Re: [avr-gcc-list] generic queue library for AVR GCC?

[gouy yann]

Hi,

I have a question concerning the other bits of SREG.

Saving it before the cli opcode and restoring it at
the end of your critical section is quite nice, but
you seem only interested in preserving the I-bit, what
about the other bits?
Is GCC clever enough to handle them correctly?

best regards.
   Yann

 --- Richard Urwin <address@hidden> a écrit :

> On Monday 15 Nov 2004 11:33 pm, Bruce D. Lightner
> wrote:
> > How about this...
> >
> >      #include <avr/io.h>
> >      #include <avr/interrupt.h>
> >      #include <inttypes.h>
> >      #define begin_critical_section()  SREG; cli()
> >      #define end_critical_section(val) SREG = val
> >      ....
> >      {
> >          unsigned char sreg =
> begin_critical_section();
> >          sm_qin = sm_qout = 0;   // reset queue
> pointers
> >          end_critical_section(sreg);
> >      }
> >
> > This gets you the same, optimally efficient AVR
> code.
> 
> Another option:
> 
> >      #define begin_critical_section() {unsigned
> char sreg = SREG; cli()
> >      #define end_critical_section(val) SREG =
> val;}
> >      ....
> >      {
> >          begin_critical_section();
> >          sm_qin = sm_qout = 0;   // reset queue
> pointers
> >          end_critical_section(sreg);
> >      }
> 
> That will give a C error if you don't match the
> calls up, but requires both
> calls to be at the same block level.
> 
> -- 
> Richard Urwin
> 
> _______________________________________________
> avr-gcc-list mailing list
> address@hidden
> http://www.avr1.org/mailman/listinfo/avr-gcc-list
>  

=====



        

        
                
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