cse.dcf

用Java实现的编译器。把源代码编译成SPARC汇编程序

class Program {

  int ai[1];
  
  int double(int a) {
    return (a*2);
  }
  
  void main() {
    int a, b, c, d, e, f;

    callout("printf","A? ");
    a = callout("readint");

    callout("printf","B? ");
    b = callout("readint");

    callout("printf","C? ");
    c = callout("readint");
    
    d = a + b;
    e = a + b;     // should reuse the previous expression
    f = a + c + b; // could reuse a + b
    
    ai[0] = d;
    e = ai[0]; 	   // could reuse the bounds check

    if (c < 4) {
      a = 3;
      b = double(a);
      c = double(a); // could optimize if it knows double is a pure function
    }

    a = a + b; // can't be optimized

    callout("printf", "a: %d  ", a);
    callout("printf", "b: %d  ", b);
    callout("printf", "c: %d  ", c);
    callout("printf", "d: %d  ", d);
    callout("printf", "e: %d\n\n", e);

  }
}