XmGetRegisterAddress

INT64 __fastcall XmGetRegisterAddress(INT64 a1, UINT64 a2){
  if( (unsigned int)a2 < 4 || *(_DWORD *)(a1 + 120) )
    return a1 + 4 * ((unsigned int)a2 + 6i64);
  else
    return a1 + 25 + 4i64 * (unsigned int)(a2 - 4);
}

Referenced by:

XmEvaluateAddressSpecifier
XmGroup1General
XmMoveGeneral
XmMoveRegImmediate