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/* -----------------------------------------------------------------------

   ffi.c - Copyright (c) 1998 Red Hat, Inc.

           Copyright (c) 2000 Hewlett Packard Company

   IA64 Foreign Function Interface

   Permission is hereby granted, free of charge, to any person obtaining

   a copy of this software and associated documentation files (the

   ``Software''), to deal in the Software without restriction, including

   without limitation the rights to use, copy, modify, merge, publish,

   distribute, sublicense, and/or sell copies of the Software, and to

   permit persons to whom the Software is furnished to do so, subject to

   the following conditions:

   The above copyright notice and this permission notice shall be included

   in all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS

   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

   IN NO EVENT SHALL CYGNUS SOLUTIONS BE LIABLE FOR ANY CLAIM, DAMAGES OR

   OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,

   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

   OTHER DEALINGS IN THE SOFTWARE.

   ----------------------------------------------------------------------- */

#include <ffi.h>

#include <ffi_common.h>

#include <stdlib.h>

#include <stdbool.h>

#include <float.h>

#include "ia64_flags.h"

/* A 64-bit pointer value.  In LP64 mode, this is effectively a plain

   pointer.  In ILP32 mode, it's a pointer that's been extended to

   64 bits by "addp4".  */

typedef void *PTR64 __attribute__((mode(DI)));

/* Memory image of fp register contents.  This is the implementation

   specific format used by ldf.fill/stf.spill.  All we care about is

   that it wants a 16 byte aligned slot.  */

typedef struct

{

  UINT64 x[2] __attribute__((aligned(16)));

} fpreg;

/* The stack layout given to ffi_call_unix and ffi_closure_unix_inner.  */

struct ia64_args

{

  fpreg fp_regs[8];     /* Contents of 8 fp arg registers.  */

  UINT64 gp_regs[8];    /* Contents of 8 gp arg registers.  */

  UINT64 other_args[];  /* Arguments passed on stack, variable size.  */

};

/* Adjust ADDR, a pointer to an 8 byte slot, to point to the low LEN bytes.  */

static inline void *

endian_adjust (void *addr, size_t len)

{

#ifdef __BIG_ENDIAN__

  return addr + (8 - len);

#else

  return addr;

#endif

}

/* Store VALUE to ADDR in the current cpu implementation's fp spill format.  */

static inline void

stf_spill(fpreg *addr, __float80 value)

{

  asm ("stf.spill %0 = %1%P0" : "=m" (*addr) : "f"(value));

}

/* Load a value from ADDR, which is in the current cpu implementation's

   fp spill format.  */

static inline __float80

ldf_fill(fpreg *addr)

{

  __float80 ret;

  asm ("ldf.fill %0 = %1%P1" : "=f"(ret) : "m"(*addr));

  return ret;

}

/* Return the size of the C type associated with with TYPE.  Which will

   be one of the FFI_IA64_TYPE_HFA_* values.  */

static size_t

hfa_type_size (int type)

{

  switch (type)

    {

    case FFI_IA64_TYPE_HFA_FLOAT:

      return sizeof(float);

    case FFI_IA64_TYPE_HFA_DOUBLE:

      return sizeof(double);

    case FFI_IA64_TYPE_HFA_LDOUBLE:

      return sizeof(__float80);

    default:

      abort ();

    }

}

/* Load from ADDR a value indicated by TYPE.  Which will be one of

   the FFI_IA64_TYPE_HFA_* values.  */

static __float80

hfa_type_load (int type, void *addr)

{

  switch (type)

    {

    case FFI_IA64_TYPE_HFA_FLOAT:

      return *(float *) addr;

    case FFI_IA64_TYPE_HFA_DOUBLE:

      return *(double *) addr;

    case FFI_IA64_TYPE_HFA_LDOUBLE:

      return *(__float80 *) addr;

    default:

      abort ();

    }

}

/* Load VALUE into ADDR as indicated by TYPE.  Which will be one of

   the FFI_IA64_TYPE_HFA_* values.  */

static void

hfa_type_store (int type, void *addr, __float80 value)

{

  switch (type)

    {

    case FFI_IA64_TYPE_HFA_FLOAT:

      *(float *) addr = value;

      break;

    case FFI_IA64_TYPE_HFA_DOUBLE:

      *(double *) addr = value;

      break;

    case FFI_IA64_TYPE_HFA_LDOUBLE:

      *(__float80 *) addr = value;

      break;

    default:

      abort ();

