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RS
D-R Exchange
The instruction "RS" directs the computer to exchange the contents of D (both D and d
registers) with the contents of the R register. The setting of the Decimal Wheel has no effect
on this operation. This instruction has a special use in the following cases exclusively:
•
In multicard programs, to temporarily store the contents of the D (d,D) register in R, when
a new card has to be read to continue the program. During this temporary storage no
instruction affecting the R register can be executed.
___________________________________________________________________________________
INSTRUCTION
_ RESULT_________________________________
RS
d,D
⇔
R
EXAMPLE:
Decimal Wheel set at 2.
_____________________________________
d
D
R
BEFORE
2.25 45.50
135798624211345
RS
AFTER 135798824211345
2.25 45.50
BEFORE
135798824211345 2.25 45.50
RS
AFTER
2.25 45.50
135798624211345
•
To use the D register for data storage in the second phase of a program when, in the first
phase, this register has been used to store instructions which are no longer needed. the RS
instruction must be preceded by R* (usually inoperative).
EXAMPLE:
Decimal Wheel set at 2.
_____________________________________
d
D
R
BEFORE Instructions
18.12
R*
RS
AFTER - -
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