lib/sema.txt
author mjsousa
Wed, 15 Apr 2015 23:25:07 +0100
changeset 999 dd50a82ae8da
parent 251 5e7457efbb8f
permissions -rw-r--r--
transform CASE into if()..else if().. -> fixes 2 bugs (1)case within case statements, and (2)repeated elements in case options
(*
 * (c) 2011 Edouard Tisserant
 *
 * Fake semaphore support, for non preemptive implementation.
 *
 *)


FUNCTION_BLOCK SEMA
  VAR_INPUT
    CLAIM : BOOL;
    RELEASE : BOOL;
  END_VAR
  VAR_OUTPUT
    BUSY : BOOL;
  END_VAR
  VAR
    Q_INTERNAL : BOOL;
  END_VAR

  Q_INTERNAL := CLAIM OR ( Q_INTERNAL AND (NOT RELEASE));
  BUSY := Q_INTERNAL;

END_FUNCTION_BLOCK