what does this line do?

[afflictedd2]

Hi everyone,

I am not sure what this line is doing...


#define VECTOR_BASE 0xBFC0
#define SWIV (*(volatile int *)(VECTOR_BASE + 0x36)) /* SWI */

This is what I'm guessing it does. It takes the address VECTOR_BASE then adds 0x36 to that address and arrives at another adress which is then defined as SWIV. I don't understand why all that casting is necessary?

Would this also accomplish the same?

#define SWIV (*(unsigned char *)(VECTOR_BASE + 0x36)) /* SWI */

Any help appreciated,
Ted.

[kryptkat]

Would this also accomplish the same?

no. one is volatile int * and the other is unsigned char *.
i do not see why vector base was declared twice.

[MK27]

SWIV is a function pointer. VECTOR_BASE is not an address, it's just an integer value.

i do not see why vector base was declared twice.

It wasn't.

[afflictedd2]

SWIV is a function pointer. VECTOR_BASE is not an address, it's just an integer value.



It wasn't.

Thank you so much, that shed some light into the problem.. so if that's a function pointer.. then that is the interrupt handler hmmmmm.

[Adak]

I believe you want an int for an interrupt.