10-14   Programming
On the TI
.
80, any program can be called from another program as a subroutine.
Enter the name of the program to use as a subroutine on a line by itself.
To call one program from another, begin on a blank line in the
program editor and do one of the following.
¦
Press 
K
 
6
 to display the 
PRGM EXEC
 menu, and
select the name of the program. 
PRGM_
 and the name are
copied to the cursor location.
¦
Select 
PRGM_
 from the 
PRGM CTL
 menu and then type
the letters of the 
programname
.
PRGM_
programname
When this instruction is encountered during program
execution, the next command that the program executes is the
first command in the second program. Execution continues
with the subsequent command in the first program when it
encounters either a 
RETURN
 instruction or when the implied
RETURN
 at the end of the called program is encountered.
Variables are global.
A label used with 
GOTO
 and 
LBL
 is local to the program in
which it is located. A label in one program is not “known” by
another program. You cannot use 
GOTO
 to branch to a label
in another program.
RETURN
 exits a subroutine and returns to the calling
program, even if encountered within nested loops.
Calling Other Programs
Calling a
Program from
Another
Program
Notes about
Calling
Programs