Option

As a general option to any lab that prints a message, write the following PROC and use it:

• PROC: center
• input: line to print on, address of string, & length of string
• output: nothing
• effect: centers the string on the line specified

Hint: Use the shr instruction (see section 6.3.5 under BT) as a quick divide by 2 for your centering.

This option is worth Level 1.5 the first time you use it. For each of the next two uses, you can get Level 0.5 more. After that, I'll assume you've mastered the use of your new PROC and don't need further credit.

(That does not mean that you cannot use it more than three times. In fact, it can be used to great benefit by centering messages on line 24 of the screen where they are visible but don't obscure your main interface at the top of the screen. If you do this option, you should use it where-ever possible. But you can only claim credit on three of those uses.)