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plt-scheme  4.2.1
Defines | Functions
ffi.c File Reference
#include <ffi.h>
#include <ffi_common.h>
#include <stdlib.h>
#include <stdio.h>

Go to the source code of this file.

Defines

#define MAX_GPRARGS   5
#define MAX_FPRARGS   2
#define ROUND_SIZE(size)   (((size) + 15) & ~15)
#define FFI390_RET_VOID   0
#define FFI390_RET_STRUCT   1
#define FFI390_RET_FLOAT   2
#define FFI390_RET_DOUBLE   3
#define FFI390_RET_INT32   4
#define FFI390_RET_INT64   5

Functions

static void ffi_prep_args (unsigned char *, extended_cif *)
void ffi_closure_helper_SYSV (ffi_closure *, unsigned long *, unsigned long long *, unsigned long *)
void ffi_call_SYSV (unsigned, extended_cif *, void(*)(unsigned char *, extended_cif *), unsigned, void *, void(*fn)())
void ffi_closure_SYSV (void)
static int ffi_check_struct_type (ffi_type *arg)
ffi_status ffi_prep_cif_machdep (ffi_cif *cif)
void ffi_call (ffi_cif *cif, void(*fn)(), void *rvalue, void **avalue)
ffi_status ffi_prep_closure_loc (ffi_closure *closure, ffi_cif *cif, void(*fun)(ffi_cif *, void *, void **, void *), void *user_data, void *codeloc)

Define Documentation

#define FFI390_RET_DOUBLE   3

Definition at line 60 of file ffi.c.

#define FFI390_RET_FLOAT   2

Definition at line 59 of file ffi.c.

#define FFI390_RET_INT32   4

Definition at line 61 of file ffi.c.

#define FFI390_RET_INT64   5

Definition at line 62 of file ffi.c.

#define FFI390_RET_STRUCT   1

Definition at line 58 of file ffi.c.

#define FFI390_RET_VOID   0

Definition at line 57 of file ffi.c.

#define MAX_FPRARGS   2

Definition at line 50 of file ffi.c.

#define MAX_GPRARGS   5

Definition at line 44 of file ffi.c.

#define ROUND_SIZE (   size)    (((size) + 15) & ~15)

Definition at line 54 of file ffi.c.


Function Documentation

void ffi_call ( ffi_cif *  cif,
void(*)()  fn,
void rvalue,
void **  avalue 
)

Definition at line 500 of file ffi.c.

{
  int ret_type = cif->flags;
  extended_cif ecif;
 
  ecif.cif    = cif;
  ecif.avalue = avalue;
  ecif.rvalue = rvalue;

  /* If we don't have a return value, we need to fake one.  */
  if (rvalue == NULL)
    {
      if (ret_type == FFI390_RET_STRUCT)
       ecif.rvalue = alloca (cif->rtype->size);
      else
       ret_type = FFI390_RET_VOID;
    } 

  switch (cif->abi)
    {
      case FFI_SYSV:
        ffi_call_SYSV (cif->bytes, &ecif, ffi_prep_args,
                     ret_type, ecif.rvalue, fn);
        break;
 
      default:
        FFI_ASSERT (0);
        break;
    }
}

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void ffi_call_SYSV ( unsigned  ,
extended_cif ,
void(*)(unsigned char *, extended_cif *)  ,
unsigned  ,
void ,
void(*)()  fn 
)
static int ffi_check_struct_type ( ffi_type *  arg) [static]

Definition at line 107 of file ffi.c.

{
  size_t size = arg->size;

  /* If the struct has just one element, look at that element
     to find out whether to consider the struct as floating point.  */
  while (arg->type == FFI_TYPE_STRUCT 
         && arg->elements[0] && !arg->elements[1])
    arg = arg->elements[0];

  /* Structs of size 1, 2, 4, and 8 are passed in registers,
     just like the corresponding int/float types.  */
  switch (size)
    {
      case 1:
        return FFI_TYPE_UINT8;

      case 2:
        return FFI_TYPE_UINT16;

      case 4:
       if (arg->type == FFI_TYPE_FLOAT)
          return FFI_TYPE_FLOAT;
       else
         return FFI_TYPE_UINT32;

      case 8:
       if (arg->type == FFI_TYPE_DOUBLE)
          return FFI_TYPE_DOUBLE;
       else
         return FFI_TYPE_UINT64;

      default:
       break;
    }

  /* Other structs are passed via a pointer to the data.  */
  return FFI_TYPE_POINTER;
}

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void ffi_closure_helper_SYSV ( ffi_closure *  closure,
unsigned long *  p_gpr,
unsigned long long *  p_fpr,
unsigned long *  p_ov 
)

Definition at line 545 of file ffi.c.

