ColdFire CVS Build Error - PR 803

[Pavel Pisa]

On Wednesday 01 June 2005 23:47, Brett Swimley wrote:
> I'll look into it and help where I can.
>
>  My suspicion on the uC5282 is that it's not using that particular
> macro.  I had it compile as well.
>
> Brett

Hello Brett and others,

I do not use ColdFire now, but I like m68k architecture
and that is why I have tried to respond to the problem report
already.

I have glimpsed to PR 803 solution, but I am convinced
that even more damage has slipperred-in.

The _VBR variable is used in the two distinct and incompatible
meanings now.

The _VBR (as understand by more linkcmds and !M68K_HAS_VBR architectures)
is start address of the static array of interrupt vectors.
You have overload that meaning by changing of _VBR declaration
and using of it as the variable holding pointer to the
interrupt table.

----------------------------------------------------------------

extern void*                     _VBR;

----------------------------------------------------------------

#elif ( M68K_COLDFIRE_ARCH == 1 )
extern void*                     _VBR;
#define m68k_get_vbr( _vbr ) _vbr = &_VBR
                             /* !!! ^- Error there !!! */

#define m68k_set_vbr( _vbr ) \
  do { \
    asm volatile ( "movec   %0,%%vbr " : : "r" (_vbr)); \
    _VBR = (void *)_vbr; \
  } while(0)

#else

----------------------------------------------------------------

You have inconsistency between 68000 meaning and ColdFire
meaning and even internal inconsistency between ColdFire macros.
The ColdFire version of the m68k_set_vbr macro stores vector
table address in the first vector location of _VBR area provided
by linkcmds.

I would suggest to separate _VBR static array meaning from VBR register
shadow and correct m68k_get_vbr.

----------------------------------------------------------------

/* static array allocated for vector table by BSP's linkcmds */
extern uint32_t                  _VBR[];

/* shadow store for the VBR register readback for ColdFire architecture */
extern void*                     _VBR_REG_SHADOW;

----------------------------------------------------------------

#elif ( M68K_COLDFIRE_ARCH == 1 )
/*extern ???*/ void*             _VBR_REG_SHADOW;
#define m68k_get_vbr( _vbr ) do{ _vbr = _VBR_REG_SHADOW; } while(0)

#define m68k_set_vbr( _vbr ) \
  do { \
    asm volatile ( "movec   %0,%%vbr " : : "r" (_vbr)); \
    _VBR_REG_SHADOW = (void *)_vbr; \
  } while(0)

#else

----------------------------------------------------------------

There is even one more thing to solve in the code above.
If you preserve "extern" word there, you have to
declare _VBR_REG_SHADOW variable in the some of score/cpu/m68k
*.c files as well.

Best wishes

                Pavel Pisa
        e-mail: pisa at cmp.felk.cvut.cz
        www:    http://cmp.felk.cvut.cz/~pisa
        work:   http://www.pikron.com