ffi.c

gcc的组建

/* -----------------------------------------------------------------------
   ffi.c
   
   m68k Foreign Function Interface 
   ----------------------------------------------------------------------- */

#include <ffi.h>
#include <ffi_common.h>

#include <stdlib.h>

/* ffi_prep_args is called by the assembly routine once stack space has
   been allocated for the function's arguments.  */

static void *
ffi_prep_args (void *stack, extended_cif *ecif)
{
  unsigned int i;
  void **p_argv;
  char *argp;
  ffi_type **p_arg;
  void *struct_value_ptr;

  argp = stack;

  if (ecif->cif->rtype->type == FFI_TYPE_STRUCT
      && ecif->cif->rtype->size > 8)
    struct_value_ptr = ecif->rvalue;
  else
    struct_value_ptr = NULL;

  p_argv = ecif->avalue;

  for (i = ecif->cif->nargs, p_arg = ecif->cif->arg_types;
       i != 0;
       i--, p_arg++)
    {
      size_t z;

      /* Align if necessary.  */
      if (((*p_arg)->alignment - 1) & (unsigned) argp)
	argp = (char *) ALIGN (argp, (*p_arg)->alignment);

	  z = (*p_arg)->size;
	  if (z < sizeof (int))
	    {
	      switch ((*p_arg)->type)
		{
		case FFI_TYPE_SINT8:
		  *(signed int *) argp = (signed int) *(SINT8 *) *p_argv;
		  break;

		case FFI_TYPE_UINT8:
		  *(unsigned int *) argp = (unsigned int) *(UINT8 *) *p_argv;
		  break;

		case FFI_TYPE_SINT16:
		  *(signed int *) argp = (signed int) *(SINT16 *) *p_argv;
		  break;

		case FFI_TYPE_UINT16:
		  *(unsigned int *) argp = (unsigned int) *(UINT16 *) *p_argv;
		  break;

		case FFI_TYPE_STRUCT:
		  memcpy (argp + sizeof (int) - z, *p_argv, z);
		  break;

		default:
		  FFI_ASSERT (0);
		}
	      z = sizeof (int);
	    }
	  else
	    memcpy (argp, *p_argv, z);
	  p_argv++;
	  argp += z;
    }

  return struct_value_ptr;
}

#define CIF_FLAGS_INT		1
#define CIF_FLAGS_DINT		2
#define CIF_FLAGS_FLOAT		4
#define CIF_FLAGS_DOUBLE	8
#define CIF_FLAGS_LDOUBLE	16
#define CIF_FLAGS_POINTER	32
#define CIF_FLAGS_STRUCT	64

/* Perform machine dependent cif processing */
ffi_status
ffi_prep_cif_machdep (ffi_cif *cif)
{
  /* Set the return type flag */
  switch (cif->rtype->type)
    {
    case FFI_TYPE_VOID:
      cif->flags = 0;
      break;

    case FFI_TYPE_STRUCT:
      if (cif->rtype->size > 4 && cif->rtype->size <= 8)
	cif->flags = CIF_FLAGS_DINT;
      else if (cif->rtype->size <= 4)
	cif->flags = CIF_FLAGS_STRUCT;
      else
	cif->flags = 0;
      break;

    case FFI_TYPE_FLOAT:
      cif->flags = CIF_FLAGS_FLOAT;
      break;

    case FFI_TYPE_DOUBLE:
      cif->flags = CIF_FLAGS_DOUBLE;
      break;

    case FFI_TYPE_LONGDOUBLE:
      cif->flags = CIF_FLAGS_LDOUBLE;
      break;

    case FFI_TYPE_POINTER:
      cif->flags = CIF_FLAGS_POINTER;
      break;

    case FFI_TYPE_SINT64:
    case FFI_TYPE_UINT64:
      cif->flags = CIF_FLAGS_DINT;
      break;

    default:
      cif->flags = CIF_FLAGS_INT;
      break;
    }

  return FFI_OK;
}

extern void ffi_call_SYSV (void *(*) (void *, extended_cif *), 
			   extended_cif *, 
			   unsigned, unsigned, unsigned,
			   void *, void (*fn) ());

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
      && cif->rtype->size > 8)
    ecif.rvalue = alloca (cif->rtype->size);
  else
    ecif.rvalue = rvalue;
    
  
  switch (cif->abi) 
    {
    case FFI_SYSV:
      ffi_call_SYSV (ffi_prep_args, &ecif, cif->bytes, 
		     cif->flags, cif->rtype->size * 8,
		     ecif.rvalue, fn);
      break;

    default:
      FFI_ASSERT (0);
      break;
    }
}