAR_OUTPUT
etisserant@0:     Q1 : BOOL;
etisserant@0:   END_VAR
etisserant@0:   VAR
etisserant@0:     Q_INTERNAL : BOOL;
etisserant@0:   END_VAR
etisserant@0: 
etisserant@0:   Q_INTERNAL := (NOT R1) AND (S OR Q_INTERNAL);
etisserant@0:   Q1 := Q_INTERNAL;
etisserant@0: END_FUNCTION_BLOCK