{
  unsigned long long ret_buffer;

  void *rvalue = &ret_buffer;
  void **avalue;
  void **p_arg;

  int n_gpr = 0;
  int n_fpr = 0;
  int n_ov = 0;

  ffi_type **ptr;
  int i;

  /* Allocate buffer for argument list pointers.  */

  p_arg = avalue = alloca (closure->cif->nargs * sizeof (void *));

  /* If we returning a structure, pass the structure address 
     directly to the target function.  Otherwise, have the target 
     function store the return value to the GPR save area.  */

  if (closure->cif->flags == FFI390_RET_STRUCT)
    rvalue = (void *) p_gpr[n_gpr++];

  /* Now for the arguments.  */

  for (ptr = closure->cif->arg_types, i = closure->cif->nargs;
       i > 0;
       i--, p_arg++, ptr++)
    {
      int deref_struct_pointer = 0;
      int type = (*ptr)->type;

#if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
      /* 16-byte long double is passed like a struct.  */
      if (type == FFI_TYPE_LONGDOUBLE)
       type = FFI_TYPE_STRUCT;
#endif

      /* Check how a structure type is passed.  */
      if (type == FFI_TYPE_STRUCT)
       {
         type = ffi_check_struct_type (*ptr);

         /* If we pass the struct via pointer, remember to 
            retrieve the pointer later.  */
         if (type == FFI_TYPE_POINTER)
           deref_struct_pointer = 1;
       }

      /* Pointers are passed like UINTs of the same size.  */
      if (type == FFI_TYPE_POINTER)
#ifdef __s390x__
       type = FFI_TYPE_UINT64;
#else
       type = FFI_TYPE_UINT32;
#endif

      /* Now handle all primitive int/float data types.  */
      switch (type) 
       {
         case FFI_TYPE_DOUBLE:
           if (n_fpr < MAX_FPRARGS)
             *p_arg = &p_fpr[n_fpr++];
           else
             *p_arg = &p_ov[n_ov], 
             n_ov += sizeof (double) / sizeof (long);
           break;
       
         case FFI_TYPE_FLOAT:
           if (n_fpr < MAX_FPRARGS)
             *p_arg = &p_fpr[n_fpr++];
           else
             *p_arg = (char *)&p_ov[n_ov++] + sizeof (long) - 4;
           break;
 
         case FFI_TYPE_UINT64:
         case FFI_TYPE_SINT64:
#ifdef __s390x__
           if (n_gpr < MAX_GPRARGS)
             *p_arg = &p_gpr[n_gpr++];
           else
             *p_arg = &p_ov[n_ov++];
#else
           if (n_gpr == MAX_GPRARGS-1)
             n_gpr = MAX_GPRARGS;
           if (n_gpr < MAX_GPRARGS)
             *p_arg = &p_gpr[n_gpr], n_gpr += 2;
           else
             *p_arg = &p_ov[n_ov], n_ov += 2;
#endif
           break;
 
         case FFI_TYPE_INT:
         case FFI_TYPE_UINT32:
         case FFI_TYPE_SINT32:
           if (n_gpr < MAX_GPRARGS)
             *p_arg = (char *)&p_gpr[n_gpr++] + sizeof (long) - 4;
           else
             *p_arg = (char *)&p_ov[n_ov++] + sizeof (long) - 4;
           break;
 
         case FFI_TYPE_UINT16:
         case FFI_TYPE_SINT16:
           if (n_gpr < MAX_GPRARGS)
             *p_arg = (char *)&p_gpr[n_gpr++] + sizeof (long) - 2;
           else
             *p_arg = (char *)&p_ov[n_ov++] + sizeof (long) - 2;
           break;

         case FFI_TYPE_UINT8:
         case FFI_TYPE_SINT8:
           if (n_gpr < MAX_GPRARGS)
             *p_arg = (char *)&p_gpr[n_gpr++] + sizeof (long) - 1;
           else
             *p_arg = (char *)&p_ov[n_ov++] + sizeof (long) - 1;
           break;
 
         default:
           FFI_ASSERT (0);
           break;
        }

      /* If this is a struct passed via pointer, we need to
        actually retrieve that pointer.  */
      if (deref_struct_pointer)
       *p_arg = *(void **)*p_arg;
    }


  /* Call the target function.  */
  (closure->fun) (closure->cif, rvalue, avalue, closure->user_data);

