tag.hpp

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/* Copyright 1994, 1995 LongView Technologies L.L.C. $Revision: 1.4 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
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const int Int_Tag      = 0;
const int Mem_Tag      = 1;
const int Mark_Tag     = 3;
const int Mark_Tag_Bit = 2;     // (oop & Mark_Tag_Bit) != 0  --> oop is a markOop

const int Tag_Size     = 2;
const int Tag_Mask     = nthMask(Tag_Size);
const int Num_Tags     = nthBit(Tag_Size);

# define clearTag(oop)  (int(oop) & ~Tag_Mask)

inline int byteOffset(int offset) {
  // Computes the byte offset from the beginning of an oop
  assert(offset >= 0, "bad offset");
  return offset * sizeof(oop) - Mem_Tag;
}

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