Motorola Axiom CMD11E1 Uživatelská příručka stáhnout pdf (Strana 64)

64 CHAPTER 5. TABLES

Exercise: Type the above program, assemble it, transfer the S19 ﬁle to the

68HC11, and run the program with CALL 2100. When the program starts, type

the following text Pack my box with five dozen liquor jugs.

Exercise: The lookup program aﬀects the X and B registers. Modify the func-

tion so that the function initially stores these two registers in the stack, and

restores them before returning. Verify that the program works correctly.

Exercise: Modify the program by adding another table, the table of symmetric

characters: AHIMOTUVWXYimnouvwxy. The program should, in addition to checking

to see if a character is a vowel, it should also check to see if it is a symmetric

character. Run the program and enter the following text: Axiomboard. You

should get an output similar to the following:

done

>c 2100

=====================================

Lab on using Tables

Name: _____________________

This program is an infinite loop!

Hit the reset button to quit

=====================================

A is a vowel and is a symmetric character

x is not a vowel and is a symmetric character

i is a vowel and is a symmetric character

o is a vowel and is a symmetric character

m is not a vowel and is a symmetric character

b is not a vowel and is not a symmetric character

o is a vowel and is a symmetric character

a is a vowel and is not a symmetric character

r is not a vowel and is not a symmetric character

d is not a vowel and is not a symmetric character

5.5.2 Input with validation

Another use of the table lookup is to validate input from the user. Suppose we

want the user to enter a social security number. In this case, we want to make sure

1 2 ... 59 60 61 62 63 64 65 66 67 68 69 ... 100 101

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Motorola Axiom CMD11E1 Uživatelská příručka Strana 64