Start having nicer stage 4 error messages.
(*
* This file is part of matiec - a compiler for the programming
* languages defined in IEC 61131-3
*
* Copyright (C) 2011 Mario de Sousa (msousa@fe.up.pt)
*
* See COPYING and COPYING.LESSER files for copyright details.
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
* This code is made available on the understanding that it will not be
* used in safety-critical situations without a full and competent review.
*)
(*
* An IEC 61131-3 compiler.
*
* Based on the
* FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
*
*)
(*
* This is part of the library conatining the functions
* and function blocks defined in the standard.
*
* SR and RS function blocks
* -------------------------
*)
(* The standard defines the SR FB thus:
+-----+
S1----------------| >=1 |---Q1
+---+ | |
R------O| & |----| |
Q1------| | | |
+---+ +-----+
*)
FUNCTION_BLOCK SR
VAR_INPUT
S1, R : BOOL;
END_VAR
VAR_OUTPUT
Q1 : BOOL;
END_VAR
Q1 := S1 OR ((NOT R) AND Q1);
END_FUNCTION_BLOCK
(* The standard defines the RS FB thus:
+---+
R1----------------O| & |---Q1
+-----+ | |
S-------| >=1 |----| |
Q1------| | | |
+-----+ +---+
*)
FUNCTION_BLOCK RS
VAR_INPUT
S, R1 : BOOL;
END_VAR
VAR_OUTPUT
Q1 : BOOL;
END_VAR
Q1 := (NOT R1) AND (S OR Q1);
END_FUNCTION_BLOCK