Section 10: The Index Register and Loop Control 111

False (nnnnn > xxx)

 

True (nnnnn xxx)

 

 

 

 

instruction

 

 

 

 

 

´sV

 

 

 

 

loop

t.1

 

 

 

 

 

Instruction

exit loop

 

 

 

For e: given nnnnn.xxxyy, decrement nnnnn to nnnnn - yy, compare it to xxx, and skip the next program line if the new value satisfies nnnnn xxx. This allows you to exit a loop at this point when nnnnn becomes less than or equal to xxx.

For example, loop iterations will alter these control numbers as follows:

Iterations

Operation

0

1

2

3

4

 

 

 

 

 

 

I

0.00602

2.00602

4.00602

6.00602

8.00602

 

 

 

 

 

(skip next

 

 

 

 

 

line)

e

6.00002

4.00002

2.00002

0.00002

 

 

 

 

 

(skip next

 

 

 

 

 

line)

 

 

 

 

 

 

 

Examples

Examples: Register OperationsStoring and Recalling

Keystrokes

Display

 

´CLEAR Q

 

Clears all storage registers.

12.3456

12.3456

 

OV

12.3456

Stores in RI.

7 ¤

2.6458

 

O%

2.6458

Storage in R.2 by indirect addressing

 

 

(RI = 12.3456).

lV

12.3456

Recalls contents of RI.