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BCLR
Operation:
Assembler
Syntax:
Attributes:
Description:
code appropriately, then clears the bit. 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 least significant bit. The bit number for this operation
can be specified in either of two ways:
1. Immediate — The bit number is specified by a second instruction word.
2. Register — The specified data register contains the bit number.
Condition Codes:
X
N
Z
—
—
*
X
Not affected
N
Not affected
Z
Set if the bit tested is zero. Cleared otherwise
V
Not affected
C
Not affected
Instruction Format (Bit Number Static, specified as immediate data):
15
14
13
0
0
0
0
0
0
CPU32
REFERENCE MANUAL
Test a Bit and Clear
(〈bit number〉 of Destination) → Z;
0 → 〈bit number〉 of Destination
BCLR Dn, 〈ea〉
BCLR #〈data〉, 〈ea〉
Size = (Byte, Long)
Tests a specified bit in the destination operand, sets the Z condition
V
C
—
—
12
11
10
9
0
1
0
0
0
0
0
0
INSTRUCTION SET
8
7
6
5
0
1
0
0
BCLR
4
3
2
1
EFFECTIVE ADDRESS
MODE
REGISTER
BIT NUMBER
MOTOROLA
0
4-39
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