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Retime PTW response valid bits

It's not just to save the gate delay; it also reduces wire delay by
allowing the flops to be closer to their respective TLBs.
This commit is contained in:
Andrew Waterman 2017-03-20 01:30:09 -07:00
parent a03556220c
commit 44ca3b60ab

View File

@ -73,7 +73,7 @@ class PTW(n: Int)(implicit p: Parameters) extends CoreModule()(p) {
val state = Reg(init=s_ready)
val count = Reg(UInt(width = log2Up(pgLevels)))
val s1_kill = Reg(next = Bool(false))
val resp_valid = Reg(next = Bool(false))
val resp_valid = Reg(next = Vec.fill(io.requestor.size)(Bool(false)))
val exception = Reg(next = io.mem.xcpt.pf.ld)
val r_req = Reg(new PTWReq)
@ -132,7 +132,7 @@ class PTW(n: Int)(implicit p: Parameters) extends CoreModule()(p) {
io.mem.invalidate_lr := Bool(false)
for (i <- 0 until io.requestor.size) {
io.requestor(i).resp.valid := resp_valid && (r_req_dest === i)
io.requestor(i).resp.valid := resp_valid(i)
io.requestor(i).resp.bits.pte := r_pte
io.requestor(i).resp.bits.level := count
io.requestor(i).resp.bits.pte.ppn := pte_addr >> pgIdxBits
@ -172,13 +172,13 @@ class PTW(n: Int)(implicit p: Parameters) extends CoreModule()(p) {
count := count + 1
}.otherwise {
state := s_ready
resp_valid := true
resp_valid(r_req_dest) := true
}
}
when (exception) {
r_pte.v := false
state := s_ready
resp_valid := true
resp_valid(r_req_dest) := true
}
}
}