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NBCD
Negate Decimal with Extend
NBCD
Operation:
Assembler
Syntax:
Attributes:
0- (Destination1 0) - X
=>
Destination
NBCD (ea)
Size
=
(Byte)
Descriptio n:
Subtracts the destination operand and the extend bit from zero. The operation is
performed using binary coded decimal arithmetic. The packed BCD result is saved in the
destination location. This instruction produces the tens complement of the destination if the
extend bit is zero, or the nines complement if the extend bit is one.
Condition Codes:
X
N
z
v
u
u
X Set the same as the carry bit.
N Undefined.
C
Z
Cleared if the result is non-zero. Unchanged otherwise.
V
Undefined.
C Set if a decimal borrow occurs. Cleared otherwise.
NOTE
Normally the
Z
condition code bit is set via programming before the start of the
operation. This allows successful tests for zero results upon completion of
multiple precision operations.
Instruction Format:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
EFFECTIVE ADDRESS
0
1
0
0
1
0
0
0
0
0
I
MODE
REGISTER
o
MOTOROLA
4-118
INSTRUCTION SET
CPU32 REFERENCE MANUAL
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