227
In the case below, 1,799,100,099 + (–282,751,929) = 1,516,348,100
(6B3C167D + EF258C47 = 5A61A2C4). Neither OF nor UF are turned ON.
Au
+ 1 : LR 21
Au : LR 20
Ad + 1 : DM 001
1
Ad : DM 0010
6B3C 167D
EF25
8C47
0
+
R + 1 : DM 0021
R : DM 0020
A2C45A61
0
CY (Cleared with CLC(41))
UF (SR 25405)
0
OF (SR 25404)
Note The
status of the CY flag can be ignored when adding signed binary data since it
is relevant only in the addition of normal hexadecimal values.
5-20-6 DOUBLE BINARY SUBTRACT – SBBL(––)
Mi: First minuend word (binary)
IR, SR, AR, DM, HR, TC, LR
Su: First subtrahend word (binary)
IR, SR, AR, DM, HR, TC, LR
Ladder Symbols
Operand Data Areas
R: First result word
IR, SR, AR, DM, HR, LR
SBBL(––)
Mi
Su
R
@SBBL(––)
Mi
Su
R
Limitations Mi
and Mi+1 must be in the
same data area, as must Su and Su+1, and R and
R+1.
Description When
the execution condition is OFF
, SBBL(––) is not executed.
When the ex
-
ecution
condition is ON, SBBL(––) subtracts CY and
the eight-digit value in Su
and
Su+1 from the eight-digit value in Mi and Mi+1, and places the result in R and
R+1.
If the result is negative, CY is set and the 2’
s complement of
the actual re
-
sult
is placed in R+1
and R. Use the DOUBLE 2’
s COMPLEMENT instructions to
convert the 2’s complement to the true result.
Mi
+ 1
Mi
Su + 1
Su
R + 1
R
–
CY
CY
SBBL(––)
can also be used to subtract signed
binary data. The underflow and
overflow flags (SR 25404 and SR 25405) indicate whether the result has ex-
ceeded
the lower or upper limits of the 32-bit signed binary data
range. Refer to
page 29 for details on signed binary data.
Binary Calculations Section 5-20
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