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rocket-chip/rocket/src/main/scala/nbdcache.scala

1207 lines
48 KiB
Scala
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package Top {
import Chisel._
import Node._;
import Constants._;
import scala.math._;
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class ReplacementWayGen extends Component {
val io = new Bundle {
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val way_en = Bits(width = width, dir = INPUT)
val way_id = UFix(width = log2up(NWAYS), dir = OUTPUT)
}
}
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class RandomReplacementWayGen extends ReplacementWayGen() {
val width = max(6,log2up(NWAYS))
val lfsr = Reg(resetVal = UFix(1, width))
when (io.way_en.orR) { lfsr <== Cat(lfsr(0)^lfsr(2)^lfsr(3)^lfsr(5), lfsr(width-1,1)) }
//TODO: Actually limit selection based on which ways are available (io.ways_en)
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io.way_id := lfsr(log2up(NWAYS)-1,0).toUFix
}
class StoreMaskGen extends Component {
val io = new Bundle {
val typ = Bits(3, INPUT)
val addr = Bits(3, INPUT)
val wmask = Bits(8, OUTPUT)
}
val word = (io.typ === MT_W) || (io.typ === MT_WU)
val half = (io.typ === MT_H) || (io.typ === MT_HU)
val byte = (io.typ === MT_B) || (io.typ === MT_BU)
io.wmask := Mux(byte, Bits( 1,1) << io.addr(2,0).toUFix,
Mux(half, Bits( 3,2) << Cat(io.addr(2,1), Bits(0,1)).toUFix,
Mux(word, Bits( 15,4) << Cat(io.addr(2), Bits(0,2)).toUFix,
Bits(255,8))));
}
class StoreDataGen extends Component {
val io = new Bundle {
val typ = Bits(3, INPUT)
val din = Bits(64, INPUT)
val dout = Bits(64, OUTPUT)
}
val word = (io.typ === MT_W) || (io.typ === MT_WU)
val half = (io.typ === MT_H) || (io.typ === MT_HU)
val byte = (io.typ === MT_B) || (io.typ === MT_BU)
io.dout := Mux(byte, Fill(8, io.din( 7,0)),
Mux(half, Fill(4, io.din(15,0)),
Mux(word, Fill(2, io.din(31,0)),
io.din)))
}
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// this currently requires that CPU_DATA_BITS == 64
class LoadDataGen extends Component {
val io = new Bundle {
val typ = Bits(3, INPUT)
val addr = Bits(log2up(MEM_DATA_BITS/8), INPUT)
val din = Bits(MEM_DATA_BITS, INPUT)
val dout = Bits(64, OUTPUT)
val r_dout = Bits(64, OUTPUT)
val r_dout_subword = Bits(64, OUTPUT)
}
val sext = (io.typ === MT_B) || (io.typ === MT_H) ||
(io.typ === MT_W) || (io.typ === MT_D)
val word = (io.typ === MT_W) || (io.typ === MT_WU)
val half = (io.typ === MT_H) || (io.typ === MT_HU)
val byte = (io.typ === MT_B) || (io.typ === MT_BU)
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val shifted = io.din >> Cat(io.addr(io.addr.width-1,2), Bits(0, 5)).toUFix
val extended =
Mux(word, Cat(Fill(32, sext & shifted(31)), shifted(31,0)), shifted)
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val r_extended = Reg(extended)
val r_sext = Reg(sext)
val r_half = Reg(half)
val r_byte = Reg(byte)
val r_addr = Reg(io.addr)
val shifted_subword = r_extended >> Cat(r_addr(1,0), Bits(0, 3)).toUFix
val extended_subword =
Mux(r_byte, Cat(Fill(56, r_sext & shifted_subword( 7)), shifted_subword( 7,0)),
Mux(r_half, Cat(Fill(48, r_sext & shifted_subword(15)), shifted_subword(15,0)),
shifted_subword))
io.dout := extended
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io.r_dout := r_extended
io.r_dout_subword := extended_subword
}
class RPQEntry extends Bundle {
val offset = Bits(width = OFFSET_BITS)
val cmd = Bits(width = 4)
val typ = Bits(width = 3)
val sdq_id = UFix(width = log2up(NSDQ))
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val tag = Bits(width = DCACHE_TAG_BITS)
}
class Replay extends Bundle {
val idx = Bits(width = IDX_BITS)
val offset = Bits(width = OFFSET_BITS)
val cmd = Bits(width = 4)
val typ = Bits(width = 3)
val sdq_id = UFix(width = log2up(NSDQ))
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val tag = Bits(width = DCACHE_TAG_BITS)
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val way_id = UFix(width = log2up(NWAYS))
}
class DataReq extends Bundle {
val idx = Bits(width = IDX_BITS)
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val offset = Bits(width = OFFSET_BITS)
val cmd = Bits(width = 4)
val typ = Bits(width = 3)
val data = Bits(width = CPU_DATA_BITS)
}
class DataArrayReq extends Bundle {
val idx = Bits(width = IDX_BITS)
val offset = Bits(width = log2up(REFILL_CYCLES))
val rw = Bool()
val wmask = Bits(width = MEM_DATA_BITS/8)
val data = Bits(width = MEM_DATA_BITS)
}
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class DataArrayArrayReq extends Bundle {
val inner_req = new DataArrayReq()
val way_en = Bits(width = NWAYS)
}
class MemReq extends Bundle {
val rw = Bool()
val addr = UFix(width = PPN_BITS+IDX_BITS)
val tag = Bits(width = DMEM_TAG_BITS)
}
class WritebackReq extends Bundle {
val ppn = Bits(width = PPN_BITS)
val idx = Bits(width = IDX_BITS)
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val way_id = UFix(width = log2up(NWAYS))
}
class MetaData extends Bundle {
val valid = Bool()
val dirty = Bool()
val tag = Bits(width = PPN_BITS)
}
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class MetaArrayReq extends Bundle {
val idx = Bits(width = IDX_BITS)
val rw = Bool()
val data = new MetaData()
}
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class MetaArrayArrayReq extends Bundle {
val inner_req = new MetaArrayReq()
val way_en = Bits(width = NWAYS)
}
class MSHR(id: Int) extends Component {
val io = new Bundle {
val req_pri_val = Bool(INPUT)
val req_pri_rdy = Bool(OUTPUT)
val req_sec_val = Bool(INPUT)
val req_sec_rdy = Bool(OUTPUT)
val req_ppn = Bits(PPN_BITS, INPUT)
val req_idx = Bits(IDX_BITS, INPUT)
val req_offset = Bits(OFFSET_BITS, INPUT)
val req_cmd = Bits(4, INPUT)
val req_type = Bits(3, INPUT)
val req_sdq_id = UFix(log2up(NSDQ), INPUT)
val req_tag = Bits(DCACHE_TAG_BITS, INPUT)
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val req_way_id = UFix(log2up(NWAYS),INPUT)
val idx_match = Bool(OUTPUT)
val idx = Bits(IDX_BITS, OUTPUT)
val tag = Bits(PPN_BITS, OUTPUT)
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val way_id = Bits(log2up(NWAYS), OUTPUT)
val mem_resp_val = Bool(INPUT)
val mem_req = (new ioDecoupled) { new MemReq() }.flip
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val meta_req = (new ioDecoupled) { new MetaArrayArrayReq() }.flip
val replay = (new ioDecoupled) { new Replay() }.flip
}
val valid = Reg(resetVal = Bool(false))
val dirty = Reg { Bool() }
val requested = Reg { Bool() }
val refilled = Reg { Bool() }
val ppn = Reg { Bits() }
val idx_ = Reg { Bits() }
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val way_id_ = Reg { Bits() }
val req_load = (io.req_cmd === M_XRD) || (io.req_cmd === M_PFR)
val req_use_rpq = (io.req_cmd != M_PFR) && (io.req_cmd != M_PFW)
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val next_dirty = dirty || io.req_sec_val && io.req_sec_rdy && !req_load
val sec_rdy = io.idx_match && !refilled && (dirty || !requested || req_load)
val rpq = (new queueSimplePF(NRPQ)) { new RPQEntry() }
rpq.io.q_reset := Bool(false)
rpq.io.enq.valid := (io.req_pri_val && io.req_pri_rdy || io.req_sec_val && sec_rdy) && req_use_rpq
rpq.io.enq.bits.offset := io.req_offset
rpq.io.enq.bits.cmd := io.req_cmd
rpq.io.enq.bits.typ := io.req_type
rpq.io.enq.bits.sdq_id := io.req_sdq_id
rpq.io.enq.bits.tag := io.req_tag
rpq.io.deq.ready := io.replay.ready && refilled
