smiOop.hpp

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/* Copyright 1994, 1995 LongView Technologies L.L.C. $Revision: 1.11 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
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// 0, 1 in smiOop format

# define smiOop_zero  smiOop((0L << Tag_Size) + Int_Tag)
# define smiOop_one   smiOop((1L << Tag_Size) + Int_Tag)

// minimum and maximum smiOops
# define smi_min  (-(1 << (BitsPerWord - 3)))      // -2^29
# define smi_max  ( (1 << (BitsPerWord - 3)) - 1)  // +2^29 - 1

# define smiOop_min   smiOop((smi_min << Tag_Size) + Int_Tag)
# define smiOop_max   smiOop((smi_max << Tag_Size) + Int_Tag)

class smiOopDesc: public oopDesc {
 public:
  // constructors
  friend smiOop as_smiOop(smi value);

  // accessors
  // %note: value() depends on an arithmetic shift to preserve sign.
  smi value()      const { return smi(this) >> Tag_Size; }
  
  smi identity_hash() const { return value(); }
  
  // arithmetic
  smiOop increment() { return smiOop(smi(this) + smi(smiOop_one)); }
  smiOop decrement() { return smiOop(smi(this) - smi(smiOop_one)); }
  
  // printing
  void print_on(outputStream* st);

  // operations provided for the optimizing compiler.
  friend smiOop as_byte_count_smiOop(smi value) {
    assert(lowerBits(value, Tag_Size) == 0, "not a legal byte count");
    return smiOop(value + Int_Tag); }

  smi byte_count() const { return smi(this) - Int_Tag;   }
};

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