rdr0
pcb->pcb_dbregs->dr[0] = rdr0();
if (rdr0() < (vaddr_t)VM_MAXUSER_ADDRESS)
initdbstate.dr[0] = rdr0();
cpudata->drs[NVMM_X64_DR_DR0] = rdr0();
cpudata->drs[NVMM_X64_DR_DR0] = rdr0();