How can I read out the PC?

Call a special subroutine that reads the return address off the stack.

I don't wanna use a "call" subroutine!
I just use a "jmp" command. For having the return address I need the actual PC value.
(no label).

You may not wanna calla subroutine but you're gonna hafta calla subroutine to finda outa the value of the program counta.

Stefan

I am not allowed to use a "call" function because I am not allowed to alter the stack pointer (SP). Instead of using the "call" command I want to use a "jmp". Before I perform the jump command I need to have the return address from the program counter, so that I can return back to the source of the jump command. That is like I would use a call function, but without altering the SP!

Are you out of stack space, or did someone give you some arbitrary "don't change the SP" directive ?

You could recova a few bytes from the stack by popping into unused registers.

This sounds like a class project. So, here's a hint. Lookup the $ operator.

Jon

I am not allowed to use a "call" function because I am not allowed to alter the stack pointer (SP).

Huh, "not allowed"? Pray tell: who or what is stopping you?

That restriction seems outright ridiculous. Does "making an omelett without breaking an egg" ring any bell to you?

"I don't wanna use a 'call' subroutine!
I just use a 'jmp' command."

Usa 'call' ta getta PC inta varaibil, den jumpta him!

So far, I have a first solution on my own:

mov r0, #high(return_label)
mov r1, #low(return_label)

ljmp sub_function

return_label:
; any code here

sub_function:
clr a
mov DPH, r0
mov DPL, r1
jmp @a+DPTR 

Hi,
Which language do you talk about?

If ASM:

; somewhere in a program:
MOV DPH,#HIGH(LABEL)
MOV DPL,#LOW(LABEL)
LABEL:

hi,
I want to use a "jmp". ...so that I can return back to the source of the jump command. That is like I would use a call function, but without altering the SP!

Sorry? Why not simple:

; main stream
; ....
JMP MY_TASK ; go to your "subroutine"
L_CONTINUE:
; contunue main stream

MY_TASK:
; your piece of code
JMP L_CONTINUE ; return to main stream

Yes, that should be Assembler :-)
It is maybe a little bit different to the 8051 controller, but quite similar!

Your example is somehow the same that I have!