Nested Subroutines - HP -32S Owner's Manual

Nested Subroutines
A subroutine can call another subroutine, and that subroutine can call
yet another subroutine. This 'nesting" of subroutines—the calling of a
subroutine within another subroutine—is limited to a stack of subrou
tines seven levels deep (not counting the topmost program level). The
operation of nested subroutines is as shown below:
Main program
(top level)
LBL R
.
LBL B
LBL C
,
LBL D
I
LBL E
XEQ B
I4
XEQ C
XEQ 0
[/
XEQ E
V
SIN
K
3.1416
K
SQRT
IN
RCL R
h
RTN
+
RTN
V
RTN
V
RTN
7
RTN
End of
program
Attempting to execute a subroutine nested more than seven levels
deep causes an XEQ OVERFLOW error.
Example: A Nested Subroutine. The following subroutine, labeled
S, calculates the value of the expression
Vfl2 + b2 + c2 + d2
as part of a larger calculation in a larger program. The subroutine
calls upon another subroutine (a nested subroutine), labeled Q, to do
the repetitive squaring and addition. This keeps the program shorter
than it would be without the subroutine.
92 6: Programming Techniques