when (io.req_pri_val && io.req_pri_rdy) {
valid <== Bool(true)
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dirty <== !req_load
requested <== Bool(false)
refilled <== Bool(false)
ppn <== io.req_ppn
idx_ <== io.req_idx
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way_id_ <== io.req_way_id
}
when (io.mem_req.valid && io.mem_req.ready) {
requested <== Bool(true)
}
when (io.mem_resp_val) {
refilled <== Bool(true)
}
when (io.meta_req.valid && io.meta_req.ready) {
valid <== Bool(false)
}
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otherwise {
dirty <== next_dirty
}
io.idx_match := valid && (idx_ === io.req_idx)
io.idx := idx_
io.tag := ppn
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io.way_id := way_id_
io.req_pri_rdy := !valid
io.req_sec_rdy := sec_rdy && rpq.io.enq.ready
io.meta_req.valid := valid && refilled && !rpq.io.deq.valid
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io.meta_req.bits.inner_req.rw := Bool(true)
io.meta_req.bits.inner_req.idx := idx_
io.meta_req.bits.inner_req.data.valid := Bool(true)
io.meta_req.bits.inner_req.data.dirty := dirty
io.meta_req.bits.inner_req.data.tag := ppn
io.meta_req.bits.way_en := UFixToOH(way_id_.toUFix, NWAYS)
io.mem_req.valid := valid && !requested
//io.mem_req.bits.itm := next_dirty
io.mem_req.bits.rw := Bool(false)
io.mem_req.bits.addr := Cat(ppn, idx_).toUFix
io.mem_req.bits.tag := Bits(id)
io.replay.valid := rpq.io.deq.valid && refilled
io.replay.bits.idx := idx_
io.replay.bits.tag := rpq.io.deq.bits.tag
io.replay.bits.offset := rpq.io.deq.bits.offset
io.replay.bits.cmd := rpq.io.deq.bits.cmd
io.replay.bits.typ := rpq.io.deq.bits.typ
io.replay.bits.sdq_id := rpq.io.deq.bits.sdq_id
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io.replay.bits.way_id := way_id_.toUFix
}
class MSHRFile extends Component {
val io = new Bundle {
val req_val = Bool(INPUT)
val req_rdy = Bool(OUTPUT)
val req_ppn = Bits(PPN_BITS, INPUT)
val req_idx = Bits(IDX_BITS, INPUT)
val req_offset = Bits(OFFSET_BITS, INPUT)
val req_cmd = Bits(4, INPUT)
val req_type = Bits(3, INPUT)
val req_tag = Bits(DCACHE_TAG_BITS, INPUT)
val req_sdq_id = UFix(log2up(NSDQ), INPUT)
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val req_way_id = UFix(log2up(NWAYS), INPUT)
val mem_resp_val = Bool(INPUT)
val mem_resp_tag = Bits(DMEM_TAG_BITS, INPUT)
val mem_resp_idx = Bits(IDX_BITS, OUTPUT)
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val mem_resp_way_id = UFix(log2up(NWAYS), OUTPUT)
val fence_rdy = Bool(OUTPUT)
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val mem_req = (new ioDecoupled) { new MemReq() }.flip()
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val meta_req = (new ioDecoupled) { new MetaArrayArrayReq() }.flip()
val replay = (new ioDecoupled) { new Replay() }.flip()
}
val tag_mux = new Mux1H(NMSHR, PPN_BITS)
val mem_resp_idx_mux = new Mux1H(NMSHR, IDX_BITS)
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val mem_resp_way_id_mux = new Mux1H(NMSHR, log2up(NWAYS))
val meta_req_arb = (new Arbiter(NMSHR)) { new MetaArrayArrayReq() }
val mem_req_arb = (new Arbiter(NMSHR)) { new MemReq() }
val replay_arb = (new Arbiter(NMSHR)) { new Replay() }
val alloc_arb = (new Arbiter(NMSHR)) { Bool() }
val tag_match = tag_mux.io.out === io.req_ppn
var idx_match = Bool(false)
var pri_rdy = Bool(false)
var fence = Bool(false)
var sec_rdy = Bool(false)
for (i <- 0 to NMSHR-1) {
val mshr = new MSHR(i)
tag_mux.io.sel(i) := mshr.io.idx_match
tag_mux.io.in(i) := mshr.io.tag
alloc_arb.io.in(i).valid := mshr.io.req_pri_rdy
mshr.io.req_pri_val := alloc_arb.io.in(i).ready
mshr.io.req_sec_val := io.req_val && tag_match
mshr.io.req_ppn := io.req_ppn
mshr.io.req_tag := io.req_tag
mshr.io.req_idx := io.req_idx
mshr.io.req_offset := io.req_offset
mshr.io.req_cmd := io.req_cmd
mshr.io.req_type := io.req_type
mshr.io.req_sdq_id := io.req_sdq_id
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mshr.io.req_way_id := io.req_way_id
mshr.io.meta_req <> meta_req_arb.io.in(i)
mshr.io.mem_req <> mem_req_arb.io.in(i)
mshr.io.replay <> replay_arb.io.in(i)
val mem_resp_val = io.mem_resp_val && (UFix(i) === io.mem_resp_tag)
mshr.io.mem_resp_val := mem_resp_val
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mem_resp_idx_mux.io.sel(i) := (UFix(i) === io.mem_resp_tag)
mem_resp_idx_mux.io.in(i) := mshr.io.idx
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mem_resp_way_id_mux.io.sel(i) := (UFix(i) === io.mem_resp_tag)
mem_resp_way_id_mux.io.in(i) := mshr.io.way_id
pri_rdy = pri_rdy || mshr.io.req_pri_rdy
sec_rdy = sec_rdy || mshr.io.req_sec_rdy
fence = fence || !mshr.io.req_pri_rdy
idx_match = idx_match || mshr.io.idx_match
}
alloc_arb.io.out.ready := io.req_val && !idx_match
meta_req_arb.io.out <> io.meta_req
mem_req_arb.io.out <> io.mem_req
replay_arb.io.out <> io.replay
io.req_rdy := Mux(idx_match, tag_match && sec_rdy, pri_rdy)
io.mem_resp_idx := mem_resp_idx_mux.io.out
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io.mem_resp_way_id := mem_resp_way_id_mux.io.out.toUFix
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io.fence_rdy := !fence
}
class ReplayUnit extends Component {
val io = new Bundle {
val sdq_enq = (new ioDecoupled) { Bits(width = CPU_DATA_BITS) }
val sdq_id = UFix(log2up(NSDQ), OUTPUT)
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val way_id = UFix(log2up(NWAYS), OUTPUT)
val replay = (new ioDecoupled) { new Replay() }
val data_req = (new ioDecoupled) { new DataReq() }.flip()
val cpu_resp_val = Bool(OUTPUT)
val cpu_resp_tag = Bits(DCACHE_TAG_BITS, OUTPUT)
}
val sdq_val = Reg(resetVal = UFix(0, NSDQ))
val sdq_allocator = new priorityEncoder(NSDQ)
sdq_allocator.io.in := ~sdq_val
val sdq_alloc_id = sdq_allocator.io.out.toUFix
val replay_val = Reg(resetVal = Bool(false))
val replay_retry = replay_val && !io.data_req.ready
replay_val <== io.replay.valid || replay_retry
val rp = Reg { new Replay() }
when (io.replay.valid && io.replay.ready) { rp <== io.replay.bits }
val rp_amo = rp.cmd(3).toBool
val rp_store = (rp.cmd === M_XWR)
val rp_load = (rp.cmd === M_XRD)
val rp_write = rp_store || rp_amo
val rp_read = rp_load || rp_amo
val sdq_ren_new = io.replay.valid && (io.replay.bits.cmd != M_XRD)
val sdq_ren_retry = replay_retry && rp_write
val sdq_ren = sdq_ren_new || sdq_ren_retry
val sdq_wen = io.sdq_enq.valid && io.sdq_enq.ready
val sdq_addr = Mux(sdq_ren_retry, rp.sdq_id, Mux(sdq_ren_new, io.replay.bits.sdq_id, sdq_alloc_id))
val sdq = Mem4(NSDQ, io.sdq_enq.bits)
sdq.setReadLatency(1);
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sdq.setTarget('inst)
val sdq_dout = sdq.rw(sdq_addr, io.sdq_enq.bits, sdq_wen, cs = sdq_ren || sdq_wen)
val sdq_free = replay_val && !replay_retry && rp_write
sdq_val <== sdq_val & ~(sdq_free.toUFix << rp.sdq_id) | (sdq_wen.toUFix << sdq_alloc_id)
io.sdq_enq.ready := (~sdq_val != UFix(0)) && !sdq_ren
io.sdq_id := sdq_alloc_id
io.replay.ready := !replay_retry
io.data_req.valid := replay_val
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io.way_id := rp.way_id
io.data_req.bits.idx := rp.idx
io.data_req.bits.offset := rp.offset
io.data_req.bits.cmd := rp.cmd
io.data_req.bits.typ := rp.typ
io.data_req.bits.data := sdq_dout
io.cpu_resp_val := Reg(replay_val && !replay_retry && rp_read, resetVal = Bool(false))
io.cpu_resp_tag := Reg(rp.tag)
}
class WritebackUnit extends Component {
val io = new Bundle {
