HP HP-11C

212 Section 11: Programming Techniques
the integer portion is always greater than zero, the step
immediately following [ISG] is always skipped. For this reason a
dummy step, in this case, occupies that spot.
Stepping through the program will illustrate the subroutine’s
function.
Instructions First Execution Second Execution
4
(sTo](1)
0
[Fe[Jo
[Re()2
(GSB]9 |
> (rou)s
[Fel(3
(GS8]9
> [Rel)9
I=56 I=6
Skipped. Skipped.
(ReL]((i)) Recalls Rs. Recalls Rg.
R, XRg R3XRg
RoXR,XRg Rg X R 3 XRg
0+RyXR,XRg Adds to previous total.
(s10]O Stores total in Ry, Stores new total in Ry,
(g][R
The space savings is clear. Four steps would have been repeated six
times, a total of twenty-four steps. The subroutine condensed this
to ten (including 4 (1) and excluding 0 which would have
been performed anyway).
Data Input
In writing a program, once you have decided on what data your
program needs, you must then decide on how it will be stored.
Indeed, there are several options depending on the space you have
and the number of inputs to be stored.