    }

}

/* Is TYPE a struct containing floats, doubles, or extended doubles,

   all of the same fp type?  If so, return the element type.  Return

   FFI_TYPE_VOID if not.  */

static int

hfa_element_type (ffi_type *type, int nested)

{

  int element = FFI_TYPE_VOID;

  switch (type->type)

    {

    case FFI_TYPE_FLOAT:

      /* We want to return VOID for raw floating-point types, but the

         synthetic HFA type if we're nested within an aggregate.  */

      if (nested)

        element = FFI_IA64_TYPE_HFA_FLOAT;

      break;

    case FFI_TYPE_DOUBLE:

      /* Similarly.  */

      if (nested)

        element = FFI_IA64_TYPE_HFA_DOUBLE;

      break;

    case FFI_TYPE_LONGDOUBLE:

      /* Similarly, except that that HFA is true for double extended,

         but not quad precision.  Both have sizeof == 16, so tell the

         difference based on the precision.  */

      if (LDBL_MANT_DIG == 64 && nested)

        element = FFI_IA64_TYPE_HFA_LDOUBLE;

      break;

    case FFI_TYPE_STRUCT:

      {

        ffi_type **ptr = &type->elements[0];

        for (ptr = &type->elements[0]; *ptr ; ptr++)

          {

            int sub_element = hfa_element_type (*ptr, 1);

            if (sub_element == FFI_TYPE_VOID)

              return FFI_TYPE_VOID;

            if (element == FFI_TYPE_VOID)

              element = sub_element;

            else if (element != sub_element)

              return FFI_TYPE_VOID;

          }

      }

      break;

    default:

      return FFI_TYPE_VOID;

    }

  return element;

}

/* Perform machine dependent cif processing. */

ffi_status

ffi_prep_cif_machdep(ffi_cif *cif)

{

  int flags;

  /* Adjust cif->bytes to include space for the bits of the ia64_args frame

     that preceeds the integer register portion.  The estimate that the

     generic bits did for the argument space required is good enough for the

     integer component.  */

  cif->bytes += offsetof(struct ia64_args, gp_regs[0]);

  if (cif->bytes < sizeof(struct ia64_args))

    cif->bytes = sizeof(struct ia64_args);

  /* Set the return type flag. */

  flags = cif->rtype->type;

  switch (cif->rtype->type)

    {

    case FFI_TYPE_LONGDOUBLE:

      /* Leave FFI_TYPE_LONGDOUBLE as meaning double extended precision,

         and encode quad precision as a two-word integer structure.  */

      if (LDBL_MANT_DIG != 64)

        flags = FFI_IA64_TYPE_SMALL_STRUCT | (16 << 8);

      break;

    case FFI_TYPE_STRUCT:

      {

        size_t size = cif->rtype->size;

        int hfa_type = hfa_element_type (cif->rtype, 0);

        if (hfa_type != FFI_TYPE_VOID)

          {

            size_t nelts = size / hfa_type_size (hfa_type);

            if (nelts <= 8)

              flags = hfa_type | (size << 8);

          }

        else

          {

            if (size <= 32)

              flags = FFI_IA64_TYPE_SMALL_STRUCT | (size << 8);

          }

      }

      break;

    default:

      break;

    }

  cif->flags = flags;

  return FFI_OK;

}

extern int ffi_call_unix (struct ia64_args *, PTR64, void (*)(), UINT64);

void

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

{

  struct ia64_args *stack;

  long i, avn, gpcount, fpcount;

  ffi_type **p_arg;

  FFI_ASSERT (cif->abi == FFI_UNIX);

  /* If we have no spot for a return value, make one.  */

  if (rvalue == NULL && cif->rtype->type != FFI_TYPE_VOID)

    rvalue = alloca (cif->rtype->size);

  /* Allocate the stack frame.  */

  stack = alloca (cif->bytes);

  gpcount = fpcount = 0;

  avn = cif->nargs;

  for (i = 0, p_arg = cif->arg_types; i < avn; i++, p_arg++)

    {

      switch ((*p_arg)->type)

