Parallax BASIC Stamp 2e, Programming Manual

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RETURN - BASIC Stamp Command Reference
Page 266
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BASIC Stamp Programming Manual 2.0b
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www.parallaxinc.com
this time) and because there wasn't a previous place to return to, the
BASIC Stamp will start the entire program over again. This would cause
an endless loop. The important thing to remember here is to always make
sure your program doesn't allow itself to "fall into" a subroutine.
Demo Program (RETURN.bs2)
' This program demonstrates a potential bug caused by allowing a program to 'fall into' a
' subroutine. The program was intented to indicate that it is "Starting...", then
' 'Executing Subroutine', then 'Returned...' from the subroutine and stop. Since we
' left out the END command (indicated in the comments), the program then falls into the
' subroutine, displays 'Executing..." again and then RETURNs to the start of the program
' and runs continuously in an endless loop.
'{$STAMP BS2} 'STAMP directive (specifies a BS2)
DEBUG "Starting Program",CR 'Indicate the start of the program
Main:
PAUSE 1000
GOSUB DemoSub 'Call the subroutine
PAUSE 1000
DEBUG "Returned from Subroutine", CR 'Indicate the return from the subroutine
PAUSE 1000
'<-- Forgot to put an 'END' command here
DemoSub:
DEBUG " Executing Subroutine", CR 'Indicate the execution of the subroutine
RETURN
1 2
e
2
sx
2
p
2
NOTE: This is written for the BS2
but can be used for the BS1, BS2e,
BS2sx and BS2p also. Locate the
proper source code file or modify
the STAMP directive before
downloading to the BS1, BS2e,
BS2sx or BS2p.