HP HP-67 - Page 246

242 Using the I-Register for Indirect Control
The use of the {@ instruction lets you select the operations
that are performed upon the number after the main portion of the
program.
By storing 1, 2, or 3 in the I-register depending upon the format of
the seed, the program selects the form of the result after it is
generated by the main portion of the program. Although the program
shown here stops after each result, it would be a simple matter to
create a loop that would iterate several times, increasing the apparent
randomness of the result each time.
To key in the complete program:
Slide the W/PRGM-RUN switch wrrGM [Tl RUN to W/PRGM.
Press Display
m
BEOn 001 31 25 11
=R 002 43
2 Changes nnnn to nn.nn.
8 004 81
1 Places 1 in X-register for
storage in I.
L Jel
0Ee
D
2
Changes
.nnnn
to
nn.nn.
e
2 Places 2 in X-register for
storage in I.
o
o
3 Places 3 in X-register for
storage in I.
e @
o 016 35 33| Stores address of later
operation in I.
Q 017 35 52| Brings nn.nn to
X-register.