On Wed, 2009-04-29 at 17:39 -0700, Ian Lance Taylor wrote: > John Farmer <news02@xxxxxxxxxxx> writes: > > > As far as I have been able to find out it is not possible to write an > > interrupt function where its address is added to a selectable position in > > the vector table automatically by the compiler/linker. Just to be certain > > would that be right? > > Seems like it could be done pretty easily with a bit of assembly code or > with some linker script magic. > > > Would I be correct in thinking that a normal function could be used as an > > ISR in which case I do not need to use the __attribute__((interrupt)) at > > all? If this is the case what is this attribute used for? > > It depends on the details of your platform. For ARM, the different > types of interrupt routines return to their caller in different ways, so > they can not be replaced by a regular function (though I think they > could be replaced by an assembly code wrapper). > > Ian It depends on your ARM chip. For Cortex-m3 (rev 2 or later, IIRC[1]) any function with a prototype "void func(void)" can be used as an ISR since the hardware will do all the register stacking for you. R. [1] It works on earlier revs too, provided you don't have variadic functions.
