Motorola Axiom CMD11E1 Guía de usuario descargar pdf (Pagina 25)

2.5. OTHER CONDITIONAL BRANCHES 25

Branch to LOCif A >= MEM

CMPA MEM

BGE LOC *Branch if Greater or Equal

Branch to LOCif A < MEM

CMPA MEM

BLT LOC *Branch if Less Than

2.5.4 An example: HEX2BCD

Consider the problem of converting a number represented in binary to its equiv-

alent representation in BCD. Without going into too much detail, the rule for

numbers between 0 and 99 (two digit numbers) is as follows:

1. For numbers between 0 and 9 (inclusive), no change.

2. For numbers between 10 and 19 (inclusive), add 6.

3. For numbers between 20 and 29 (inclusive), add 12.

4. · · · · · ·

5. For numbers between 90 and 99 (inclusive), add 54.

Without using Loops

Here is a program that takes the value in location $D000, convert it to BCD and

store it in location $D001. First a program that does not use loops. Before running

the program use MM to change the value in location $D000. Recall MM requires

you to enter the value in HEX. So make sure the value you enter is between 00

and 63.

;;;;;;;;;;;;;;;;;;;;;;;;; START OF HEX2BCD ;;;;;;;;;;;;;;;

;

; THIS PROGRAM TAKES THE VALUE IN LOCATION $D000 AND

; CONVERTS IT TO ITS BCD REPRESENTATION AND STORES THE

; RESULT IN LOCATION $D001

;

; THE NUMBER IN LOCATION $D000 SHOULD BE BETWEEN 0 AND 99 ($63)

; NUMBERS BIGGER THAN 99 ARE IGNORED AND LEFT UNCHANGED.

; THE PROGRAM ADDS MULTIPLES OF 6 AS APPROPRIATE

1 2 ... 20 21 22 23 24 25 26 27 28 29 30 ... 100 101

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Motorola Axiom CMD11E1 Guía de usuario Pagina 25