219
5-20 Binary Calculations
Binary calculation instructions — ADB(50), SBB(51), MLB(52), DVB(53),
ADBL(––),
SBBL(––), MBS(––), MBSL(––), DBS(––), and DBSL(––) — perform
arithmetic operations on hexadecimal data.
Four of these instructions (ADB(50), SBB(51), ADBL(––), and SBBL(––)) can
act
on
both normal and signed data, two (MLB(52) and DVB(53)) act only on nor
-
mal
data, and four (MBS(––),
MBSL(––), DBS(––), and DBSL(––)) act only on
signed binary data.
The
addition and subtraction instructions include CY in the calculation as well as
in
the result. Be sure to clear
CY if its previous status is not required in the calcu
-
lation,
and to use
the result placed in CY
, if required, before it is changed by the
execution
of any other instruction. STC(40) and CLC(41) can be used to control
CY. Refer to 5-19 BCD Calculations.
Signed
binary
addition and subtraction instructions use the underflow and over
-
flow flags (UF and OF) to indicate whether the result exceeds the acceptable
range for 16-bit or 32-bit signed binary data. Refer to page 29 for details on
signed binary data.
5-20-1 BINARY ADD – ADB(50)
Au: Augend word (binary)
IR, SR, AR, DM, HR, TC, LR, #
Ad: Addend word (binary)
IR, SR, AR, DM, HR, TC, LR, #
Ladder Symbols
Operand Data Areas
R: Result word
IR, SR, AR, DM, HR, LR
ADB(50)
Au
Ad
R
@ADB(50)
Au
Ad
R
Description When the execution condition is OFF, ADB(50) is not executed. When the ex-
ecution condition is ON, ADB(50) adds the contents of Au, Ad, and CY, and
places the result in R. CY will be set if the result is greater than FFFF.
Au + Ad + CY CY R
ADB(50)
can also be used
to add signed binary data. The underflow and over
-
flow
flags (SR 25404 and SR 25405) indicate
whether the result has exceeded
the
lower or upper limits of the
16-bit signed binary data range. Refer to page
29
for details on signed binary data.
Flags ER: Indirectly
addressed
DM word is non-existent. (Content of
:
DM word is
not BCD, or the DM area boundary has been exceeded.)
CY: ON when the result is greater than FFFF.
EQ: ON when the result is 0.
OF: ON when the result exceeds +32,767 (7FFF).
UF: ON when the result is below –32,768 (8000).
Binary Calculations Section 5-20
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