Does CLEAR Command clear return adrress of a subroutine?

[skimask]

On 14 or lesser bit devices (e.g., 16F or lesser), you cannot clear the Stack (it is a circular buffer and does not reside in program or data space).

I'd almost bet money that there's an undocumented instruction that handles POP's on the 14 bit types...but you'd figure somebody would've found it by now.

[Acetronics2]

Hi, Sayzer

I didn't look at it very closely ...

but I feel you can find your solution Here :

http://www.pbpgroup.com/modules/wfse...p?articleid=14

and once more ...

Thanks to Whom ????

D.A.R.R.E.L. !!!! ..........

Alain

[paul borgmeier]

Hi, Sayzer

I didn't look at it very closely ...

but I feel you can find your solution Here :

http://www.pbpgroup.com/modules/wfse...p?articleid=14

and once more ...

Thanks to Whom ????

D.A.R.R.E.L. !!!! ..........

Alain

Darrel's clever method for the 16F type PICs creates a software stack - the real "stack" is not in program or data space and cannot be accessed (unless there is a back door that nobody knows about as Ski suggested)

I guess that SAYZER could create a software stack (as Alain is suggesting) and then manipulate it as needed? SAYZER, what are you trying to do and with what family of PIC?

[Acetronics2]

Hi, Paul

There's also something Doable ( depends on use ...) :


A GOSUB loads an address you can choose in the stack ...

if ending the SUB with a GOTO instead of a RETURN ... This address will stay as the new "return", "retfie" ... address.

That's used with the "RESUME Label" of PbP ...

I do not think "clearing" the stack would be really useful ... as a stack containing zeros will cause the device to reset ONLY its program on the first "return or so" met ...

Alain

[sayzer]

As Alain mentioned, there are potential side effects If I start playing directly with the registers.

Instead now, I am using flags being set to zero before going to a subroutine, and set the flags if something inside the subroutine is used.

Then at the end of the subroutine(s), I am using a kind of select case with "GOTO".

This way, I don't have any "return" address to care for.


This is a little code eating though; but a lot safer.

-------------------

[skimask]

As Alain mentioned, there are potential side effects If I start playing directly with the registers.
Instead now, I am using flags being set to zero before going to a subroutine, and set the flags if something inside the subroutine is used.
Then at the end of the subroutine(s), I am using a kind of select case with "GOTO".
This way, I don't have any "return" address to care for.
This is a little code eating though; but a lot safer.
-------------------

How about something like this:

main:
code....code...code...
addrreturn = 1
goto subroutine

return1:
addrreturn = 2
goto subroutine

return2:
addrreturn = 0
goto main

subroutine:
code....code....code
branch addrreturn , [ return1 , return2, return3.................]

Set your branch return location parameter, jump to the generic subroutine, branch back to wherever it came from. No calls, no gosubs, and so on...

[paul borgmeier]

Instead now, I am using flags being set to zero before going to a subroutine, and set the flags if something inside the subroutine is used.

Then at the end of the subroutine(s), I am using a kind of select case with "GOTO".

This way, I don't have any "return" address to care for.

Hi SAYZER,

I do not get what you mean by "return" address care ... why can't you just match each "gosub" with a "return" and let PBP do the work.

[sayzer]

In the code, I jump from locations to locations really very fequently.

I am having a lot of return addresses.
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