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isValueSpecial

Short summary​

This method checks if a value is a special value (NaN OR infinity OR -inifinity), for details check IEEE 754

:return: TRUE: value is inifinty or -infinity or NaN FALSE: value is not inifinty and not -infinity and not NaN

  • Return type: BOOL

Parameters​

NameTypeCommentKind
valueLREALvalue to checkinput

Code​

Declaration​

METHOD PROTECTED isValueSpecial :BOOL
VAR_INPUT
	(* value to check *)
	value			:LREAL;	
END_VAR
VAR
	(* just to cast the value*)
	lrealAsLword	:POINTER TO LWORD;
END_VAR

Implementation​

lrealAsLword := ADR(value);
isValueSpecial := ((lrealAsLword^ AND THIS^.MASK_FOR_EXPONENT) = THIS^.MASK_FOR_EXPONENT);