/* Copyright 2001,2009-2015,2018,2025
     Free Software Foundation, Inc.

   This file is part of Guile.

   Guile is free software: you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published
   by the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Guile is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
   License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with Guile.  If not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef _SCM_FRAMES_INTERNAL_H_
#define _SCM_FRAMES_INTERNAL_H_

#include <libguile/frames.h>


struct scm_frame 
{
  void *stack_holder;
  ptrdiff_t fp_offset;
  ptrdiff_t sp_offset;
  uint32_t *ip;
};

struct scm_vm_frame
{
  scm_t_bits tag_and_flags;
  struct scm_frame frame;
};

enum scm_vm_frame_kind
{
  SCM_VM_FRAME_KIND_VM,
  SCM_VM_FRAME_KIND_CONT
};

static inline int
scm_is_vm_frame (SCM x)
{
  return SCM_HAS_TYP7 (x, scm_tc7_frame);
}

#define SCM_VM_FRAME_P(x)		(scm_is_vm_frame (x))
#define SCM_VALIDATE_VM_FRAME(p,x)	SCM_MAKE_VALIDATE (p, x, VM_FRAME_P)

static inline struct scm_vm_frame*
scm_vm_frame (SCM x)
{
  if (!scm_is_vm_frame (x))
    abort ();
  return (struct scm_vm_frame *) SCM_UNPACK_POINTER (x);
}

static inline enum scm_vm_frame_kind
scm_vm_frame_kind (struct scm_vm_frame *frame)
{
  return (enum scm_vm_frame_kind) (frame->tag_and_flags >> 8);
}

SCM_INTERNAL union scm_vm_stack_element*
scm_vm_frame_stack_top (struct scm_vm_frame *frame);

static inline union scm_vm_stack_element*
scm_vm_frame_fp (struct scm_vm_frame *frame)
{
  return scm_vm_frame_stack_top (frame) - frame->frame.fp_offset;
}

static inline union scm_vm_stack_element*
scm_vm_frame_sp (struct scm_vm_frame *frame)
{
  return scm_vm_frame_stack_top (frame) - frame->frame.sp_offset;
}

static inline uint32_t*
scm_vm_frame_ip (struct scm_vm_frame *frame)
{
  return frame->frame.ip;
}

/* See notes in frames.c before using this.  */
SCM_INTERNAL SCM scm_c_frame_closure (enum scm_vm_frame_kind kind,
                                      const struct scm_frame *frame);

SCM_INTERNAL SCM scm_c_make_frame (enum scm_vm_frame_kind kind,
                                   const struct scm_frame *frame);

SCM_INTERNAL int scm_c_frame_previous (enum scm_vm_frame_kind kind,
                                       struct scm_frame *frame);

static inline void
scm_frame_init_from_vm_frame (struct scm_frame *frame,
                              const struct scm_vm_frame *vm_frame)
{
  memcpy (frame, &vm_frame->frame, sizeof (*frame));
}

SCM_INTERNAL void scm_i_frame_print (SCM frame, SCM port,
                                     scm_print_state *pstate);
SCM_INTERNAL void scm_init_frames (void);

#endif /* _SCM_FRAMES_INTERNAL_H_ */