ffi.c

gcc的组建

          cif->flags += FFI_TYPE_INT << (FFI_FLAG_BITS * 2);
          break;
        }
    }
  else
    {
      /* FFI_O32 */      
      switch (cif->rtype->type)
        {
        case FFI_TYPE_VOID:
        case FFI_TYPE_STRUCT:
        case FFI_TYPE_FLOAT:
        case FFI_TYPE_DOUBLE:
          cif->flags += cif->rtype->type << (FFI_FLAG_BITS * 2);
          break;

        case FFI_TYPE_SINT64:
        case FFI_TYPE_UINT64:
          cif->flags += FFI_TYPE_UINT64 << (FFI_FLAG_BITS * 2);
          break;
      
        default:
          cif->flags += FFI_TYPE_INT << (FFI_FLAG_BITS * 2);
          break;
        }
    }
#endif

#if _MIPS_SIM == _ABIN32
  /* Set the flags necessary for N32 processing */
  {
    unsigned shift = 0;
    unsigned count = (cif->nargs < 8) ? cif->nargs : 8;
    unsigned index = 0;

    unsigned struct_flags = 0;

    if (cif->rtype->type == FFI_TYPE_STRUCT)
      {
	struct_flags = calc_n32_return_struct_flags(cif->rtype);

	if (struct_flags == 0)
	  {
	    /* This means that the structure is being passed as
	       a hidden argument */

	    shift = FFI_FLAG_BITS;
	    count = (cif->nargs < 7) ? cif->nargs : 7;

	    cif->rstruct_flag = !0;
	  }
	else
	    cif->rstruct_flag = 0;
      }
    else
      cif->rstruct_flag = 0;

    while (count-- > 0)
      {
	switch ((cif->arg_types)[index]->type)
	  {
	  case FFI_TYPE_FLOAT:
	  case FFI_TYPE_DOUBLE:
	    cif->flags += ((cif->arg_types)[index]->type << shift);
	    shift += FFI_FLAG_BITS;
	    break;

	  case FFI_TYPE_STRUCT:
	    cif->flags += calc_n32_struct_flags((cif->arg_types)[index],
						&shift);
	    break;

	  default:
	    shift += FFI_FLAG_BITS;
	  }

	index++;
      }

  /* Set the return type flag */
    switch (cif->rtype->type)
      {
      case FFI_TYPE_STRUCT:
	{
	  if (struct_flags == 0)
	    {
	      /* The structure is returned through a hidden
		 first argument. Do nothing, 'cause FFI_TYPE_VOID 
		 is 0 */
	    }
	  else
	    {
	      /* The structure is returned via some tricky
		 mechanism */
	      cif->flags += FFI_TYPE_STRUCT << (FFI_FLAG_BITS * 8);
	      cif->flags += struct_flags << (4 + (FFI_FLAG_BITS * 8));
	    }
	  break;
	}
      
      case FFI_TYPE_VOID:
	/* Do nothing, 'cause FFI_TYPE_VOID is 0 */
	break;
	
      case FFI_TYPE_FLOAT:
      case FFI_TYPE_DOUBLE:
	cif->flags += cif->rtype->type << (FFI_FLAG_BITS * 8);
	break;
	
      default:
	cif->flags += FFI_TYPE_INT << (FFI_FLAG_BITS * 8);
	break;
      }
  }
#endif
  
  return FFI_OK;
}

/* Low level routine for calling O32 functions */
extern int ffi_call_O32(void (*)(char *, extended_cif *, int, int), 
			extended_cif *, unsigned, 
			unsigned, unsigned *, void (*)());

/* Low level routine for calling N32 functions */
extern int ffi_call_N32(void (*)(char *, extended_cif *, int, int), 
			extended_cif *, unsigned, 
			unsigned, unsigned *, void (*)());

void ffi_call(ffi_cif *cif, void (*fn)(), void *rvalue, void **avalue)
{
  extended_cif ecif;

  ecif.cif = cif;
  ecif.avalue = avalue;
  
  /* If the return value is a struct and we don't have a return	*/
  /* value address then we need to make one		        */
  
  if ((rvalue == NULL) && 
      (cif->rtype->type == FFI_TYPE_STRUCT))
    ecif.rvalue = alloca(cif->rtype->size);
  else
    ecif.rvalue = rvalue;
    
  switch (cif->abi) 
    {
#if _MIPS_SIM == _ABIO32
    case FFI_O32:
    case FFI_O32_SOFT_FLOAT:
      ffi_call_O32(ffi_prep_args, &ecif, cif->bytes, 
		   cif->flags, ecif.rvalue, fn);
      break;
#endif

#if _MIPS_SIM == _ABIN32
    case FFI_N32:
      ffi_call_N32(ffi_prep_args, &ecif, cif->bytes, 
		   cif->flags, ecif.rvalue, fn);
      break;
#endif

    default:
      FFI_ASSERT(0);
      break;
    }
}

#if FFI_CLOSURES  /* N32 not implemented yet, FFI_CLOSURES not defined */
#if defined(FFI_MIPS_O32)
extern void ffi_closure_O32(void);
#endif /* FFI_MIPS_O32 */

ffi_status
ffi_prep_closure (ffi_closure *closure,
		  ffi_cif *cif,
		  void (*fun)(ffi_cif*,void*,void**,void*),
		  void *user_data)
{
  unsigned int *tramp = (unsigned int *) &closure->tramp[0];
  unsigned int fn;
  unsigned int ctx = (unsigned int) closure;

