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ADD
Sign of P Field
+
+
-
Sign of
Q
Field
+
-
+
True or Complement Add
Q
Field
True
Comp
Comp
Recomplement only if value of
,
,
,
2
Q
Field is greater than value of
,-
!
P Field
,
,
"
,
3
Change P
~ield
sign only if
-
+
recomplement occurs (changed
si gn shown).
Figure 11.
Sign Control Chart
Multiplication and Division. The sign of each prod-
uct and quotient is determined algebraically from
the signs of its factors, as follows:
+a x +b
+c
-a x +b
-c
-a x -b
+c
+a
+b
+c
-a
+b
-c
-a
-b
+c, etc.
Add (A-21)
Description. The data in the field at the
Q
address
is added to the data in the field at the P address and
the sum replaces the P field data. The
Q
field data
remains unchanged.
In Figure 12, the sum (14) is "looked up" in the
Add table and replaces the 12 at 00500 (P address).
The field mark remains at the high-order position.
When the sum is zero, the sign of the P field is re-
Op Code
I---
Address of P Field
+
Address of
Q
Field
--l
Q
Value at 09400
=
02
P Value at 00500::
12
Sum at P ..
14
(replaces original value)
Figure 12.
Add Instructions - Data Flow
14
,
l
I
I
:
l
SUBTRACT
-
+
+
-
-
-
+
-
+
-
True
Comp
True
True
Comp
,
~
I
I
,
,
,
:
I
-
+
tained. For sums other than zero, the sign of the
field with the larger value is retained. High-order
zeros are supplied if the number of signiRcant digits
in the
Q
field is less than the number of signiRcant
digits in the initial field at P.
The
H/P
indicator is on if the sum is positive and
not zero; the
E/Z
indicator is on if the sum is zero.
Neither indicator is on if the sum is negative.
Execution Time. Execution time varies according
to the number of digits (high-order zeros included)
in the ReId at P and according to whether recomple-
menting is necessary. Recomplement time must be
added to the basic time when the signs of the Relds
at the
Q
and P addresses are different initially and
the absolute numeric value of the
Q
field is greater
than the absolute numeric value of the P field.
Basic Execution Time: T
==
160 + 80D
p
f-Lsec
Recomplement Time:
T
==
80D
p
f-Lsec
Core Storage
~/Il
o
2
f}--. . . . . . . . . -,
<~
Add Table
l~~D---"'''~'
f
I
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