238
Description When
the execution condition is OFF
,
SUM(––) is not executed. When the ex
-
ecution condition is ON, SUM(––) adds either the contents of words R
1
to
R
1
+N–1
or the bytes in words R
1
to R
1
+N/2–1 and outputs that value to the desti
-
nation
words (D and D+1). The data can be summed as binary or BCD and will
be output in the same form. Binary data can be either signed or unsigned.
The function of bits in C are shown in the following diagram and explained in
more detail below.
15 14 13 12 11 00
Number
of items in range (N, BCD)
Number of words or number of bytes
001 to 999
Starting byte in R1 (when bit 13 is ON)
1 (ON): Rightmost
0 (OFF): Leftmost
Addition units
1 (ON): Bytes
0 (OFF): Words
C:
Data type
1 (ON): Binary
0 (OFF): BCD
Data type (when bit 14 is ON)
1 (ON):
Signed binary
0 (OFF):
Unsigned binary
Number of Items in Range The
number of items within the range (N) is
contained in the 3 rightmost digits of
C,
which must be BCD between 001 and 999. This number will indicate the num
-
ber of words or the number of bytes depending the items being summed.
Addition Units Words will be added if bit 13 is OFF and bytes will be added if bit 13 is ON.
If
bytes are specified, the range can begin
with the leftmost or rightmost byte of
R
1
. The leftmost byte of R
1
will not be added if bit 12 is ON.
MSB LSB
R
1
12
R
1
+1 3 4
R
1
+2 5 6
R
1
+3 7 8
The bytes will be added in this order when bit 12 is OFF: 1+2+3+4....
The bytes will be added in this order when bit 12 is ON: 2+3+4....
Data Type Data
within the range is treated as unsigned binary when bit 14 of C is ON and bit
15
is OFF
, and it is treated as signed binary when both bits
14 and 15 are ON.
Refer to page 29 for details on signed binary data.
Data
within the range is treated as BCD when bit 14 of C is OFF
, regardless of the
status of bit 15.
Flags ER: Indirectly
addressed
DM word is non-existent. (Content of
:
DM word is
not BCD, or the DM area boundary has been exceeded.)
R
1
and R
1
+N–1 are not in the same data area.
The number of items in C is not BCD between 001 and 999.
The data being summed is not BCD when BCD was designated.
EQ: ON when the result is zero.
Special Math Instructions Section 5-21
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