ColdFire CVS Build Error with 4.0.0

[Pavel Pisa]

>>fails with a gcc error:
>>
>>'_VBR' has an incomplete type'
>>
>>The pertinent code from /cpukit/score/cpu/m68k/rtems/score/m68k.h is
>>shown below.  The asterisked line appears to be where the problem occurs.
>>
>>#elif ( M68K_COLDFIRE_ARCH == 1 )
>>extern uint32_t                     _VBR[];
>>#define m68k_get_vbr( _vbr ) _vbr = _VBR
>>
>>#define m68k_set_vbr( vbr ) \
>>  do { \
>>    asm volatile ( "movec   %0,%%vbr " : : "r" (vbr)); \
>>***    _VBR = (void *)vbr; \
>>  } while(0)
>>
>>CVS indicates that _VBR was changed fairly recently from
>>void* _VBR;
>>to
>>uint32_t   _VBR[];

Hello Joel and others,

I do not know, if this is of some value, but recent
Linux-2.6 kernels use next macros

#define SET_VBR(x) \
        __asm__ __volatile__ (" movec %0,%/vbr" : : "r" (x));

#define GET_VBR(x) \
        __asm__ __volatile__ (" movec %/vbr, %0" : "=g" (x) : );

I use '%/' combination in one of my system-less projects
for ages and it works well. So may it be, that it is preffered
GAS coding.

But I see other fundamental problem, you are trying to
set address of static array or setup full contents of
such array with open length. So this has to fail.

This

--------------------------------
uint32_t   _VBR;
_VBR = vbr;
--------------------------------

or that

--------------------------------
uint32_t   *_VBR;
_VBR = (uint32_t*)vbr;
--------------------------------

or even this 

--------------------------------
extern uint32_t   _VBR[];
#define m68k_set_vbr( vbr_ignored ) \
  do { \
    asm volatile ( "movec   %0,%%vbr " : : "r" (_VBR)); \
  } while(0)

...
/*in some .c file*/
uint32_t   _VBR[256];
--------------------------------

Is corrects. It seems that it is similar conception change
of address to static array which has broken MX1 ARM setup
before some time.

Best wishes

                Pavel Pisa