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

[Bruce D. Lightner]

E. Weddington wrote:

> I agree with Bruce's method; it's better in that it preserves the 
> original state of the interrupt flag.

I believe that the "push/pop" method did as well...

> The push/pop is not required, and probably wasteful.
>
> Though you don't have to do it in inline assembly. It can be done all in C:
>
> #include <avr/io.h>
> #include <avr/interrupt.h>
> #include <inttypes.h>
> ....
> {
>    uint8_t sreg = SREG;
>    cli();
>    sm_qin = sm_qout = 0;  // reset queue pointers.
>    SREG = sreg;  }

Yeah.  I like yours better.  The resultant AVR code is identical.

I've got to "get onboard" with the "new" gcc 3.x AVR I/O syntax.
I still have a number of active mixed AVR assembly/avr-gcc
projects, which only work with the gcc 2.95 I/O definitions, so
I guess I gravitate to inline assembly more often than I probably
should. :-)

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.

Best regards,

Bruce

--
 Bruce D. Lightner
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