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val req = (new ioDecoupled) { new WritebackReq() }
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val data_req = (new ioDecoupled) { new DataArrayArrayReq() }.flip()
val data_resp = Bits(MEM_DATA_BITS, INPUT)
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val refill_req = (new ioDecoupled) { new MemReq() }
val mem_req = (new ioDecoupled) { new MemReq() }.flip()
val mem_req_data = Bits(MEM_DATA_BITS, OUTPUT)
}
val wbq = (new queueSimplePF(REFILL_CYCLES)) { Bits(width = MEM_DATA_BITS) }
val valid = Reg(resetVal = Bool(false))
val cnt = Reg() { UFix(width = log2up(REFILL_CYCLES+1)) }
val addr = Reg() { new WritebackReq() }
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// don't allow memory requests to bypass conflicting writebacks.
// also don't allow a refill request once a writeback has started.
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// TODO: turn this into a victim buffer.
val block_refill = valid && ((io.refill_req.bits.addr(IDX_BITS-1,0) === addr.idx) || (cnt === UFix(REFILL_CYCLES)))
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val refill_val = io.refill_req.valid && !block_refill
wbq.io.q_reset := Bool(false)
wbq.io.enq.valid := valid && Reg(io.data_req.valid && io.data_req.ready)
wbq.io.enq.bits := io.data_resp
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wbq.io.deq.ready := io.mem_req.ready && !refill_val && (cnt === UFix(REFILL_CYCLES))
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when (io.req.valid && io.req.ready) { valid <== Bool(true); cnt <== UFix(0); addr <== io.req.bits }
when (io.data_req.valid && io.data_req.ready) { cnt <== cnt + UFix(1) }
when ((cnt === UFix(REFILL_CYCLES)) && !wbq.io.deq.valid) { valid <== Bool(false) }
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io.req.ready := !valid
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io.data_req.valid := valid && (cnt < UFix(REFILL_CYCLES))
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io.data_req.bits.way_en := UFixToOH(addr.way_id, NWAYS)
io.data_req.bits.inner_req.idx := addr.idx
io.data_req.bits.inner_req.offset := cnt
io.data_req.bits.inner_req.rw := Bool(false)
io.data_req.bits.inner_req.wmask := Bits(0)
io.data_req.bits.inner_req.data := Bits(0)
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io.refill_req.ready := io.mem_req.ready && !block_refill
io.mem_req.valid := refill_val || wbq.io.deq.valid && (cnt === UFix(REFILL_CYCLES))
io.mem_req.bits.rw := !refill_val
io.mem_req.bits.addr := Mux(refill_val, io.refill_req.bits.addr, Cat(addr.ppn, addr.idx).toUFix)
io.mem_req.bits.tag := io.refill_req.bits.tag
io.mem_req_data := wbq.io.deq.bits
}
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class FlushUnit(lines: Int) extends Component {
val io = new Bundle {
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val req = (new ioDecoupled) { Bits(width = DCACHE_TAG_BITS) }
val resp = (new ioDecoupled) { Bits(width = DCACHE_TAG_BITS) }.flip()
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val meta_req = (new ioDecoupled) { new MetaArrayArrayReq() }.flip()
val meta_resp = (new MetaData).asInput()
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val wb_req = (new ioDecoupled) { new WritebackReq() }.flip()
}
val s_reset :: s_ready :: s_meta_read :: s_meta_wait :: s_meta_write :: s_done :: Nil = Enum(6) { UFix() }
val state = Reg(resetVal = s_reset)
val tag = Reg() { Bits() }
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val idx_cnt = Reg(resetVal = UFix(0, log2up(lines)))
val next_idx_cnt = idx_cnt + UFix(1)
val way_cnt = Reg(resetVal = UFix(0, log2up(NWAYS)))
val next_way_cnt = way_cnt + UFix(1)
switch (state) {
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is(s_reset) {
when (io.meta_req.ready) {
state <== Mux(~way_cnt === UFix(0) && ~idx_cnt === UFix(0), s_ready, s_reset);
when (~way_cnt === UFix(0)) { idx_cnt <== next_idx_cnt };
way_cnt <== next_way_cnt;
}
}
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is(s_ready) { when (io.req.valid) { state <== s_meta_read; tag <== io.req.bits } }
is(s_meta_read) { when (io.meta_req.ready) { state <== s_meta_wait } }
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is(s_meta_wait) { state <== Mux(io.meta_resp.valid && io.meta_resp.dirty && !io.wb_req.ready, s_meta_read, s_meta_write) }
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is(s_meta_write) { when (io.meta_req.ready) { state <== Mux(~idx_cnt === UFix(0), s_done, s_meta_read); idx_cnt <== next_idx_cnt } }
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is(s_done) { when (io.resp.ready) { state <== s_ready } }
}
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io.req.ready := state === s_ready
io.resp.valid := state === s_done
io.resp.bits := tag
io.meta_req.valid := (state === s_meta_read) || (state === s_meta_write) || (state === s_reset)
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io.meta_req.bits.way_en := UFixToOH(way_cnt, NWAYS)
io.meta_req.bits.inner_req.idx := idx_cnt
io.meta_req.bits.inner_req.rw := (state === s_meta_write) || (state === s_reset)
io.meta_req.bits.inner_req.data.valid := Bool(false)
io.meta_req.bits.inner_req.data.dirty := Bool(false)
io.meta_req.bits.inner_req.data.tag := UFix(0)
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io.wb_req.valid := state === s_meta_wait
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io.wb_req.bits.ppn := io.meta_resp.tag
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io.wb_req.bits.idx := idx_cnt
io.wb_req.bits.way_id := way_cnt
}
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class MetaDataArrayArray(lines: Int) extends Component {
val io = new Bundle {
val req = (new ioDecoupled) { new MetaArrayArrayReq() }
val resp = Vec(NWAYS){ (new MetaData).asOutput }
val state_req = (new ioDecoupled) { new MetaArrayArrayReq() }
}
val way_arr = List.fill(NWAYS){ new MetaDataArray(lines) }
val tag_ready_arr = Bits(width = NWAYS)
val state_ready_arr = Bits(width = NWAYS)
for(w <- 0 until NWAYS) {
way_arr(w).io.req.bits ^^ io.req.bits.inner_req
way_arr(w).io.req.ready := tag_ready_arr(w)
way_arr(w).io.req.valid := io.req.valid && io.req.bits.way_en(w).toBool
way_arr(w).io.state_req.bits ^^ io.req.bits.inner_req
way_arr(w).io.state_req.ready := state_ready_arr(w)
way_arr(w).io.state_req.valid := io.req.valid && io.req.bits.way_en(w).toBool
io.resp(w) ^^ way_arr(w).io.resp
}
io.req.ready := tag_ready_arr.andR.toBool
io.state_req.ready := state_ready_arr.andR.toBool
}
class MetaDataArray(lines: Int) extends Component {
val io = new Bundle {
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val req = (new ioDecoupled) { new MetaArrayReq() }
val resp = (new MetaData).asOutput()
val state_req = (new ioDecoupled) { new MetaArrayReq() }
}
val vd_array = Mem4(lines, Bits(width = 2))
vd_array.setReadLatency(1);
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val vd_wdata2 = Cat(io.state_req.bits.data.valid, io.state_req.bits.data.dirty)
vd_array.write(io.state_req.bits.idx, vd_wdata2, io.state_req.valid && io.state_req.bits.rw)
val vd_wdata1 = Cat(io.req.bits.data.valid, io.req.bits.data.dirty)
val vd_rdata1 = vd_array.rw(io.req.bits.idx, vd_wdata1, io.req.valid && io.req.bits.rw)
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// don't allow reading and writing of vd_array in same cycle.
