[RESOLVED] void pointer to interrupt function

Hi All

I am working with Hi-Tech's HC51-Lite compiler...its a nightmare.

I am trying to assign an ISR to run on a certain interrupt vector.
The Hi-Tech manual recommends a couple techniques only one of which works in my version: using inline asm code. The asm code means I need obtain a pointer to the ISR so I can place this in the ACC and thus reference it in the asm section.
My current C code to do this is:

Code:

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// ISR name= interrupt void ext1isr (void)
        void (*pisr)(void);
        pisr = &ext1isr;  // Line 23
        ACC = ((int*)pisr);  // Line 24

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But the compiler gives me errors:

Error : 23 undefined identifier "ext1isr"
Warning : 23 illegal conversion between pointer types
Warning : 24 illegal conversion of pointer to integer

Frankly void pointers and pointers to functions are outside my level of knowledge so any help much appreciated.
Thanks

EDIT: just tried: interrupt voide (*pisr) (void); but no change

I have never used that compiler but I'll try to assist the best I can.

What is ext1isr in this context?

You check ext1isr variable, it's not been declared in code scope.

@Athiest

Quote:

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Originally Posted by wolf99

Code:

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// ISR name= interrupt void ext1isr (void)

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ext1isr is the function. Im trying to make a pointer to a function.

So I have the rest of the pointer manipulation working bar trying to assign the functions address to the pointer.
In Keil C (and ANSI C AFAIK) the code would be this:

Code:

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pIsr = &functionName;

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Which is what seems to be throwing the only error that functionName is an undefined identifier....
I placed the ISR function above the main() in the file and the error leaves but is replaced by a warning: "redundant "&" applied to function" which makes me think that what is happening here is that the program is actually calling the function and expecting a variable to be returned that will then be placed in the variable pISR, some thing like if I had written:

Code:

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int x = add(5,5) // expect x = 10

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*sigh*

Is the method defined in the same code file as the containing the code of your first post? Have you placed a function declaration at the top of your code?

Code:

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void ext1isr(void);

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You probably already know this, but if you omit this declaration, the order of which the methods are written suddenly becomes important, because you can not refer to a method defined further down in your source code.

Quote:

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Originally Posted by wolf99

I placed the ISR function above the main() in the file...

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With the ISR function being ext1isr, and main containing the code snippet from the first post? Have you tried simply removing the ampersand from your assignment? I just tried with gcc and it allows function pointer assignment to be done both with and without the ampersand. Perhaps your compiler only supports the latter.

Code:

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pIsr = functionName;

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Hi Athiest
Thanks, I had neglected to declare the isr *facepalm*

So Ive removed the & and the warning has gone...
... checking in memory view... and yes the right values are in the DPTR

Many Thanks!

(now I just need to get my LJUMP right..oh I see youve answered that t0o! coolio!)

Great! :)