+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+ // mmi_ : ld8 st1 shr;; mmi_ : st8 st1 shr;;
+ // mib : mov add br -> mib : ld8 add br
+ // bbb_ : br nop cover;; mbb_ : mov br cover;;
+ //
+ // no one require bsp in r16 if (pKStk) branch is selected.
+(pUStk) st8 [r3]=r22 // save time at leave
+(pUStk) st1 [r18]=r17 // restore current->thread.on_ustack
+ shr.u r18=r19,16 // get byte size of existing "dirty" partition
+ ;;
+ ld8.fill r3=[r16] // deferred
+ LOAD_PHYS_STACK_REG_SIZE(r17)
+(pKStk) br.cond.dpnt skip_rbs_switch
+ mov r16=ar.bsp // get existing backing store pointer
+#else