        {

        case FFI_TYPE_SINT8:

          stack->gp_regs[gpcount++] = *(SINT8 *)avalue[i];

          break;

        case FFI_TYPE_UINT8:

          stack->gp_regs[gpcount++] = *(UINT8 *)avalue[i];

          break;

        case FFI_TYPE_SINT16:

          stack->gp_regs[gpcount++] = *(SINT16 *)avalue[i];

          break;

        case FFI_TYPE_UINT16:

          stack->gp_regs[gpcount++] = *(UINT16 *)avalue[i];

          break;

        case FFI_TYPE_SINT32:

          stack->gp_regs[gpcount++] = *(SINT32 *)avalue[i];

          break;

        case FFI_TYPE_UINT32:

          stack->gp_regs[gpcount++] = *(UINT32 *)avalue[i];

          break;

        case FFI_TYPE_SINT64:

        case FFI_TYPE_UINT64:

          stack->gp_regs[gpcount++] = *(UINT64 *)avalue[i];

          break;

        case FFI_TYPE_POINTER:

          stack->gp_regs[gpcount++] = (UINT64)(PTR64) *(void **)avalue[i];

          break;

        case FFI_TYPE_FLOAT:

          if (gpcount < 8 && fpcount < 8)

            stf_spill (&stack->fp_regs[fpcount++], *(float *)avalue[i]);

          stack->gp_regs[gpcount++] = *(UINT32 *)avalue[i];

          break;

        case FFI_TYPE_DOUBLE:

          if (gpcount < 8 && fpcount < 8)

            stf_spill (&stack->fp_regs[fpcount++], *(double *)avalue[i]);

          stack->gp_regs[gpcount++] = *(UINT64 *)avalue[i];

          break;

        case FFI_TYPE_LONGDOUBLE:

          if (gpcount & 1)

            gpcount++;

          if (LDBL_MANT_DIG == 64 && gpcount < 8 && fpcount < 8)

            stf_spill (&stack->fp_regs[fpcount++], *(__float80 *)avalue[i]);

          memcpy (&stack->gp_regs[gpcount], avalue[i], 16);

          gpcount += 2;

          break;

        case FFI_TYPE_STRUCT:

          {

            size_t size = (*p_arg)->size;

            size_t align = (*p_arg)->alignment;

            int hfa_type = hfa_element_type (*p_arg, 0);

            FFI_ASSERT (align <= 16);

            if (align == 16 && (gpcount & 1))

              gpcount++;

            if (hfa_type != FFI_TYPE_VOID)

              {

                size_t hfa_size = hfa_type_size (hfa_type);

                size_t offset = 0;

                size_t gp_offset = gpcount * 8;

                while (fpcount < 8

                       && offset < size

                       && gp_offset < 8 * 8)

                  {

                    stf_spill (&stack->fp_regs[fpcount],

                               hfa_type_load (hfa_type, avalue[i] + offset));

                    offset += hfa_size;

                    gp_offset += hfa_size;

                    fpcount += 1;

                  }

              }

            memcpy (&stack->gp_regs[gpcount], avalue[i], size);

            gpcount += (size + 7) / 8;

          }

          break;

        default:

          abort ();

        }

    }

  ffi_call_unix (stack, rvalue, fn, cif->flags);

}

/* Closures represent a pair consisting of a function pointer, and

   some user data.  A closure is invoked by reinterpreting the closure

   as a function pointer, and branching to it.  Thus we can make an

   interpreted function callable as a C function: We turn the

   interpreter itself, together with a pointer specifying the

   interpreted procedure, into a closure.

   For IA64, function pointer are already pairs consisting of a code

   pointer, and a gp pointer.  The latter is needed to access global

   variables.  Here we set up such a pair as the first two words of

   the closure (in the "trampoline" area), but we replace the gp

   pointer with a pointer to the closure itself.  We also add the real

   gp pointer to the closure.  This allows the function entry code to

   both retrieve the user data, and to restire the correct gp pointer.  */

extern void ffi_closure_unix ();

ffi_status

ffi_prep_closure (ffi_closure* closure,

                  ffi_cif* cif,

                  void (*fun)(ffi_cif*,void*,void**,void*),

                  void *user_data)

{

  /* The layout of a function descriptor.  A C function pointer really

     points to one of these.  */

  struct ia64_fd

  {

    UINT64 code_pointer;

    UINT64 gp;

  };

  struct ffi_ia64_trampoline_struct

  {

    UINT64 code_pointer;        /* Pointer to ffi_closure_unix.  */

    UINT64 fake_gp;             /* Pointer to closure, installed as gp.  */

    UINT64 real_gp;             /* Real gp value.  */

  };

  struct ffi_ia64_trampoline_struct *tramp;

  struct ia64_fd *fd;

