Section 10: Program Editing 117

5.Press gi00. This automatically converts a data storage register into seven additional lines of program memory (if there was not already a i00 instruction remaining at the end of program memory), and it ensures that program execution will branch to line 00 after the program is run.

6.Key in the instruction(s) being added.

7.Key in the instruction that originally immediately followed the point at which the new instruction(s) are being added — that is, the first instruction to be executed after the added instruction(s). (This instruction was replaced by the iinstruction keyed in at step 3.)

8.Press gi followed by two digits that specify the second line following the point at which the new instruction(s) are being added. This i instruction will cause program execution to branch back to the proper line within the original program.

Example: Continuing with the preceding example, suppose incomes less than or equal to $7,500 were not to be taxed. You could modify the program to check for this condition and stop at line 00, displaying the original income keyed in, by

storing 7,500 in register R3 and adding the following instructions between lines 00 and 01: :3~gogi00. Since there are more than four instructions

between (and including) the first line to be executed after the added instructions (line 01) and the last line you keyed into program memory (line 10), it will require fewer keystrokes to add the new instructions by branching than to add them by replacement.

Keystrokes Display

fs 00-

gi.00 00-

gi1201- 43, 33
gi.10 10-

gi00

11- 43, 33

Sets calculator to Program mode.

Sets calculator to program line immediately preceding point at which new instructions are being added. (In this particular example, this step could have been skipped since calculator was already set at the proper program line.)

12Branches to program line 12, the second line after last line of program.

30Sets calculator to last line of program so that i00 instruction keyed in next will be stored in first line following program.

00Ensures that i00 instruction follows program.

File name: hp 12c_user's guide_English_HDPMBF12E44

Page: 117 of 209

Printered Date: 2005/7/29

Dimension: 14.8 cm x 21 cm