/*
 * SECD-like bytecode interpreter in C
 * Pedro Vasconcelos, 2013
 */
#include <stdint.h>

/* opcodes 
 */
#define HALT    0
#define LDC     1
#define LD      2
#define ADD     3
#define SUB     4
#define MUL     5
#define SEL     6
#define LDF     7
#define LDRF    8
#define AP      9
#define RTN     10
#define JOIN    11

/* values: 
   either an int or a pointer
 */
typedef intptr_t value_t;

/* environments:
   single linked list of values 
*/
typedef struct _env_node_t {
  value_t elm;
  struct _env_node_t *next;
} env_node_t;

typedef env_node_t *env_t;

/* closures 
*/
typedef struct {
  int pc;      // program counter
  env_t env;   // environment
} closure_t;


/* dump entry
   pair of program counter and environment pointer
 */
typedef struct {
  int pc;
  env_t env;
} dump_t;

/* global segment sizes 
 */
#define CODE_MAX  1000
#define STACK_MAX 1000
#define DUMP_MAX  1000