101
Section 9
Subroutines
When the same
set of instructions needs to be used at more than one point
in a program, memory space can be conserved by storing those instructions
as a single subroutine.
The Mechanics
Go To Subroutine and Return
The
G
(
go to subroutine
)
instruction is executed in the same way as the
t
branch, with one major difference: it establishes a
pending return
condition.
G
label,
like
t
label,
*
transfers program execution to the
line with the corresponding label (
A
to
E
, 0 to 9 or .0 to .9). However,
execution then continues
until the first subsequent
n
instruction is
encountered –
at
which point execution
transfers back
to the instruction
immediately following the last
G
instruction, and continues on from
there.
Subroutine Execution
´bA
´b.1
G.1
|n
|n
END
RETURN
Execution transfers to line 000
and halts.
Execution transfers back to
original routine after
G.1
*
A
G
or
t
instruction followed by a
letter
label is an abbreviated key sequence (no
´
necessary). Abbreviated key sequences are explained on page 78
.
Summary of Contents for HP-15C
Page 1: ...HP 15C Owner s Handbook HP Part Number 00015 90001 Edition 2 4 Sep 2011 ...
Page 17: ...Part l HP 15C Fundamentals ...
Page 64: ......
Page 65: ...Part ll HP 15C Programming ...
Page 118: ...118 ...