// this could be eliminated if the read port were combinational.
val vd_conflict = io.state_req.valid && (io.req.bits.idx === io.state_req.bits.idx)
val tag_array = Mem4(lines, io.resp.tag)
tag_array.setReadLatency(1);
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tag_array.setTarget('inst)
val tag_rdata = tag_array.rw(io.req.bits.idx, io.req.bits.data.tag, io.req.valid && io.req.bits.rw, cs = io.req.valid)
io.resp.valid := vd_rdata1(1).toBool
io.resp.dirty := vd_rdata1(0).toBool
io.resp.tag := tag_rdata
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io.req.ready := !vd_conflict
}
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class DataArrayArray(lines: Int) extends Component {
val io = new Bundle {
val req = (new ioDecoupled) { new DataArrayArrayReq() }
val resp = Vec(NWAYS){ Bits(width = MEM_DATA_BITS, dir = OUTPUT) }
val way_en = Bits(width = NWAYS, dir = OUTPUT)
}
val way_en_ = Reg { Bits() }
when (io.req.valid && io.req.ready) {
way_en_ <== io.req.bits.way_en
}
val way_arr = List.fill(NWAYS){ new DataArray(lines) }
val data_ready_arr = Bits(width = NWAYS)
for(w <- 0 until NWAYS) {
way_arr(w).io.req.bits ^^ io.req.bits.inner_req
way_arr(w).io.req.ready := data_ready_arr(w)
way_arr(w).io.req.valid := io.req.valid && io.req.bits.way_en(w).toBool
io.resp(w) ^^ way_arr(w).io.resp
}
io.way_en := way_en_
io.req.ready := data_ready_arr.andR.toBool
}
class DataArray(lines: Int) extends Component {
val io = new Bundle {
val req = (new ioDecoupled) { new DataArrayReq() }
val resp = Bits(width = MEM_DATA_BITS, dir = OUTPUT)
}
val wmask = FillInterleaved(8, io.req.bits.wmask)
val array = Mem4(lines*REFILL_CYCLES, io.resp)
array.setReadLatency(1);
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array.setTarget('inst)
val addr = Cat(io.req.bits.idx, io.req.bits.offset)
val rdata = array.rw(addr, io.req.bits.data, io.req.valid && io.req.bits.rw, wmask, cs = io.req.valid)
io.resp := rdata
io.req.ready := Bool(true)
}
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class AMOALU extends Component {
val io = new Bundle {
val cmd = Bits(4, INPUT)
val typ = Bits(3, INPUT)
val lhs = UFix(64, INPUT)
val rhs = UFix(64, INPUT)
val out = UFix(64, OUTPUT)
}
val sgned = (io.cmd === M_XA_MIN) || (io.cmd === M_XA_MAX)
val sub = (io.cmd === M_XA_MIN) || (io.cmd === M_XA_MINU) || (io.cmd === M_XA_MAX) || (io.cmd === M_XA_MAXU)
val min = (io.cmd === M_XA_MIN) || (io.cmd === M_XA_MINU)
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val word = (io.typ === MT_W) || (io.typ === MT_WU)
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val adder_out = (Cat(io.lhs, UFix(0,1)).toUFix + Cat(io.rhs ^ Fill(io.rhs.width, sub), sub).toUFix) >> UFix(1)
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val cmp_lhs = Mux(word, io.lhs(31), io.lhs(63))
val cmp_rhs = Mux(word, io.rhs(31), io.rhs(63))
val cmp_diff = Mux(word, adder_out(31), adder_out(63))
val less = Mux(cmp_lhs === cmp_rhs, cmp_diff, Mux(sgned, cmp_lhs, cmp_rhs))
val cmp_out = Mux(min === less, io.lhs, io.rhs)
io.out := Mux(io.cmd === M_XA_ADD, adder_out,
Mux(io.cmd === M_XA_SWAP, io.rhs,
Mux(io.cmd === M_XA_AND, io.lhs & io.rhs,
Mux(io.cmd === M_XA_OR, io.lhs | io.rhs,
/* MIN[U]/MAX[U] */ cmp_out))));
}
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//class HellaCache(lines: Int, ways: Int) extends Component {
//
//}
class HellaCacheDM(lines: Int) extends Component {
val io = new ioDCacheHella()
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val addrbits = PADDR_BITS
val indexbits = log2up(lines)
val offsetbits = OFFSET_BITS
val tagmsb = PADDR_BITS-1
val taglsb = indexbits+offsetbits
val tagbits = tagmsb-taglsb+1
val indexmsb = taglsb-1
val indexlsb = offsetbits
val offsetmsb = indexlsb-1
val offsetlsb = log2up(CPU_DATA_BITS/8)
val ramindexlsb = log2up(MEM_DATA_BITS/8)
val early_nack = Reg { Bool() }
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val r_cpu_req_val_ = Reg(io.cpu.req_val && io.cpu.req_rdy, resetVal = Bool(false))
val r_cpu_req_val = r_cpu_req_val_ && !io.cpu.req_kill && !early_nack
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val r_cpu_req_idx = Reg() { Bits() }
val r_cpu_req_cmd = Reg() { Bits() }
val r_cpu_req_type = Reg() { Bits() }
val r_cpu_req_tag = Reg() { Bits() }
val r_cpu_req_data = Reg() { Bits() }
val p_store_valid = Reg(resetVal = Bool(false))
val p_store_data = Reg() { Bits() }
val p_store_idx = Reg() { Bits() }
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val p_store_cmd = Reg() { Bits() }
val p_store_type = Reg() { Bits() }
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val p_store_way_id = Reg() { Bits() }
val r_replay_amo = Reg(resetVal = Bool(false))
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val req_store = (io.cpu.req_cmd === M_XWR)
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val req_load = (io.cpu.req_cmd === M_XRD)
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val req_amo = io.cpu.req_cmd(3).toBool
val req_read = req_load || req_amo
val req_write = req_store || req_amo
val r_req_load = (r_cpu_req_cmd === M_XRD)
val r_req_store = (r_cpu_req_cmd === M_XWR)
val r_req_flush = (r_cpu_req_cmd === M_FLA)
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val r_req_fence = (r_cpu_req_cmd === M_FENCE)
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val r_req_amo = r_cpu_req_cmd(3).toBool
val r_req_read = r_req_load || r_req_amo
val r_req_write = r_req_store || r_req_amo
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val r_req_readwrite = r_req_read || r_req_write
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// replay unit
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val replayer = new ReplayUnit()
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val replay_amo_val = replayer.io.data_req.valid && replayer.io.data_req.bits.cmd(3).toBool
when (replay_amo_val) {
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r_cpu_req_idx <== Cat(replayer.io.data_req.bits.idx, replayer.io.data_req.bits.offset)
r_cpu_req_cmd <== replayer.io.data_req.bits.cmd
r_cpu_req_type <== replayer.io.data_req.bits.typ
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r_cpu_req_data <== replayer.io.data_req.bits.data
}
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when (io.cpu.req_val) {
r_cpu_req_idx <== io.cpu.req_idx
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r_cpu_req_cmd <== io.cpu.req_cmd
r_cpu_req_type <== io.cpu.req_type
r_cpu_req_tag <== io.cpu.req_tag
when (req_write) {
r_cpu_req_data <== io.cpu.req_data
}
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}
// refill counter
val rr_count = Reg(resetVal = UFix(0, log2up(REFILL_CYCLES)))
val rr_count_next = rr_count + UFix(1)
when (io.mem.resp_val) { rr_count <== rr_count_next }
val misaligned =
(((r_cpu_req_type === MT_H) || (r_cpu_req_type === MT_HU)) && (r_cpu_req_idx(0) != Bits(0))) ||
(((r_cpu_req_type === MT_W) || (r_cpu_req_type === MT_WU)) && (r_cpu_req_idx(1,0) != Bits(0))) ||
((r_cpu_req_type === MT_D) && (r_cpu_req_idx(2,0) != Bits(0)));
io.cpu.xcpt_ma_ld := r_cpu_req_val_ && r_req_read && misaligned
io.cpu.xcpt_ma_st := r_cpu_req_val_ && r_req_write && misaligned
