Advanced Assembly Programming - The HCS12/9S12: An Introduction to Software and Hardware Interfacing - page 182

Solution: The logic structure of the program is as follows:
Step 1
Output the message “The prime numbers between 1000 and 2000 are as follows:”.
Step 2
For every number between 1000 and 2000, do the following:
1. Call the PrimeTest() subroutine to see if it is a prime.
2. Output the number (call printf() ) if it is a prime.
3. If there are already eight prime numbers in the current line, then also output a carry
return.
The assembly program is as follows:
CR equ $0D

LF equ $0A

upper equ 2000 ; upper limit for testing prime

lower equ 1000 ; lower limit for testing prime

printf equ $EE88 ; location where the address of printf() is stored

org $1000

out_buf ds.b 10

PRIcnt ds.b 1 ; prime number count

k ds.b 2

tmp ds.b 2

org $1500

start ldx #upper

stx tmp

pshx

ldx #lower

stx k ; initialize k to 1000 for prime testing

pshx

ldd #form0

jsr [printf,PCR]

leas 4,sp

clr PRIcnt

again ldd k

cpd #upper

bhi Pstop ; stop when k is greater than upper

pshd

ldd #0

pshd

jsr primetest ; test if k is prime

leas 4,sp ; deallocate space used by outgoing parameters

tsta

beq next_k ; test next integer if k is not prime

inc PRIcnt ; increment the prime count

ldd k

pshd

ldd #form1

jsr [printf,PCR] ; output k

leas 2,sp