HP 15c - Manual (Page 78)

78 Section 6: Programming Basics
corresponding label. If need be, the search will wrap around at the end of
program memory and continue at line 000. When it encounters an
appropriate label, the search stops and execution begins.
If a label is encountered as part of a running program, it has no effect, that
is, execution simply continues. Therefore, you can label a subordinate
routine within a program (more on subroutines in section 9).
Since the calculator searches in only one direction from its present position,
it is possible (though not advisable) to use duplicate program labels.
Execution will begin at the first appropriately labeled line encountered.
If an ´ A
entry starts the search
for ―A‖ here,
it then proceeds downward through
memory, wraps around to line 000,
and stops at label ―A‖. Execution then
starts and continues (ignoring any
other labels) until a halt instruction.
000-
(stop)
´bA
´b3
¦
end of memory
Unexpected Program Stops
Pressing Any Key. Pressing any key will halt program execution. It will
not halt in the middle of an operation. This instruction will be completed
before the program stops.
Error Stops. Program execution is immediately halted when the calculator
attempts an improper operation that results in an
Error display.
To see the line number and keycode of the error-causing instruction (the
line at which the program stopped), press any one key to remove the
Error
message, then switch to Program mode.
If the display is flashing when a program stops, an overflow condition exists
(page 61). Press − =,
or | " 9 to stop the blinking.
Abbreviated Key Sequences
In certain cases, an ´ prefix you might expect to include in a key
sequence is not needed. The rule for using an abbreviated key sequence is:
the ´ prefix key is unnecessary after any other prefix key. (Page 19
contains a list of prefix keys.)