post-scarcity/src/memory/stack.h

72 lines
2.3 KiB
C

/**
* stack.h
*
* The Lisp evaluation stack.
*
* Stack frames could be implemented in cons space; indeed, the stack
* could simply be an assoc list consed onto the front of the environment.
* But such a stack would be costly to search. The design sketched here,
* with stack frames as special objects, SHOULD be substantially more
* efficient, but does imply we need to generalise the idea of cons pages
* with freelists to a more general 'equal sized object pages', so that
* allocating/freeing stack frames can be more efficient.
*
* Stack frames are not yet a first class object; they have no VECP pointer
* in cons space.
*
* (c) 2017 Simon Brooke <simon@journeyman.cc>
* Licensed under GPL version 2.0, or, at your option, any later version.
*/
#include "consspaceobject.h"
#include "conspage.h"
#ifndef __stack_h
#define __stack_h
/**
* macros for the tag of a stack frame.
*/
#define STACKFRAMETAG "STAK"
#define STACKFRAMETV 1262572627
/**
* is this vector-space object a stack frame?
*/
#define stackframep(vso)(((struct vector_space_object *)vso)->header.tag.value == STACKFRAMETV)
/**
* set a register in a stack frame. Alwaye use this macro to do so,
• because that way we can be sure the inc_ref happens!
*/
//#define set_reg(frame,register,value){frame->arg[register]=value; inc_ref(value);}
void set_reg(struct stack_frame * frame, int reg, struct cons_pointer value);
struct stack_frame *get_stack_frame( struct cons_pointer pointer );
struct cons_pointer make_empty_frame( struct cons_pointer previous );
struct cons_pointer make_stack_frame( struct cons_pointer previous,
struct cons_pointer args,
struct cons_pointer env );
void free_stack_frame( struct stack_frame *frame );
void dump_frame( FILE * output, struct cons_pointer pointer );
void dump_stack_trace( FILE * output, struct cons_pointer frame_pointer );
struct cons_pointer fetch_arg( struct stack_frame *frame, unsigned int n );
struct cons_pointer make_special_frame( struct cons_pointer previous,
struct cons_pointer args,
struct cons_pointer env );
/*
* struct stack_frame is defined in consspaceobject.h to break circularity
* TODO: refactor.
*/
#endif