Re: [avr-gcc-list] Avoid register saving

[Artur Lipowski]

Filipe Campos wrote:
> Hi.
> In some application the save register can be good.
> But if You write a little RTOS Kernell, the kernell shall do this, not the
> compiler. It´s worst if You have a little RAM to use.
I'm afraid that you cannot avoid writing core ISR handler in assembler 
in such cace.

> 
> But You give a good idea, How the ISR can be writen in ASM and than compiled
> by the AVR-GCC ?
#include <avr/io.h>
        .global SIG_OVERFLOW0
SIG_OVERFLOW0:
        push    __tmp_reg__
        in      __tmp_reg__, _SFR_IO_ADDR(SREG)
        push    work1
.................................
        pop     work1
        out     _SFR_IO_ADDR(SREG), __tmp_reg__
        pop     __tmp_reg__
        reti

Put above source into file with .S suffix and thats all.

If your system has problems with cases of letters in fineames then you 
can use "-x assembler-with-cpp" as an option for the GCC.


Regards,
-- 
Artur Lipowski

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