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// tags
val meta = new MetaDataArray(lines)
val meta_arb = (new Arbiter(3)) { new MetaArrayReq() }
meta_arb.io.out <> meta.io.req
// data
val data = new DataArray(lines)
val data_arb = (new Arbiter(5)) { new DataArrayReq() }
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data_arb.io.out <> data.io.req
// writeback unit
val wb = new WritebackUnit
val wb_arb = (new Arbiter(2)) { new WritebackReq() }
wb_arb.io.out <> wb.io.req
wb.io.data_req.bits.inner_req <> data_arb.io.in(3).bits //TODO
wb.io.data_req.ready := data_arb.io.in(3).ready
data_arb.io.in(3).valid := wb.io.data_req.valid
wb.io.data_resp <> data.io.resp
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// cpu tag check
meta_arb.io.in(2).valid := io.cpu.req_val
meta_arb.io.in(2).bits.idx := io.cpu.req_idx(indexmsb,indexlsb)
meta_arb.io.in(2).bits.rw := Bool(false)
meta_arb.io.in(2).bits.data.valid := Bool(false) // don't care
meta_arb.io.in(2).bits.data.dirty := Bool(false) // don't care
meta_arb.io.in(2).bits.data.tag := UFix(0) // don't care
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val early_tag_nack = !meta_arb.io.in(2).ready
val tag_match = meta.io.resp.valid && (meta.io.resp.tag === io.cpu.req_ppn)
val tag_hit = r_cpu_req_val && tag_match
val tag_miss = r_cpu_req_val && !tag_match
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val dirty = meta.io.resp.valid && meta.io.resp.dirty
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// refill response
val block_during_refill = !io.mem.resp_val && (rr_count != UFix(0))
data_arb.io.in(0).valid := io.mem.resp_val || block_during_refill
data_arb.io.in(0).bits.offset := rr_count
data_arb.io.in(0).bits.rw := !block_during_refill
data_arb.io.in(0).bits.wmask := ~UFix(0, MEM_DATA_BITS/8)
data_arb.io.in(0).bits.data := io.mem.resp_data
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// load hits
data_arb.io.in(4).bits.offset := io.cpu.req_idx(offsetmsb,ramindexlsb)
data_arb.io.in(4).bits.idx := io.cpu.req_idx(indexmsb,indexlsb)
data_arb.io.in(4).bits.rw := Bool(false)
data_arb.io.in(4).bits.wmask := UFix(0) // don't care
data_arb.io.in(4).bits.data := io.mem.resp_data // don't care
data_arb.io.in(4).valid := io.cpu.req_val && req_read
val early_load_nack = req_read && !data_arb.io.in(4).ready
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// store hits and AMO hits and misses use a pending store register.
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// we nack new stores if a pending store can't retire for some reason.
// we drain a pending store if the CPU performs a store or a
// conflictig load, or if the cache is idle, or after a miss.
val p_store_idx_match = p_store_valid && (r_cpu_req_idx(indexmsb,indexlsb) === p_store_idx(indexmsb,indexlsb))
val p_store_offset_match = (r_cpu_req_idx(indexlsb-1,offsetlsb) === p_store_idx(indexlsb-1,offsetlsb))
val p_store_match = r_cpu_req_val && r_req_read && p_store_idx_match && p_store_offset_match
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val drain_store_val = (p_store_valid && (!io.cpu.req_val || !req_read || Reg(tag_miss))) || p_store_match
data_arb.io.in(2).bits.offset := p_store_idx(offsetmsb,ramindexlsb)
data_arb.io.in(2).bits.idx := p_store_idx(indexmsb,indexlsb)
data_arb.io.in(2).bits.rw := Bool(true)
data_arb.io.in(2).valid := drain_store_val
val drain_store = drain_store_val && data_arb.io.in(2).ready
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val p_store_rdy = !p_store_valid || drain_store
val p_amo = Reg(tag_hit && r_req_amo && p_store_rdy && !p_store_match || r_replay_amo, resetVal = Bool(false))
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p_store_valid <== !p_store_rdy || (tag_hit && r_req_store) || p_amo
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// writeback
val wb_rdy = wb_arb.io.in(1).ready && !p_store_idx_match
wb_arb.io.in(1).valid := tag_miss && r_req_readwrite && dirty && !p_store_idx_match
wb_arb.io.in(1).bits.ppn := meta.io.resp.tag
wb_arb.io.in(1).bits.idx := r_cpu_req_idx(indexmsb,indexlsb)
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// tag update after a miss or a store to an exclusive clean line.
val clear_valid = tag_miss && r_req_readwrite && meta.io.resp.valid && (!dirty || wb_rdy)
val set_dirty = tag_hit && !meta.io.resp.dirty && r_req_write
meta.io.state_req.valid := clear_valid || set_dirty
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meta.io.state_req.bits.rw := Bool(true)
meta.io.state_req.bits.idx := r_cpu_req_idx(indexmsb,indexlsb)
meta.io.state_req.bits.data.valid := tag_match
meta.io.state_req.bits.data.dirty := tag_match
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// pending store data, also used for AMO RHS
val storegen = new StoreDataGen
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val amoalu = new AMOALU
storegen.io.typ := r_cpu_req_type
storegen.io.din := r_cpu_req_data
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when (p_amo) {
p_store_data <== amoalu.io.out
}
when (tag_hit && r_req_write && p_store_rdy || r_replay_amo) {
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p_store_idx <== r_cpu_req_idx
p_store_type <== r_cpu_req_type
p_store_cmd <== r_cpu_req_cmd
p_store_data <== storegen.io.dout
p_store_way_id <== UFix(0)
}
// miss handling
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val mshr = new MSHRFile()
mshr.io.req_val := tag_miss && r_req_readwrite && (!dirty || wb_rdy) && (!r_req_write || replayer.io.sdq_enq.ready)
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mshr.io.req_ppn := io.cpu.req_ppn
mshr.io.req_idx := r_cpu_req_idx(indexmsb,indexlsb)
mshr.io.req_tag := r_cpu_req_tag
mshr.io.req_offset := r_cpu_req_idx(offsetmsb,0)
mshr.io.req_cmd := r_cpu_req_cmd
mshr.io.req_type := r_cpu_req_type
mshr.io.req_sdq_id := replayer.io.sdq_id
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mshr.io.mem_resp_val := io.mem.resp_val && (~rr_count === UFix(0))
mshr.io.mem_resp_tag := io.mem.resp_tag
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mshr.io.mem_req <> wb.io.refill_req
mshr.io.meta_req.bits.inner_req <> meta_arb.io.in(1).bits //TODO
mshr.io.meta_req.ready := meta_arb.io.in(1).ready
meta_arb.io.in(1).valid := mshr.io.meta_req.valid
mshr.io.replay <> replayer.io.replay
replayer.io.sdq_enq.valid := tag_miss && r_req_write && (!dirty || wb_rdy) && mshr.io.req_rdy
replayer.io.sdq_enq.bits := storegen.io.dout
data_arb.io.in(0).bits.idx := mshr.io.mem_resp_idx
// replays
val replay = replayer.io.data_req.bits
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val stall_replay = r_replay_amo || p_amo || p_store_valid
val replay_val = replayer.io.data_req.valid && !stall_replay
val replay_rdy = data_arb.io.in(1).ready
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data_arb.io.in(1).bits.offset := replay.offset(offsetmsb,ramindexlsb)
data_arb.io.in(1).bits.idx := replay.idx
data_arb.io.in(1).bits.rw := replay.cmd === M_XWR
data_arb.io.in(1).valid := replay_val
replayer.io.data_req.ready := replay_rdy && !stall_replay
r_replay_amo <== replay_amo_val && replay_rdy && !stall_replay
// store write mask generation.
