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MICROPROCESSOR INSTRUCTION REFERENCE->CHK

CHK    Check Data Register against Bounds

If Dn < 0 or Dn > (<ea>) then TRAP


Assembler Syntax:  CHK <ea>,Dn


<ea> - data only

Size:  Word, Long 1

1   68020 and CPU32 only

Compares the value in the data register specified in the instruction to zero and to the upper bound (effective address operand).  The upper bound is a twos complement integer.  If the register value is less than zero or greater than the upper bound, a CHK instruction exception, vector number 6, occurs.

Condition Codes:

N    Set if Dn < 0, clear if Dn > (<ea>) else undefined
Z    Undefined
V    Undefined
C    Undefined
X    Not affected

    

	Allowable Addressing Modes

	CHK	Dn,Dn
	CHK	(An),Dn
	CHK	(An)+,Dn
	CHK	-(An),Dn
	CHK	(d16,An),Dn
	CHK	(d8,An,Xn),Dn
	CHK	(bd,An,Xn),Dn
	CHK	([bd,An,Xn],od),Dn
	CHK	([bd,An],Xn,od),Dn
	CHK	(xxx).W,Dn
	CHK	(xxx).L,Dn
	CHK	#(data),Dn
	CHK	(d16,PC),Dn
	CHK	(d8,PC,Xn),Dn
	CHK	(bd,PC,Xn),Dn
	CHK	([bd,PC,Xn],od),Dn 1
	CHK	([bd,PC],Xn,od),Dn 1