Re: [avr-libc-dev] Deprecation policy [was: Re: [RFC][PATCH] Deprecate inb / outb.]

[Dmitry K.]

16 Jun 2003 06:18 Joerg Wunsch wrote:
> Basically, it's now no longer (easily) possible to use one
> of the SFRs as the target of an inline asm statement anyway (see bug
> ID #2233, we need to update our inline asm docs accordingly).

Examples of SFRs usage:

//#define _SFR_ASM_COMPAT  1    /* needed for second example only       */

#include <avr/io.h>

/* Examples of SFRs as the target of an inline asm statements.
   For qualitative realization it is necessary to add check:
        if (__builtin_constant_p((port)))
 */
#define cbi_atomic(port,bit)    do {                    \
    if (_SFR_IO_ADDR(port) < 0x20) {                    \
        asm volatile (                                  \
            "cbi  %0,%1"                                \
            :                                           \
            : "I"(_SFR_IO_ADDR(port)),                  \
              "I"((unsigned char)(bit)) );              \
    } else {                                            \
        unsigned char __tmp;                            \
        asm volatile (                                  \
            "in   __tmp_reg__,__SREG__  \n\t"           \
            "cli                        \n\t"           \
            "in   %0,%1                 \n\t"           \
            "andi %0,%2                 \n\t"           \
            "out  __SREG__,__tmp_reg__  \n\t"           \
            "out  %1,%0                 "               \
            : "=d"(__tmp)                               \
            : "I"(_SFR_IO_ADDR(port)),                  \
              "M"(0377 & ~(1 << (bit))) );              \
    }                                                   \
} while (0)

/* Next definitions for insertion SFRs to body inline asm       */
#define _v(s)   _s(s)
#define _s(s)   #s

void foo (void)
{
    /* Examples of SFRs as the target of an inline asm statements       */
    cbi_atomic(PORTB, 2);
    cbi_atomic(MCUCR, SE);

    /* Example of usage SFRs in body of an inline asm - more readeble   */
#if _SFR_ASM_COMPAT             /* SFRs as simple numbers needed        */
    asm volatile (
        "out    "_v(_SFR_IO_ADDR(PORTB))",__zero_reg__"
        :: );
#endif
}