Intel MCS48 User Manual page 96

INSTRUCTION SET
CPL
FO
Complement
Flag
(Not
in
8021, 8022)
100
1
10
1
The
setting of flag
is
complemented; one
is
changed
to zero,
and
zero
is
changed
to one.
F0-*-
NOT
(F0)
CPL
F1
Complement
Flag
1
(Not
in
8021, 8022)
10
11
10
1
The
setting of flag
1
is
complemented; one
is
changed
to zero,
and
zero
is
changed
to one.
(F1H-NOT
(F1)
DA A
Decimal
Adjust
Accumulator
10
1
111
The
8-bit
accumulator
value
is
adjusted
to
form
two
4-bit
Binary
Coded
Decimal (BCD)
digits
following
the binary addition
of
BCD
numbers.
The
carry
bit
C
is
affected.
If
the contents
of
bits
0-3 are
greater
than
nine,
or
if
AC
is
one, the accumulator
is
incremented by
six.
The
four
high-order
bits
are
then checked.
If
bits
4-7 exceed
nine, or
if
C
is
one, these
bits
are
increased by
six.
If
an overflow occurs,
C
is
set to
one.
Example:
Assume
accumulator contains 10011011.
DA
A
ACC ADJUSTED TO
00000001
WITH C SET
C
AC
7 4 3
10
1
10
11
110
ADD
SIX
TO
BITS 0-7
10 10
1
110
ADD
SIX
TO
BITS 4-7
1 1
OVERFLOW TO
C
DEC A
Decrement Accumulator
00 00
111
The
contents
of
the
accumulator
are
decremented by
one.
(A)*-
(A)-1
Mnemonics
copyright
Intel
Corporation 1976.
4-14