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MICROPROCESSOR INSTRUCTION REFERENCE->TAS
TAS Test and Set an Operand
ColdFire 4 Series Only
Test operand and set N and Z as appropriate.
Set high order bit (bit 7) of operand
Assembler Syntax: TAS <ea>
The instruction tests the current value of the operand and sets the N and Z condition bits appropriately. It also sets the high-order bit of the operand. The operand uses a read-modify-write memory cycle that completes the operation without interruption. This instruction supports use of a flag or semaphore to coordinate several processors.
N Set if most significant bit of operand was set
Z Set if result was zero, else cleared
V Always cleared
C Always cleared
X Not affected
|Allowable Addressing Modes|