[Icc-avr] Bootloader

[David Brown]

Bengt Ragnemalm wrote:
> Is it possible for the normal program to access functions in the 
> bootloader (to save space)? If that is so, how do I do it in C?
> 
>  
> 
> Best regards
> 
> Bengt
> 

You would want to set up a table of functions in the boot program such as:

typedef void (*fvoid)(void);

extern int foo(void);
extern void bar(int a, int b);

const fvoid funcTable[] = {
	(fvoid) foo,
	(fvoid) bar
}

You need to either fix it at a specific address, or to find it's address 
and compile that into the main program:

typedef void (*fvoid)(void);
#define funcTableAddress 0x1000		// Or whatever
#define funcTable(n) (((fvoid*) funcTableAddress)[n])

#define foo() ((int (*)(void)) funcTable(0))()
#define bar(a, b) ((void (*)(int, int)) funcTable(1))(a, b)

Then you can use foo() and bar(a, b) as though they were normal functions.

mvh.,

David