  /* Convert the return value.  */
  switch (closure->cif->rtype->type)
    {
      /* Void is easy, and so is struct.  */
      case FFI_TYPE_VOID:
      case FFI_TYPE_STRUCT:
#if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
      case FFI_TYPE_LONGDOUBLE:
#endif
       break;

      /* Floating point values are returned in fpr 0.  */
      case FFI_TYPE_FLOAT:
       p_fpr[0] = (long long) *(unsigned int *) rvalue << 32;
       break;

      case FFI_TYPE_DOUBLE:
       p_fpr[0] = *(unsigned long long *) rvalue;
       break;

      /* Integer values are returned in gpr 2 (and gpr 3
        for 64-bit values on 31-bit machines).  */
      case FFI_TYPE_UINT64:
      case FFI_TYPE_SINT64:
#ifdef __s390x__
       p_gpr[0] = *(unsigned long *) rvalue;
#else
       p_gpr[0] = ((unsigned long *) rvalue)[0],
       p_gpr[1] = ((unsigned long *) rvalue)[1];
#endif
       break;

      case FFI_TYPE_POINTER:
      case FFI_TYPE_UINT32:
      case FFI_TYPE_UINT16:
      case FFI_TYPE_UINT8:
       p_gpr[0] = *(unsigned long *) rvalue;
       break;

      case FFI_TYPE_INT:
      case FFI_TYPE_SINT32:
      case FFI_TYPE_SINT16:
      case FFI_TYPE_SINT8:
       p_gpr[0] = *(signed long *) rvalue;
       break;

      default:
        FFI_ASSERT (0);
        break;
    }
}

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static void ffi_prep_args ( unsigned char *  stack,
extended_cif ecif 
) [static]

Definition at line 161 of file ffi.c.

{
  /* The stack space will be filled with those areas:

       FPR argument register save area     (highest addresses)
       GPR argument register save area
       temporary struct copies
       overflow argument area              (lowest addresses)

     We set up the following pointers:

        p_fpr: bottom of the FPR area (growing upwards)
       p_gpr: bottom of the GPR area (growing upwards)
       p_ov: bottom of the overflow area (growing upwards)
       p_struct: top of the struct copy area (growing downwards)

     All areas are kept aligned to twice the word size.  */

  int gpr_off = ecif->cif->bytes;
  int fpr_off = gpr_off + ROUND_SIZE (MAX_GPRARGS * sizeof (long));

  unsigned long long *p_fpr = (unsigned long long *)(stack + fpr_off);
  unsigned long *p_gpr = (unsigned long *)(stack + gpr_off);
  unsigned char *p_struct = (unsigned char *)p_gpr;
  unsigned long *p_ov = (unsigned long *)stack;

  int n_fpr = 0;
  int n_gpr = 0;
  int n_ov = 0;

  ffi_type **ptr;
  void **p_argv = ecif->avalue;
  int i;
 
  /* If we returning a structure then we set the first parameter register
     to the address of where we are returning this structure.  */

  if (ecif->cif->flags == FFI390_RET_STRUCT)
    p_gpr[n_gpr++] = (unsigned long) ecif->rvalue;

  /* Now for the arguments.  */
 
  for (ptr = ecif->cif->arg_types, i = ecif->cif->nargs;
       i > 0;
       i--, ptr++, p_argv++)
    {
      void *arg = *p_argv;
      int type = (*ptr)->type;

#if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
      /* 16-byte long double is passed like a struct.  */
      if (type == FFI_TYPE_LONGDOUBLE)
       type = FFI_TYPE_STRUCT;
#endif

      /* Check how a structure type is passed.  */
      if (type == FFI_TYPE_STRUCT)
       {
         type = ffi_check_struct_type (*ptr);

         /* If we pass the struct via pointer, copy the data.  */
         if (type == FFI_TYPE_POINTER)
           {
             p_struct -= ROUND_SIZE ((*ptr)->size);
             memcpy (p_struct, (char *)arg, (*ptr)->size);
             arg = &p_struct;
           }
       }

