[avr-gcc-list] External interrupt assembler routine - how?

[Thomas Rehm]

Hi folks,

I want to declare a routine in an external assembler source as an interrupt,
because I want to get rid off the overhead which avr-gcc involves, when an
Interrupt is declared via the AVR-GCC Interrupt API.
Too, I want to reserve some registers for only use by this routine.

Up to now, I found only infos about inline assembler and how to link external
assembling code - but neither how to get an interrupt pointer to my routine
nor how to reserve registers without pushed and popped by the compiler.

Is there any way?

thanks,
Tom.