[avr-libc-dev] [bug #14616] definition of sei() in interrupts.h is faulty

[anonymous]

URL:
  <http://savannah.nongnu.org/bugs/?func=detailitem&item_id=14616>

                 Summary: definition of sei() in interrupts.h is faulty
                 Project: AVR C Runtime Library
            Submitted by: None
            Submitted on: Do 22.09.2005 um 14:59
                Category: Header
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
                 Privacy: Public
             Assigned to: None
        Percent Complete: 0%
        Originator Email: address@hidden
             Open/Closed: Open

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Details:

Hi,

we need to change the definition of the sei macro in interrupts.h such that
it reads

#define sei()  __asm__ __volatile__ ("sei" : : : "memory")

instead of 

#define sei()  __asm__ __volatile__ ("sei" ::)

I just had a situation where protecting an assignment by;

cli ();
uint16_t_variable_in_memory = value;
sei ();

did not work since avr-gcc did interchange the assignment and the sei()
because it did not know anything on the possible side-effects of sei()!

For the same reason I think that we should add a macro

#define write_sreg(value)  __asm__ __volatile__ ("out __SREG__,%0" : : "r"
(value) : "memory")

that signalizes gcc that writing the SREG could have possible side effects on
the memory!

Yours,

Bjoern



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Carbon-Copy List:

CC Address                          | Comment
------------------------------------+-----------------------------
bjoern --PUNKT-- haase --AT-- de --PUNKT-- bosch --PUNKT-- com | Originator
Email




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