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ameliorate DTLB kill->rdy critical path

This commit is contained in:
Andrew Waterman 2012-08-06 17:05:05 -07:00
parent b94e6915ab
commit e9c35b4923

View File

@ -125,11 +125,11 @@ class rocketDTLB(entries: Int) extends Component
val plru = new PseudoLRU(entries) val plru = new PseudoLRU(entries)
val repl_waddr = Mux(has_invalid_entry, invalid_entry, plru.replace).toUFix; val repl_waddr = Mux(has_invalid_entry, invalid_entry, plru.replace).toUFix;
val lookup = (state === s_ready) && r_cpu_req_val && !io.cpu_req.bits.kill && (req_load || req_store || req_amo || req_pf); val lookup = (state === s_ready) && status_vm && r_cpu_req_val && (req_load || req_store || req_amo || req_pf);
val lookup_hit = lookup && tag_hit; val lookup_hit = lookup && tag_hit;
val lookup_miss = lookup && !tag_hit; val lookup_miss = lookup && !tag_hit;
val tlb_hit = status_vm && lookup_hit; val tlb_hit = !io.cpu_req.bits.kill && lookup_hit;
val tlb_miss = status_vm && lookup_miss; val tlb_miss = !io.cpu_req.bits.kill && lookup_miss;
// currently replace TLB entries in LIFO order // currently replace TLB entries in LIFO order
// TODO: implement LRU replacement policy // TODO: implement LRU replacement policy
@ -154,7 +154,7 @@ class rocketDTLB(entries: Int) extends Component
io.cpu_resp.xcpt_st := store_fault_common && (req_store || req_amo) io.cpu_resp.xcpt_st := store_fault_common && (req_store || req_amo)
io.cpu_resp.xcpt_pf := load_fault_common && req_pf io.cpu_resp.xcpt_pf := load_fault_common && req_pf
io.cpu_req.ready := (state === s_ready) && !tlb_miss; io.cpu_req.ready := (state === s_ready) && !lookup_miss;
io.cpu_resp.miss := tlb_miss; io.cpu_resp.miss := tlb_miss;
io.cpu_resp.ppn := io.cpu_resp.ppn :=
Mux(status_vm, tag_ram(tag_hit_addr), r_cpu_req_vpn(PPN_BITS-1,0)); Mux(status_vm, tag_ram(tag_hit_addr), r_cpu_req_vpn(PPN_BITS-1,0));