Can RESUME replace RETURN in a GOSUB?

[Darrel Taylor]

Hi Peter,

The RESUME command does the same thing as a RETURN, except that it also turns on the GIE (INTCON.7) bit to re-enable Interrupts.   Not a good idea if your program isn't set-up to handle interrupts. And, since it's still a RETURN, it doesn't solve your problem.

However, unlike Visual Basic, the program doesn't have to return from the exact same Subroutine that was called to begin with. You can GOTO another section of code and then RETURN from there.

BADCODE:
SOMEWHERE IN MY CODE:
IF PORTA.1 = 1 THEN GOSUB DOSOMETHING

DOSOMETHING:
    IF PORTB.2 = 1 Then Return
    IF PORTA.5 = 0 Then Return
    IF PORTB.0 = 0 Then DoSomethingElse
GoTo DOSOMETHING 'STAY HERE UNTIL RB2, RA5 OR RB0 DOES SOMETHING

DoSomethingElse:
    ... 
RETURN

Or, if you want it to jump somewhere that doesn't return, you can set a "Flag" in the subroutine, and act on it in the main loop.

FlagBit  VAR  BIT

BADCODE:
SOMEWHERE IN MY CODE:
    FlagBit = 0
    IF PORTA.1 = 1 THEN GOSUB DOSOMETHING
    IF FlagBit = 1 then START
    ...

DOSOMETHING:
    IF PORTB.2 = 1 Then Return
    IF PORTA.5 = 0 Then Return
    IF PORTB.0 = 0 Then FlagBit = 1 : Return
GoTo DOSOMETHING 'STAY HERE UNTIL RB2, RA5 OR RB0 DOES SOMETHING

This way, the RETURN has been satisfied, so you're free to GOTO anywhere.
<br>

[peterdeco1]

Thank you Darrel. I thought
IF PORTB.0 = 0 Then FlagBit = 1 : Return
was the same as
IF PORTB.0 = 0 Then FlagBit = 1
Return
If it is the same, isn't it going to RETURN regardless of PORTB.0 or Flagbit? Does the first statement RETURN only when PORTB.0 = 0? Thank you. -Peter


DOSOMETHING:
IF PORTB.2 = 1 Then Return
IF PORTA.5 = 0 Then Return
IF PORTB.0 = 0 Then FlagBit = 1 : Return
GoTo DOSOMETHING 'STAY HERE UNTIL RB2, RA5 OR RB0 DOES SOMETHING

[Darrel Taylor]

You can have several statements on a single line and they will all be executed ONLY if the IF is true.

IF A = B then C = A : LOW PORTB.0 : PAUSE 100 : RETURN

Which is the same as ...

IF A = B then
&nbsp;&nbsp;&nbsp;&nbsp;C = A
&nbsp;&nbsp;&nbsp;&nbsp;LOW PORTB.0
&nbsp;&nbsp;&nbsp;&nbsp;PAUSE 100
&nbsp;&nbsp;&nbsp;&nbsp;RETURN
ENDIF

HTH

[peterdeco1]

Hi Darrel. You have opened up a whole new way for me to accomplish certain tasks. I migrated from a different basic compiler which doesn't support multiple commands on a single line. Being able to do this solves a lot of problems. - Peter