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// assumes store replays are higher-priority than pending stores.
val maskgen = new StoreMaskGen
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val store_offset = Mux(!replay_val, p_store_idx(offsetmsb,0), replay.offset)
maskgen.io.typ := Mux(!replay_val, p_store_type, replay.typ)
maskgen.io.addr := store_offset(offsetlsb-1,0)
val store_wmask_wide = maskgen.io.wmask << Cat(store_offset(ramindexlsb-1,offsetlsb), Bits(0, log2up(CPU_DATA_BITS/8))).toUFix
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val store_data = Mux(!replay_val, p_store_data, replay.data)
val store_data_wide = Fill(MEM_DATA_BITS/CPU_DATA_BITS, store_data)
data_arb.io.in(1).bits.data := store_data_wide
data_arb.io.in(1).bits.wmask := store_wmask_wide
data_arb.io.in(2).bits.data := store_data_wide
data_arb.io.in(2).bits.wmask := store_wmask_wide
// load data subword mux/sign extension.
// subword loads are delayed by one cycle.
val loadgen = new LoadDataGen
val loadgen_use_replay = Reg(replay_val && replay_rdy)
loadgen.io.typ := Mux(loadgen_use_replay, Reg(replay.typ), r_cpu_req_type)
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loadgen.io.addr := Mux(loadgen_use_replay, Reg(replay.offset), r_cpu_req_idx)(ramindexlsb-1,0)
loadgen.io.din := data.io.resp
amoalu.io.cmd := p_store_cmd
amoalu.io.typ := p_store_type
amoalu.io.lhs := loadgen.io.r_dout.toUFix
amoalu.io.rhs := p_store_data.toUFix
early_nack <== early_tag_nack || early_load_nack || r_cpu_req_val && r_req_amo || replay_amo_val || r_replay_amo
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// reset and flush unit
val flusher = new FlushUnit(lines)
val flushed = Reg(resetVal = Bool(true))
val flush_rdy = mshr.io.fence_rdy && wb_rdy && !p_store_valid
flushed <== flushed && !r_cpu_req_val || r_cpu_req_val && r_req_flush && flush_rdy && flusher.io.req.ready
flusher.io.req.valid := r_cpu_req_val && r_req_flush && flush_rdy && !flushed
flusher.io.wb_req <> wb_arb.io.in(0)
flusher.io.meta_req.bits.inner_req <> meta_arb.io.in(0).bits //TODO
flusher.io.meta_req.ready := meta_arb.io.in(0).ready
meta_arb.io.in(0).valid := flusher.io.meta_req.valid
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flusher.io.meta_resp <> meta.io.resp
flusher.io.resp.ready := Bool(true) // we don't respond to flush requests
// we usually nack rather than reporting that the cache is not ready.
// fences and flushes are the exceptions.
val pending_fence = Reg(resetVal = Bool(false))
pending_fence <== (r_cpu_req_val && r_req_fence || pending_fence) && !flush_rdy
val nack_hit = p_store_match || r_req_write && !p_store_rdy
val nack_miss = dirty && !wb_rdy || !mshr.io.req_rdy || r_req_write && !replayer.io.sdq_enq.ready
val nack_flush = !flush_rdy && (r_req_fence || r_req_flush) ||
!flushed && r_req_flush
val nack = early_nack || r_req_readwrite && Mux(tag_match, nack_hit, nack_miss) || nack_flush
io.cpu.req_rdy := flusher.io.req.ready && !(r_cpu_req_val_ && r_req_flush) && !pending_fence
io.cpu.resp_nack := r_cpu_req_val_ && !io.cpu.req_kill && nack
io.cpu.resp_val := (tag_hit && !nack_hit && r_req_read) || replayer.io.cpu_resp_val
io.cpu.resp_replay := replayer.io.cpu_resp_val
io.cpu.resp_miss := tag_miss && !nack_miss && r_req_read
io.cpu.resp_tag := Mux(replayer.io.cpu_resp_val, replayer.io.cpu_resp_tag, r_cpu_req_tag)
io.cpu.resp_data := loadgen.io.dout
io.cpu.resp_data_subword := loadgen.io.r_dout_subword
wb.io.mem_req.ready := io.mem.req_rdy
io.mem.req_val := wb.io.mem_req.valid
io.mem.req_rw := wb.io.mem_req.bits.rw
io.mem.req_wdata := wb.io.mem_req_data
io.mem.req_tag := wb.io.mem_req.bits.tag.toUFix
io.mem.req_addr := wb.io.mem_req.bits.addr
}
class HellaCacheAssoc(lines: Int) extends Component {
val io = new ioDCacheHella()
val addrbits = PADDR_BITS
val indexbits = log2up(lines)
val offsetbits = OFFSET_BITS
val tagmsb = PADDR_BITS-1
val taglsb = indexbits+offsetbits
val tagbits = tagmsb-taglsb+1
val indexmsb = taglsb-1
val indexlsb = offsetbits
val offsetmsb = indexlsb-1
val offsetlsb = log2up(CPU_DATA_BITS/8)
val ramindexlsb = log2up(MEM_DATA_BITS/8)
val early_nack = Reg { Bool() }
val r_cpu_req_val_ = Reg(io.cpu.req_val && io.cpu.req_rdy, resetVal = Bool(false))
val r_cpu_req_val = r_cpu_req_val_ && !io.cpu.req_kill && !early_nack
val r_cpu_req_idx = Reg() { Bits() }
val r_cpu_req_cmd = Reg() { Bits() }
val r_cpu_req_type = Reg() { Bits() }
val r_cpu_req_tag = Reg() { Bits() }
val r_cpu_req_data = Reg() { Bits() }
val p_store_valid = Reg(resetVal = Bool(false))
val p_store_data = Reg() { Bits() }
val p_store_idx = Reg() { Bits() }
val p_store_cmd = Reg() { Bits() }
val p_store_type = Reg() { Bits() }
val p_store_way_id = Reg() { Bits() }
val r_replay_amo = Reg(resetVal = Bool(false))
val req_store = (io.cpu.req_cmd === M_XWR)
val req_load = (io.cpu.req_cmd === M_XRD)
val req_amo = io.cpu.req_cmd(3).toBool
val req_read = req_load || req_amo
val req_write = req_store || req_amo
val r_req_load = (r_cpu_req_cmd === M_XRD)
val r_req_store = (r_cpu_req_cmd === M_XWR)
val r_req_flush = (r_cpu_req_cmd === M_FLA)
val r_req_fence = (r_cpu_req_cmd === M_FENCE)
val r_req_amo = r_cpu_req_cmd(3).toBool
val r_req_read = r_req_load || r_req_amo
val r_req_write = r_req_store || r_req_amo
val r_req_readwrite = r_req_read || r_req_write
// replay unit
val replayer = new ReplayUnit()
