8204210: Implementation: JEP 333: ZGC: A Scalable Low-Latency Garbage Collector (Experimental)
Reviewed-by: pliden, stefank, eosterlund, ehelin, sjohanss, rbackman, coleenp, ihse, jgeorge, lmesnik, rkennke
Contributed-by: per.liden@oracle.com, stefan.karlsson@oracle.com, erik.osterlund@oracle.com, mikael.gerdin@oracle.com, kim.barrett@oracle.com, nils.eliasson@oracle.com, rickard.backman@oracle.com, rwestrel@redhat.com, coleen.phillimore@oracle.com, robbin.ehn@oracle.com, gerard.ziemski@oracle.com, hugh.wilkinson@intel.com, sandhya.viswanathan@intel.com, bill.npo.wheeler@intel.com, vinay.k.awasthi@intel.com, yasuenag@gmail.com
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package sun.jvm.hotspot.gc.z;
import sun.jvm.hotspot.debugger.Address;
import sun.jvm.hotspot.debugger.OopHandle;
import sun.jvm.hotspot.runtime.VM;
class ZOop {
private static final long MSB = ~0L ^ (~0L >>> 1);
private static Address msbAddress() {
return VM.getVM().getUniverse().heap().start().orWithMask(MSB).andWithMask(MSB);
}
static Address to_address(long value) {
// If the value of an Address becomes 0, null is returned instead of an Address.
// Start with a one-bit address and as a last step, remove that bit.
Address oneAddress = msbAddress();
return oneAddress.orWithMask(value).xorWithMask(ZAddress.as_long(oneAddress));
}
static Address to_address(OopHandle oop) {
return to_address(ZAddress.as_long(oop));
}
}