rdr1
pcb->pcb_dbregs->dr[1] = rdr1();
if (rdr1() < (vaddr_t)VM_MAXUSER_ADDRESS)
initdbstate.dr[1] = rdr1();
cpudata->drs[NVMM_X64_DR_DR1] = rdr1();
cpudata->drs[NVMM_X64_DR_DR1] = rdr1();