pvm.c

压缩包里面的都是精致的基本C语言小程序

#include <stdio.h>
#include "../lib/error.h"
#include "../lib/hash.h"
#include "../lib/nat.h"
#include "../lib/mystdlib.h"
#include "store.h"
#include "pvm.h"

nat pvmOperand (store st, operand o)
{
  switch (o->kind)
  {
    case PID : 
    {
      nat n = storeLookup (st, (o->u).id);
      return n;
    }
    case PNUM : 
    {
      return (newNat ((o->u).i));
    }
    default: return (newNat (0));
  }
}

void pvmInstruction (store st, instruction i)
{
  switch (i->kind)
  {
    case MOVL:
      {
        nat n1 = pvmOperand (st, i->src);
        storeUpdate (st, i->dst, n1);
        break;
      }
    case ADDL:
      {
        nat n1 = pvmOperand (st, i->src);
        nat n2 = storeLookup (st, i->dst);
        nat n = natAdd (n1, n2);
        storeUpdate (st, i->dst, n);
        break;
      }
    case SUBL:
      {
        nat n1 = pvmOperand (st, i->src);
        nat n2 = storeLookup (st, i->dst);
        nat n = natSub (n2, n1);
        storeUpdate (st, i->dst, n);
        break;
      }
    case MULL:
      {
        nat n1 = pvmOperand (st, i->src);
        nat n2 = storeLookup (st, i->dst);
        nat n = natTimes (n1, n2);
        storeUpdate (st, i->dst, n);
        break;
      }
    case PPRINT:
      {        
        nat n = pvmOperand (st, i->src);
        natOutput (n);
        printf ("\n");
        break;
      }
    case COMMENT:
      {        
        //printf ("DO NOTHING FOR COMMENT\n");
        break;
      }
    default:
      {
        error ("no this case\n");
        break;
      }
  }
}

void pvmProg (pentiumProg p)
{
  printf ("\nPVM starts:\n");
  linkedList l = linkedListGetFirst (p->instructions);
  store st = newStore ();    
  
  while (l)
  {
    pvmInstruction (st, l->data);
    l = l->next;
  }  
  printf ("\nPVM halts\n");
  return;
}