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MICROPROCESSOR INSTRUCTION REFERENCE->BTST

BTST    Test a Bit

Complement (<bit no.> Destination) -> Z

    

Assembler Syntax:	BTST Dn,<ea>
	BTST #<data>,<ea>

Dn or #<data> specify the bit number

Size:  Byte, Long


Tests a bit in the destination operand and sets the Z condition code appropriately.  When a data register is the destination, any of the 32 bits can be specified by a modulo 32-bit number.  When a memory location is the destination, the operation is a byte operation, and the bit number is modulo 8.  In all cases, bit zero refers to the leaset significant bit.

Condition Codes:

N    Not affected
Z    Set if bit tested = 0, else clear
V    Not affected
C    Not affected
X    Not affected

    

	Allowable Addressing Modes

	Dn,<ea>	#<data>,<ea>

	Dn,Dn		#(data),Dn
	Dn,(An)		#(data),(An)
	Dn,(An)+		#(data),(An)+
	Dn,-(An)		#(data),-(An)
	Dn,(d16,An)		#(data),(d16,An)
	Dn,(d8,An,Xn)
	Dn,(xxx).W
	Dn,(xxx).L
	Dn,#(data)
	Dn,(d16,PC)
	Dn,(d8,PC,Xn)

Dn,Dn and #(data),Dn are long only; all others are byte only.