  FFI_ASSERT (cif->abi == FFI_UNIX);

  tramp = (struct ffi_ia64_trampoline_struct *)closure->tramp;

  fd = (struct ia64_fd *)(void *)ffi_closure_unix;

  tramp->code_pointer = fd->code_pointer;

  tramp->real_gp = fd->gp;

  tramp->fake_gp = (UINT64)(PTR64)closure;

  closure->cif = cif;

  closure->user_data = user_data;

  closure->fun = fun;

  return FFI_OK;

}

UINT64

ffi_closure_unix_inner (ffi_closure *closure, struct ia64_args *stack,

                        void *rvalue, void *r8)

{

  ffi_cif *cif;

  void **avalue;

  ffi_type **p_arg;

  long i, avn, gpcount, fpcount;

  cif = closure->cif;

  avn = cif->nargs;

  avalue = alloca (avn * sizeof (void *));

  /* If the structure return value is passed in memory get that location

     from r8 so as to pass the value directly back to the caller.  */

  if (cif->flags == FFI_TYPE_STRUCT)

    rvalue = r8;

  gpcount = fpcount = 0;

  for (i = 0, p_arg = cif->arg_types; i < avn; i++, p_arg++)

    {

      switch ((*p_arg)->type)

        {

        case FFI_TYPE_SINT8:

        case FFI_TYPE_UINT8:

          avalue[i] = endian_adjust(&stack->gp_regs[gpcount++], 1);

          break;

        case FFI_TYPE_SINT16:

        case FFI_TYPE_UINT16:

          avalue[i] = endian_adjust(&stack->gp_regs[gpcount++], 2);

          break;

        case FFI_TYPE_SINT32:

        case FFI_TYPE_UINT32:

          avalue[i] = endian_adjust(&stack->gp_regs[gpcount++], 4);

          break;

        case FFI_TYPE_SINT64:

        case FFI_TYPE_UINT64:

          avalue[i] = &stack->gp_regs[gpcount++];

          break;

        case FFI_TYPE_POINTER:

          avalue[i] = endian_adjust(&stack->gp_regs[gpcount++], sizeof(void*));

          break;

        case FFI_TYPE_FLOAT:

          if (gpcount < 8 && fpcount < 8)

            {

              void *addr = &stack->fp_regs[fpcount++];

              avalue[i] = addr;

              *(float *)addr = ldf_fill (addr);

            }

          else

            avalue[i] = endian_adjust(&stack->gp_regs[gpcount], 4);

          gpcount++;

          break;

        case FFI_TYPE_DOUBLE:

          if (gpcount < 8 && fpcount < 8)

            {

              void *addr = &stack->fp_regs[fpcount++];

              avalue[i] = addr;

              *(double *)addr = ldf_fill (addr);

            }

          else

            avalue[i] = &stack->gp_regs[gpcount];

          gpcount++;

          break;

        case FFI_TYPE_LONGDOUBLE:

          if (gpcount & 1)

            gpcount++;

          if (LDBL_MANT_DIG == 64 && gpcount < 8 && fpcount < 8)

            {

              void *addr = &stack->fp_regs[fpcount++];

              avalue[i] = addr;

              *(__float80 *)addr = ldf_fill (addr);

            }

          else

            avalue[i] = &stack->gp_regs[gpcount];

          gpcount += 2;

          break;

        case FFI_TYPE_STRUCT:

          {

            size_t size = (*p_arg)->size;

            size_t align = (*p_arg)->alignment;

            int hfa_type = hfa_element_type (*p_arg, 0);

            FFI_ASSERT (align <= 16);

            if (align == 16 && (gpcount & 1))

              gpcount++;

            if (hfa_type != FFI_TYPE_VOID)

              {

                size_t hfa_size = hfa_type_size (hfa_type);

                size_t offset = 0;

                size_t gp_offset = gpcount * 8;

                void *addr = alloca (size);

                avalue[i] = addr;

                while (fpcount < 8

                       && offset < size

                       && gp_offset < 8 * 8)

                  {

                    hfa_type_store (hfa_type, addr + offset,

                                    ldf_fill (&stack->fp_regs[fpcount]));

                    offset += hfa_size;

                    gp_offset += hfa_size;

                    fpcount += 1;

                  }

                if (offset < size)

                  memcpy (addr + offset, (char *)stack->gp_regs + gp_offset,

                          size - offset);

              }

            else

              avalue[i] = &stack->gp_regs[gpcount];

            gpcount += (size + 7) / 8;

          }

          break;

        default:

          abort ();

        }

    }

  closure->fun (cif, rvalue, avalue, closure->user_data);

  return cif->flags;

}