149 lines
2.4 KiB
C
149 lines
2.4 KiB
C
#include "lisp.h"
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struct cell *free_cells, *gc_block_start, *gc_block_end;
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int64_t left_to_take;
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int64_t cells_remaining()
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{
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return left_to_take;
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}
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void update_remaining()
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{
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int64_t count = 0;
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struct cell* i = free_cells;
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while(NULL != i)
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{
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count = count + 1;
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i = i->cdr;
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}
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left_to_take = count;
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}
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void reclaim_marked()
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{
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struct cell* i;
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for(i= gc_block_start; i < gc_block_end; i = i + 1)
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{
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if(i->type & MARKED)
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{
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i->type = FREE;
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i->car = NULL;
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i->cdr = free_cells;
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i->env = NULL;
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free_cells = i;
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}
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}
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}
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void mark_all_cells()
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{
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struct cell* i;
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for(i= gc_block_start; i < gc_block_end; i = i + 1)
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{
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/* if not in the free list */
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if(!(i->type & FREE))
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{
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/* Mark it */
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i->type = i->type | MARKED;
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}
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}
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}
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void unmark_cells(struct cell* list)
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{
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for(; NULL != list; list = list->cdr)
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{
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list->type = list->type & ~MARKED;
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if((list->type & CONS)|| list->type & PROC )
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{
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unmark_cells(list->car);
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}
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}
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}
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void garbage_collect()
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{
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mark_all_cells();
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unmark_cells(all_symbols);
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unmark_cells(top_env);
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unmark_cells(nil);
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unmark_cells(tee);
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unmark_cells(quote);
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unmark_cells(s_if);
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unmark_cells(s_lambda);
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unmark_cells(s_define);
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unmark_cells(s_setb);
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unmark_cells(s_cond);
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unmark_cells(s_begin);
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reclaim_marked();
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update_remaining();
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}
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void garbage_init()
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{
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int number_of_Cells = 1000000;
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gc_block_start = calloc(number_of_Cells + 1, sizeof(cell));
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gc_block_end = gc_block_start + number_of_Cells;
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free_cells = NULL;
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garbage_collect();
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}
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struct cell* pop_cons()
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{
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if(NULL == free_cells)
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{
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printf("OOOPS we ran out of cells");
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exit(EXIT_FAILURE);
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}
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struct cell* i;
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i = free_cells;
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free_cells = i->cdr;
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i->cdr = NULL;
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left_to_take = left_to_take - 1;
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return i;
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}
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struct cell* make_int(int a)
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{
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struct cell* c = pop_cons();
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c->type = INT;
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c->value = a;
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return c;
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}
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struct cell* make_sym(char* name)
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{
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struct cell* c = pop_cons();
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c->type = SYM;
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c->string = name;
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return c;
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}
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struct cell* make_cons(struct cell* a, struct cell* b)
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{
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struct cell* c = pop_cons();
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c->type = CONS;
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c->car = a;
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c->cdr = b;
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return c;
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}
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struct cell* make_proc(struct cell* a, struct cell* b, struct cell* env)
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{
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struct cell* c = pop_cons();
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c->type = PROC;
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c->car = a;
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c->cdr = b;
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c->env = env;
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return c;
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}
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struct cell* make_prim(void* fun)
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{
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struct cell* c = pop_cons();
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c->type = PRIMOP;
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c->function = fun;
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return c;
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}
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