      /* Now handle all primitive int/pointer/float data types.  */
      switch (type) 
       {
         case FFI_TYPE_DOUBLE:
           if (n_fpr < MAX_FPRARGS)
             p_fpr[n_fpr++] = *(unsigned long long *) arg;
           else
#ifdef __s390x__
             p_ov[n_ov++] = *(unsigned long *) arg;
#else
             p_ov[n_ov++] = ((unsigned long *) arg)[0],
             p_ov[n_ov++] = ((unsigned long *) arg)[1];
#endif
           break;
       
         case FFI_TYPE_FLOAT:
           if (n_fpr < MAX_FPRARGS)
             p_fpr[n_fpr++] = (long long) *(unsigned int *) arg << 32;
           else
             p_ov[n_ov++] = *(unsigned int *) arg;
           break;

         case FFI_TYPE_POINTER:
           if (n_gpr < MAX_GPRARGS)
             p_gpr[n_gpr++] = (unsigned long)*(unsigned char **) arg;
           else
             p_ov[n_ov++] = (unsigned long)*(unsigned char **) arg;
           break;
 
         case FFI_TYPE_UINT64:
         case FFI_TYPE_SINT64:
#ifdef __s390x__
           if (n_gpr < MAX_GPRARGS)
             p_gpr[n_gpr++] = *(unsigned long *) arg;
           else
             p_ov[n_ov++] = *(unsigned long *) arg;
#else
           if (n_gpr == MAX_GPRARGS-1)
             n_gpr = MAX_GPRARGS;
           if (n_gpr < MAX_GPRARGS)
             p_gpr[n_gpr++] = ((unsigned long *) arg)[0],
             p_gpr[n_gpr++] = ((unsigned long *) arg)[1];
           else
             p_ov[n_ov++] = ((unsigned long *) arg)[0],
             p_ov[n_ov++] = ((unsigned long *) arg)[1];
#endif
           break;
 
         case FFI_TYPE_UINT32:
           if (n_gpr < MAX_GPRARGS)
             p_gpr[n_gpr++] = *(unsigned int *) arg;
           else
             p_ov[n_ov++] = *(unsigned int *) arg;
           break;
 
         case FFI_TYPE_INT:
         case FFI_TYPE_SINT32:
           if (n_gpr < MAX_GPRARGS)
             p_gpr[n_gpr++] = *(signed int *) arg;
           else
             p_ov[n_ov++] = *(signed int *) arg;
           break;
 
         case FFI_TYPE_UINT16:
           if (n_gpr < MAX_GPRARGS)
             p_gpr[n_gpr++] = *(unsigned short *) arg;
           else
             p_ov[n_ov++] = *(unsigned short *) arg;
           break;
 
         case FFI_TYPE_SINT16:
           if (n_gpr < MAX_GPRARGS)
             p_gpr[n_gpr++] = *(signed short *) arg;
           else
             p_ov[n_ov++] = *(signed short *) arg;
           break;

         case FFI_TYPE_UINT8:
           if (n_gpr < MAX_GPRARGS)
             p_gpr[n_gpr++] = *(unsigned char *) arg;
           else
             p_ov[n_ov++] = *(unsigned char *) arg;
           break;
 
         case FFI_TYPE_SINT8:
           if (n_gpr < MAX_GPRARGS)
             p_gpr[n_gpr++] = *(signed char *) arg;
           else
             p_ov[n_ov++] = *(signed char *) arg;
           break;
 
         default:
           FFI_ASSERT (0);
           break;
        }
    }
}

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ffi_status ffi_prep_cif_machdep ( ffi_cif *  cif)

Definition at line 339 of file ffi.c.

{
  size_t struct_size = 0;
  int n_gpr = 0;
  int n_fpr = 0;
  int n_ov = 0;

  ffi_type **ptr;
  int i;

  /* Determine return value handling.  */ 

  switch (cif->rtype->type)
    {
      /* Void is easy.  */
      case FFI_TYPE_VOID:
       cif->flags = FFI390_RET_VOID;
       break;

      /* Structures are returned via a hidden pointer.  */
      case FFI_TYPE_STRUCT:
       cif->flags = FFI390_RET_STRUCT;
       n_gpr++;  /* We need one GPR to pass the pointer.  */
       break; 

      /* Floating point values are returned in fpr 0.  */
      case FFI_TYPE_FLOAT:
       cif->flags = FFI390_RET_FLOAT;
       break;

      case FFI_TYPE_DOUBLE:
       cif->flags = FFI390_RET_DOUBLE;
       break;