#if defined(FFI_MIPS_O32)
  FFI_ASSERT(cif->abi == FFI_O32 || cif->abi == FFI_O32_SOFT_FLOAT);
  fn = (unsigned int) ffi_closure_O32;
#else /* FFI_MIPS_N32 */
  FFI_ASSERT(cif->abi == FFI_N32);
  FFI_ASSERT(!"not implemented");
#endif /* FFI_MIPS_O32 */

  tramp[0] = 0x3c190000 | (fn >> 16);     /* lui  $25,high(fn) */
  tramp[1] = 0x37390000 | (fn & 0xffff);  /* ori  $25,low(fn)  */
  tramp[2] = 0x3c080000 | (ctx >> 16);    /* lui  $8,high(ctx) */
  tramp[3] = 0x03200008;                  /* jr   $25          */
  tramp[4] = 0x35080000 | (ctx & 0xffff); /* ori  $8,low(ctx)  */

  closure->cif = cif;
  closure->fun = fun;
  closure->user_data = user_data;

  /* XXX this is available on Linux, but anything else? */
  cacheflush (tramp, FFI_TRAMPOLINE_SIZE, ICACHE);

  return FFI_OK;
}

/*
 * Decodes the arguments to a function, which will be stored on the
 * stack. AR is the pointer to the beginning of the integer arguments
 * (and, depending upon the arguments, some floating-point arguments
 * as well). FPR is a pointer to the area where floating point
 * registers have been saved, if any.
 *
 * RVALUE is the location where the function return value will be
 * stored. CLOSURE is the prepared closure to invoke.
 *
 * This function should only be called from assembly, which is in
 * turn called from a trampoline.
 *
 * Returns the function return type.
 *
 * Based on the similar routine for sparc.
 */
int
ffi_closure_mips_inner_O32 (ffi_closure *closure,
			    void *rvalue, ffi_arg *ar,
			    double *fpr)
{
  ffi_cif *cif;
  void **avaluep;
  ffi_arg *avalue;
  ffi_type **arg_types;
  int i, avn, argn, seen_int;

  cif = closure->cif;
  avalue = alloca (cif->nargs * sizeof (ffi_arg));
  avaluep = alloca (cif->nargs * sizeof (ffi_arg));

  seen_int = (cif->abi == FFI_O32_SOFT_FLOAT);
  argn = 0;

  if ((cif->flags >> (FFI_FLAG_BITS * 2)) == FFI_TYPE_STRUCT)
    {
      rvalue = (void *) ar[0];
      argn = 1;
    }

  i = 0;
  avn = cif->nargs;
  arg_types = cif->arg_types;

  while (i < avn)
    {
      if (i < 2 && !seen_int &&
	  (arg_types[i]->type == FFI_TYPE_FLOAT ||
	   arg_types[i]->type == FFI_TYPE_DOUBLE))
	{
#ifdef __MIPSEB__
	  if (arg_types[i]->type == FFI_TYPE_FLOAT)
	    avaluep[i] = ((char *) &fpr[i]) + sizeof (float);
	  else
#endif
	    avaluep[i] = (char *) &fpr[i];
	}
      else
	{
	  if (arg_types[i]->alignment == 8 && (argn & 0x1))
	    argn++;
	  switch (arg_types[i]->type)
	    {
	      case FFI_TYPE_SINT8:
		avaluep[i] = &avalue[i];
		*(SINT8 *) &avalue[i] = (SINT8) ar[argn];
		break;

	      case FFI_TYPE_UINT8:
		avaluep[i] = &avalue[i];
		*(UINT8 *) &avalue[i] = (UINT8) ar[argn];
		break;
		  
	      case FFI_TYPE_SINT16:
		avaluep[i] = &avalue[i];
		*(SINT16 *) &avalue[i] = (SINT16) ar[argn];
		break;
		  
	      case FFI_TYPE_UINT16:
		avaluep[i] = &avalue[i];
		*(UINT16 *) &avalue[i] = (UINT16) ar[argn];
		break;

	      default:
		avaluep[i] = (char *) &ar[argn];
		break;
	    }
	  seen_int = 1;
	}
      argn += ALIGN(arg_types[i]->size, FFI_SIZEOF_ARG) / FFI_SIZEOF_ARG;
      i++;
    }

  /* Invoke the closure. */
  (closure->fun) (cif, rvalue, avaluep, closure->user_data);

  if (cif->abi == FFI_O32_SOFT_FLOAT)
    {
      switch (cif->rtype->type)
        {
        case FFI_TYPE_FLOAT:
          return FFI_TYPE_INT;
        case FFI_TYPE_DOUBLE:
          return FFI_TYPE_UINT64;
        default:
          return cif->rtype->type;
        }
    }
  else
    {
      return cif->rtype->type;
    }
}

#endif /* FFI_CLOSURES */