val replay_amo_val = replayer.io.data_req.valid && replayer.io.data_req.bits.cmd(3).toBool
when (replay_amo_val) {
r_cpu_req_data <== replayer.io.data_req.bits.data
}
when (io.cpu.req_val) {
r_cpu_req_idx <== io.cpu.req_idx
r_cpu_req_cmd <== io.cpu.req_cmd
r_cpu_req_type <== io.cpu.req_type
r_cpu_req_tag <== io.cpu.req_tag
when (req_write) {
r_cpu_req_data <== io.cpu.req_data
}
}
// refill counter
val rr_count = Reg(resetVal = UFix(0, log2up(REFILL_CYCLES)))
val rr_count_next = rr_count + UFix(1)
when (io.mem.resp_val) { rr_count <== rr_count_next }
val misaligned =
(((r_cpu_req_type === MT_H) || (r_cpu_req_type === MT_HU)) && (r_cpu_req_idx(0) != Bits(0))) ||
(((r_cpu_req_type === MT_W) || (r_cpu_req_type === MT_WU)) && (r_cpu_req_idx(1,0) != Bits(0))) ||
((r_cpu_req_type === MT_D) && (r_cpu_req_idx(2,0) != Bits(0)));
io.cpu.xcpt_ma_ld := r_cpu_req_val_ && r_req_read && misaligned
io.cpu.xcpt_ma_st := r_cpu_req_val_ && r_req_write && misaligned
// tags
val meta = new MetaDataArrayArray(lines)
val meta_arb = (new Arbiter(3)) { new MetaArrayArrayReq() }
meta_arb.io.out <> meta.io.req
// data
val data = new DataArrayArray(lines)
val data_arb = (new Arbiter(5)) { new DataArrayArrayReq() }
data_arb.io.out <> data.io.req
// cpu tag check
meta_arb.io.in(2).valid := io.cpu.req_val
meta_arb.io.in(2).bits.inner_req.idx := io.cpu.req_idx(indexmsb,indexlsb)
meta_arb.io.in(2).bits.inner_req.rw := Bool(false)
meta_arb.io.in(2).bits.inner_req.data.valid := Bool(false) // don't care
meta_arb.io.in(2).bits.inner_req.data.dirty := Bool(false) // don't care
meta_arb.io.in(2).bits.inner_req.data.tag := UFix(0) // don't care
meta_arb.io.in(2).bits.way_en := ~UFix(0, NWAYS)
val early_tag_nack = !meta_arb.io.in(2).ready
//val tag_match_arr = meta.io.resp.map(r => r.valid && (r.tag === io.cpu_req_ppn))
val tag_match_arr = (0 until NWAYS).map( w => meta.io.resp(w).valid && (meta.io.resp(w).tag === io.cpu.req_ppn))
val tag_match = Cat(Bits(0),tag_match_arr:_*).orR
val tag_hit = r_cpu_req_val && tag_match
val tag_miss = r_cpu_req_val && !tag_match
val hit_way_id = OHToUFix(Cat(Bits(0),tag_match_arr:_*))
val meta_hit_mux = meta.io.resp(hit_way_id)
// writeback unit
val wb = new WritebackUnit
val wb_arb = (new Arbiter(2)) { new WritebackReq() }
wb_arb.io.out <> wb.io.req
wb.io.data_req <> data_arb.io.in(3)
val data_resp_way_id = Mux(data.io.way_en === ~UFix(0, NWAYS), hit_way_id, OHToUFix(data.io.way_en))
val data_resp_mux = data.io.resp(data_resp_way_id)
wb.io.data_resp <> data_resp_mux
// replacement policy
val replacer = new RandomReplacementWayGen()
replacer.io.way_en := tag_miss & ~UFix(0, NWAYS)
val replaced_way_id = replacer.io.way_id
val meta_wb_mux = meta.io.resp(replaced_way_id)
val dirty = meta_wb_mux.valid && meta_wb_mux.dirty //TODO: check all dirty uses
// refill response
val block_during_refill = !io.mem.resp_val && (rr_count != UFix(0))
data_arb.io.in(0).bits.inner_req.offset := rr_count
data_arb.io.in(0).bits.inner_req.rw := !block_during_refill
data_arb.io.in(0).bits.inner_req.wmask := ~UFix(0, MEM_DATA_BITS/8)
data_arb.io.in(0).bits.inner_req.data := io.mem.resp_data
data_arb.io.in(0).valid := io.mem.resp_val || block_during_refill
// load hits
data_arb.io.in(4).bits.inner_req.offset := io.cpu.req_idx(offsetmsb,ramindexlsb)
data_arb.io.in(4).bits.inner_req.idx := io.cpu.req_idx(indexmsb,indexlsb)
data_arb.io.in(4).bits.inner_req.rw := Bool(false)
data_arb.io.in(4).bits.inner_req.wmask := UFix(0) // don't care
data_arb.io.in(4).bits.inner_req.data := io.mem.resp_data // don't care
data_arb.io.in(4).valid := io.cpu.req_val && req_read
data_arb.io.in(4).bits.way_en := ~UFix(0, NWAYS) // intiate load on all ways, mux after tag check
val early_load_nack = req_read && !data_arb.io.in(4).ready
// store hits and AMO hits and misses use a pending store register.
// we nack new stores if a pending store can't retire for some reason.
// we drain a pending store if the CPU performs a store or a
// conflictig load, or if the cache is idle, or after a miss.
val p_store_idx_match = p_store_valid && (r_cpu_req_idx(indexmsb,indexlsb) === p_store_idx(indexmsb,indexlsb))
val p_store_offset_match = (r_cpu_req_idx(indexlsb-1,offsetlsb) === p_store_idx(indexlsb-1,offsetlsb))
val p_store_match = r_cpu_req_val && r_req_read && p_store_idx_match && p_store_offset_match
val drain_store_val = (p_store_valid && (!io.cpu.req_val || !req_read || Reg(tag_miss))) || p_store_match
data_arb.io.in(2).bits.inner_req.offset := p_store_idx(offsetmsb,ramindexlsb)
data_arb.io.in(2).bits.inner_req.idx := p_store_idx(indexmsb,indexlsb)
data_arb.io.in(2).bits.inner_req.rw := Bool(true)
data_arb.io.in(2).valid := drain_store_val
data_arb.io.in(2).bits.way_en := UFixToOH(p_store_way_id.toUFix, NWAYS)
val drain_store = drain_store_val && data_arb.io.in(2).ready
val p_store_rdy = !p_store_valid || drain_store
val p_amo = Reg(tag_hit && r_req_amo && p_store_rdy && !p_store_match || r_replay_amo, resetVal = Bool(false))
p_store_valid <== !p_store_rdy || (tag_hit && r_req_store) || p_amo
// writeback
val wb_rdy = wb_arb.io.in(1).ready && !p_store_idx_match
wb_arb.io.in(1).valid := tag_miss && r_req_readwrite && dirty && !p_store_idx_match
wb_arb.io.in(1).bits.ppn := meta_wb_mux.tag
wb_arb.io.in(1).bits.idx := r_cpu_req_idx(indexmsb,indexlsb)
wb_arb.io.in(1).bits.way_id := replaced_way_id
// tag update after a miss or a store to an exclusive clean line.