#if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
      case FFI_TYPE_LONGDOUBLE:
       cif->flags = FFI390_RET_STRUCT;
       n_gpr++;
       break;
#endif
      /* Integer values are returned in gpr 2 (and gpr 3
        for 64-bit values on 31-bit machines).  */
      case FFI_TYPE_UINT64:
      case FFI_TYPE_SINT64:
       cif->flags = FFI390_RET_INT64;
       break;

      case FFI_TYPE_POINTER:
      case FFI_TYPE_INT:
      case FFI_TYPE_UINT32:
      case FFI_TYPE_SINT32:
      case FFI_TYPE_UINT16:
      case FFI_TYPE_SINT16:
      case FFI_TYPE_UINT8:
      case FFI_TYPE_SINT8:
       /* These are to be extended to word size.  */
#ifdef __s390x__
       cif->flags = FFI390_RET_INT64;
#else
       cif->flags = FFI390_RET_INT32;
#endif
       break;
 
      default:
        FFI_ASSERT (0);
        break;
    }

  /* Now for the arguments.  */
 
  for (ptr = cif->arg_types, i = cif->nargs;
       i > 0;
       i--, ptr++)
    {
      int type = (*ptr)->type;

#if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
      /* 16-byte long double is passed like a struct.  */
      if (type == FFI_TYPE_LONGDOUBLE)
       type = FFI_TYPE_STRUCT;
#endif

      /* Check how a structure type is passed.  */
      if (type == FFI_TYPE_STRUCT)
       {
         type = ffi_check_struct_type (*ptr);

         /* If we pass the struct via pointer, we must reserve space
            to copy its data for proper call-by-value semantics.  */
         if (type == FFI_TYPE_POINTER)
           struct_size += ROUND_SIZE ((*ptr)->size);
       }

      /* Now handle all primitive int/float data types.  */
      switch (type) 
       {
         /* The first MAX_FPRARGS floating point arguments
            go in FPRs, the rest overflow to the stack.  */

         case FFI_TYPE_DOUBLE:
           if (n_fpr < MAX_FPRARGS)
             n_fpr++;
           else
             n_ov += sizeof (double) / sizeof (long);
           break;
       
         case FFI_TYPE_FLOAT:
           if (n_fpr < MAX_FPRARGS)
             n_fpr++;
           else
             n_ov++;
           break;

         /* On 31-bit machines, 64-bit integers are passed in GPR pairs,
            if one is still available, or else on the stack.  If only one
            register is free, skip the register (it won't be used for any 
            subsequent argument either).  */
             
#ifndef __s390x__
         case FFI_TYPE_UINT64:
         case FFI_TYPE_SINT64:
           if (n_gpr == MAX_GPRARGS-1)
             n_gpr = MAX_GPRARGS;
           if (n_gpr < MAX_GPRARGS)
             n_gpr += 2;
           else
             n_ov += 2;
           break;
#endif

         /* Everything else is passed in GPRs (until MAX_GPRARGS
            have been used) or overflows to the stack.  */

         default: 
           if (n_gpr < MAX_GPRARGS)
             n_gpr++;
           else
             n_ov++;
           break;
        }
    }

  /* Total stack space as required for overflow arguments
     and temporary structure copies.  */

  cif->bytes = ROUND_SIZE (n_ov * sizeof (long)) + struct_size;
 
  return FFI_OK;
}

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ffi_status ffi_prep_closure_loc ( ffi_closure *  closure,
ffi_cif *  cif,
void(*)(ffi_cif *, void *, void **, void *)  fun,
void user_data,
void codeloc 
)

Definition at line 746 of file ffi.c.

{
  FFI_ASSERT (cif->abi == FFI_SYSV);

#ifndef __s390x__
  *(short *)&closure->tramp [0] = 0x0d10;   /* basr %r1,0 */
  *(short *)&closure->tramp [2] = 0x9801;   /* lm %r0,%r1,6(%r1) */
  *(short *)&closure->tramp [4] = 0x1006;
  *(short *)&closure->tramp [6] = 0x07f1;   /* br %r1 */
  *(long  *)&closure->tramp [8] = (long)codeloc;
  *(long  *)&closure->tramp[12] = (long)&ffi_closure_SYSV;
#else
  *(short *)&closure->tramp [0] = 0x0d10;   /* basr %r1,0 */
  *(short *)&closure->tramp [2] = 0xeb01;   /* lmg %r0,%r1,14(%r1) */
  *(short *)&closure->tramp [4] = 0x100e;
  *(short *)&closure->tramp [6] = 0x0004;
  *(short *)&closure->tramp [8] = 0x07f1;   /* br %r1 */
  *(long  *)&closure->tramp[16] = (long)codeloc;
  *(long  *)&closure->tramp[24] = (long)&ffi_closure_SYSV;
#endif 
 
  closure->cif = cif;
  closure->user_data = user_data;
  closure->fun = fun;
 
  return FFI_OK;
}

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