Destination Tested -->; Condition Codes;
1 -->; bit 7 of Destination

Compatibility: 68000 Family

Assembler Syntax:
TAS <ea>

Attributes: Size = (Byte)

Description: Tests and sets the byte operand addressed by
the effective address field. The instruction tests the
current value of the operand and sets the N and Z condition
bits appropriately. TAS aslo sets the high-order bit of
the operand. The operation uses a locked or read-modify-
write transfer sequence. This instruction supports use of
a flag or semaphore to coordinate several processors.

Condition Codes:
X Not affected.
N Set if the most significant bit of the operand is currently
set. Cleared otherwise.
Z Set if the operand was zero. Cleared otherwise.
V Always cleared.
C Always cleared.

Instruction Format:
\i1-+--+-+-++u6Effective Address,3Mode,3Reg,

Instruction Fields:
Effective Address field -- Specifies the location of the tested
operand. Only data alterable addressing modes are
allowed as shown:

Related Instructions: