Figure 2-2. Sample Program Listing - HP 64700 Series User Manual

Cmdline - as68k -Lh anly.s
Line Address
1
2
3
4 00000000 2E7C 0000 01FC
5
6
7
8
9
10
11 00000006 2241
12 00000008 2200
13
14
15
16 0000000A 6100 0044
17
18
19
20
21
22 0000000E 0801 0001
23 00000012 6700 0006
24 00000016 6000 000E
25 0000001A 0801 0000
26 0000001E 6700 0012
27 00000022 6000 0014
28 00000026 0801 0000
29 0000002A 6700 0012
30 0000002E 6000 0014
31
32
33
34
35
36 00000032 6100 0016
37 00000036 60CE
38 00000038 6100 0010
39 0000003C 60C8
40 0000003E 6100 000A
41 00000042 60C2
42 00000044 6100 0004
43 00000048 60BC
44
45
46
47
48
49 0000004A 1340 0000
50 0000004E 4E75
51
52
53
54
55
56 00000050 2039 0000 0100
2-4 Getting Started
R START
*********************************************
* The next two instructions move the second
* previous random number into A1 (offset to
* RESULTS area, and the previous random
* number into D1.
*********************************************
AGAIN
*********************************************
* RAND returns random number in D0.
*********************************************
*********************************************
* The following instructions determine which
* caller calls WRITE_NUMBER (depends on last
* two bits of the previous random number).
*********************************************
ZERO_ONE
TWO_THREE
*********************************************
* The WRITE_NUMBER routine is called from
* four different places.
* repeated after the subroutine return.
*********************************************
CALLER_0
CALLER_1
CALLER_2
CALLER_3
*********************************************
* The WRITE_NUMBER routine writes the random
* number to the RESULTS area. The second
* previous number is the offset in this area.
*********************************************
R WRITE_NUMBER
*********************************************
* The RAND routine generates a pseudo-random
* number from 0-0FFH, and leaves the result
* in D0.
*********************************************
R RAND

Figure 2-2. Sample Program Listing

XDEF START,AGAIN
XDEF RESULTS,RAND_SEED
SECT PROG,,C
MOVE.L #STACK,A7
MOVE.L D1,A1
MOVE.L D0,D1
BSR RAND
BTST #1,D1
BEQ ZERO_ONE
BRA TWO_THREE
BTST #0,D1
BEQ CALLER_0
BRA CALLER_1
BTST #0,D1
BEQ CALLER_2
BRA CALLER_3
The program is
BSR WRITE_NUMBER
BRA AGAIN
BSR WRITE_NUMBER
BRA AGAIN
BSR WRITE_NUMBER
BRA AGAIN
BSR WRITE_NUMBER
BRA AGAIN
MOVE.B D0,RESULTS(A1)
RTS
MOVE.L RAND_SEED,D0