val clear_valid = tag_miss && r_req_readwrite && meta_hit_mux.valid && (!dirty || wb_rdy)
val set_dirty = tag_hit && !meta_hit_mux.dirty && r_req_write
meta.io.state_req.bits.inner_req.rw := Bool(true)
meta.io.state_req.bits.inner_req.idx := r_cpu_req_idx(indexmsb,indexlsb)
meta.io.state_req.bits.inner_req.data.valid := tag_match
meta.io.state_req.bits.inner_req.data.dirty := tag_match
meta.io.state_req.valid := clear_valid || set_dirty
meta.io.state_req.bits.way_en := Cat(Bits(0),tag_match_arr:_*)
// pending store data, also used for AMO RHS
val storegen = new StoreDataGen
val amoalu = new AMOALU
storegen.io.typ := r_cpu_req_type
storegen.io.din := r_cpu_req_data
when (p_amo) {
p_store_data <== amoalu.io.out
}
when (tag_hit && r_req_write && p_store_rdy || r_replay_amo) {
p_store_idx <== Mux(r_replay_amo, Reg(Cat(replayer.io.data_req.bits.idx, replayer.io.data_req.bits.offset)), r_cpu_req_idx)
p_store_way_id <== Mux(r_replay_amo, Reg(replayer.io.replay.bits.way_id), hit_way_id)
p_store_type <== Mux(r_replay_amo, Reg(replayer.io.data_req.bits.typ), r_cpu_req_type)
p_store_cmd <== Mux(r_replay_amo, Reg(replayer.io.data_req.bits.cmd), r_cpu_req_cmd)
p_store_data <== storegen.io.dout
}
// miss handling
val mshr = new MSHRFile()
mshr.io.req_val := tag_miss && r_req_readwrite && (!dirty || wb_rdy) && (!r_req_write || replayer.io.sdq_enq.ready)
mshr.io.req_ppn := io.cpu.req_ppn
mshr.io.req_idx := r_cpu_req_idx(indexmsb,indexlsb)
mshr.io.req_tag := r_cpu_req_tag
mshr.io.req_offset := r_cpu_req_idx(offsetmsb,0)
mshr.io.req_cmd := r_cpu_req_cmd
mshr.io.req_type := r_cpu_req_type
mshr.io.req_sdq_id := replayer.io.sdq_id
mshr.io.req_way_id := replaced_way_id
mshr.io.mem_resp_val := io.mem.resp_val && (~rr_count === UFix(0))
mshr.io.mem_resp_tag := io.mem.resp_tag
mshr.io.mem_req <> wb.io.refill_req
mshr.io.meta_req <> meta_arb.io.in(1)
mshr.io.replay <> replayer.io.replay
replayer.io.sdq_enq.valid := tag_miss && r_req_write && (!dirty || wb_rdy) && mshr.io.req_rdy
replayer.io.sdq_enq.bits := storegen.io.dout
data_arb.io.in(0).bits.inner_req.idx := mshr.io.mem_resp_idx
data_arb.io.in(0).bits.way_en := UFixToOH(mshr.io.mem_resp_way_id.toUFix, NWAYS)
// replays
val replay = replayer.io.data_req.bits
val stall_replay = r_replay_amo || p_amo || p_store_valid
val replay_val = replayer.io.data_req.valid && !stall_replay
val replay_rdy = data_arb.io.in(1).ready
data_arb.io.in(1).bits.inner_req.offset := replay.offset(offsetmsb,ramindexlsb)
data_arb.io.in(1).bits.inner_req.idx := replay.idx
data_arb.io.in(1).bits.inner_req.rw := replay.cmd === M_XWR
data_arb.io.in(1).valid := replay_val
data_arb.io.in(1).bits.way_en := UFixToOH(replayer.io.way_id, NWAYS)
replayer.io.data_req.ready := replay_rdy && !stall_replay
r_replay_amo <== replay_amo_val && replay_rdy && !stall_replay
// store write mask generation.
// assumes store replays are higher-priority than pending stores.
val maskgen = new StoreMaskGen
val store_offset = Mux(!replay_val, p_store_idx(offsetmsb,0), replay.offset)
maskgen.io.typ := Mux(!replay_val, p_store_type, replay.typ)
maskgen.io.addr := store_offset(offsetlsb-1,0)
val store_wmask_wide = maskgen.io.wmask << Cat(store_offset(ramindexlsb-1,offsetlsb), Bits(0, log2up(CPU_DATA_BITS/8))).toUFix
val store_data = Mux(!replay_val, p_store_data, replay.data)
val store_data_wide = Fill(MEM_DATA_BITS/CPU_DATA_BITS, store_data)
data_arb.io.in(1).bits.inner_req.data := store_data_wide
data_arb.io.in(1).bits.inner_req.wmask := store_wmask_wide
data_arb.io.in(2).bits.inner_req.data := store_data_wide
data_arb.io.in(2).bits.inner_req.wmask := store_wmask_wide
// load data subword mux/sign extension.
// subword loads are delayed by one cycle.
val loadgen = new LoadDataGen
val loadgen_use_replay = Reg(replay_val && replay_rdy)
loadgen.io.typ := Mux(loadgen_use_replay, Reg(replay.typ), r_cpu_req_type)
loadgen.io.addr := Mux(loadgen_use_replay, Reg(replay.offset), r_cpu_req_idx)(ramindexlsb-1,0)
loadgen.io.din := data_resp_mux
amoalu.io.cmd := p_store_cmd
amoalu.io.typ := p_store_type
amoalu.io.lhs := loadgen.io.r_dout.toUFix
amoalu.io.rhs := p_store_data.toUFix
early_nack <== early_tag_nack || early_load_nack || r_cpu_req_val && r_req_amo || replay_amo_val || r_replay_amo
2011-12-17 12:26:11 +01:00
// reset and flush unit
val flusher = new FlushUnit(lines)
val flushed = Reg(resetVal = Bool(true))
val flush_rdy = mshr.io.fence_rdy && wb_rdy && !p_store_valid
flushed <== flushed && !r_cpu_req_val || r_cpu_req_val && r_req_flush && flush_rdy && flusher.io.req.ready
flusher.io.req.valid := r_cpu_req_val && r_req_flush && flush_rdy && !flushed
2011-12-17 12:26:11 +01:00
flusher.io.wb_req <> wb_arb.io.in(0)
flusher.io.meta_req <> meta_arb.io.in(0)
flusher.io.meta_resp <> meta.io.resp
flusher.io.resp.ready := Bool(true) // we don't respond to flush requests
// we usually nack rather than reporting that the cache is not ready.
// fences and flushes are the exceptions.
val pending_fence = Reg(resetVal = Bool(false))
pending_fence <== (r_cpu_req_val && r_req_fence || pending_fence) && !flush_rdy
val nack_hit = p_store_match || r_req_write && !p_store_rdy
val nack_miss = dirty && !wb_rdy || !mshr.io.req_rdy || r_req_write && !replayer.io.sdq_enq.ready
val nack_flush = !flush_rdy && (r_req_fence || r_req_flush) ||
!flushed && r_req_flush
val nack = early_nack || r_req_readwrite && Mux(tag_match, nack_hit, nack_miss) || nack_flush
io.cpu.req_rdy := flusher.io.req.ready && !(r_cpu_req_val_ && r_req_flush) && !pending_fence
io.cpu.resp_nack := r_cpu_req_val_ && !io.cpu.req_kill && nack
io.cpu.resp_val := (tag_hit && !nack_hit && r_req_read) || replayer.io.cpu_resp_val
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io.cpu.resp_replay := replayer.io.cpu_resp_val
io.cpu.resp_miss := tag_miss && !nack_miss && r_req_read
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io.cpu.resp_tag := Mux(replayer.io.cpu_resp_val, replayer.io.cpu_resp_tag, r_cpu_req_tag)
io.cpu.resp_data := loadgen.io.dout
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io.cpu.resp_data_subword := loadgen.io.r_dout_subword
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wb.io.mem_req.ready := io.mem.req_rdy
io.mem.req_val := wb.io.mem_req.valid
io.mem.req_rw := wb.io.mem_req.bits.rw
io.mem.req_wdata := wb.io.mem_req_data
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io.mem.req_tag := wb.io.mem_req.bits.tag.toUFix
io.mem.req_addr := wb.io.mem_req.bits.addr
}
}