package Top { import Chisel._ import Node._; import Constants._; import scala.math._; // interface between D$ and processor class ioDmem(view: List[String] = null) extends Bundle(view) { val req_val = Bool('input); val req_rdy = Bool('output); val req_cmd = Bits(4, 'input); val req_type = Bits(3, 'input); val req_addr = UFix(32, 'input); val req_data = Bits(64, 'input); val req_tag = Bits(12, 'input); val resp_val = Bool('output); val resp_data = Bits(64, 'output); val resp_tag = Bits(12, 'output); } // interface between D$ and memory class ioDcache(view: List[String] = null) extends Bundle(view) { val req_addr = UFix(32, 'input); val req_tag = UFix(3, 'input); val req_val = Bool('input); val req_rdy = Bool('output); val req_wdata = Bits(128, 'input); val req_rw = Bool('input); val resp_data = Bits(128, 'output); val resp_tag = Bits(3, 'output); val resp_val = Bool('output); } class ioDCacheDM extends Bundle() { val cpu = new ioDmem(); val mem = new ioDcache().flip(); } // state machine to flush (write back dirty lines, invalidate clean ones) the D$ class rocketDCacheDM_flush(lines: Int, addrbits: Int) extends Component { val io = new ioDCacheDM(); // val dcache = new rocketDCacheDM(lines, addrbits); val dcache = new rocketDCacheDM_1C(lines, addrbits); val indexbits = ceil(log10(lines)/log10(2)).toInt; val offsetbits = 6; val tagmsb = addrbits - 1; val taglsb = indexbits+offsetbits; val indexmsb = taglsb-1; val indexlsb = offsetbits; val offsetmsb = indexlsb-1; val offsetlsb = 3; val flush_count = Reg(resetVal = UFix(0, indexbits)); val flush_resp_count = Reg(resetVal = UFix(0, indexbits)); val flushing = Reg(resetVal = Bool(false)); val flush_waiting = Reg(resetVal = Bool(false)); val r_cpu_req_tag = Reg(resetVal = Bits(0, 12)); when (io.cpu.req_val && io.cpu.req_rdy && (io.cpu.req_cmd === M_FLA)) { r_cpu_req_tag <== io.cpu.req_tag; flushing <== Bool(true); flush_waiting <== Bool(true); } when (dcache.io.cpu.req_rdy && (flush_count === ~Bits(0, indexbits))) { flushing <== Bool(false); } when (dcache.io.cpu.resp_val && (dcache.io.cpu.resp_tag === r_cpu_req_tag) && (flush_resp_count === ~Bits(0, indexbits))) { flush_waiting <== Bool(false); } when (flushing && dcache.io.cpu.req_rdy) { flush_count <== flush_count + UFix(1,1); } when (flush_waiting && dcache.io.cpu.resp_val && (dcache.io.cpu.resp_tag === r_cpu_req_tag)) { flush_resp_count <== flush_resp_count + UFix(1,1); } dcache.io.cpu.req_val := (io.cpu.req_val && (io.cpu.req_cmd != M_FLA) && !flush_waiting) || flushing; dcache.io.cpu.req_cmd := Mux(flushing, M_FLA, io.cpu.req_cmd); dcache.io.cpu.req_addr := Mux(flushing, Cat(Bits(0,tagmsb-taglsb+1), flush_count, Bits(0,offsetbits)).toUFix, io.cpu.req_addr); dcache.io.cpu.req_tag := Mux(flushing, r_cpu_req_tag, io.cpu.req_tag); dcache.io.cpu.req_type := io.cpu.req_type; dcache.io.cpu.req_data ^^ io.cpu.req_data; dcache.io.mem ^^ io.mem; io.cpu.req_rdy := dcache.io.cpu.req_rdy && !flush_waiting; io.cpu.resp_data := dcache.io.cpu.resp_data; io.cpu.resp_tag := dcache.io.cpu.resp_tag; io.cpu.resp_val := dcache.io.cpu.resp_val & !(flush_waiting && (io.cpu.resp_tag === r_cpu_req_tag) && (flush_count != ~Bits(0, addrbits))); } class rocketDCacheDM_1C(lines: Int, addrbits: Int) extends Component { val io = new ioDCacheDM(); val indexbits = ceil(log10(lines)/log10(2)).toInt; val offsetbits = 6; val tagmsb = addrbits - 1; val taglsb = indexbits+offsetbits; val indexmsb = taglsb-1; val indexlsb = offsetbits; val offsetmsb = indexlsb-1; val offsetlsb = 3; val s_reset :: s_ready :: s_replay_load :: s_start_writeback :: s_writeback :: s_req_refill :: s_refill :: s_resolve_miss :: Nil = Enum(8) { UFix() }; val state = Reg(resetVal = s_reset); val r_cpu_req_addr = Reg(resetVal = Bits(0, addrbits)); val r_cpu_req_val = Reg(resetVal = Bool(false)); val r_cpu_req_data = Reg(resetVal = Bits(0,64)); val r_cpu_req_cmd = Reg(resetVal = Bits(0,4)); val r_cpu_req_type = Reg(resetVal = Bits(0,3)); val r_cpu_req_tag = Reg(resetVal = Bits(0,5)); val p_store_data = Reg(resetVal = Bits(0,64)); val p_store_addr = Reg(resetVal = Bits(0,64)); val p_store_wmask = Reg(resetVal = Bits(0,64)); val p_store_valid = Reg(resetVal = Bool(false)); val req_load = (r_cpu_req_cmd === M_XRD); val req_store = (r_cpu_req_cmd === M_XWR); val req_flush = (r_cpu_req_cmd === M_FLA); when (io.cpu.req_val && io.cpu.req_rdy) { r_cpu_req_addr <== io.cpu.req_addr; r_cpu_req_data <== io.cpu.req_data; 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 (io.cpu.req_rdy) { r_cpu_req_val <== io.cpu.req_val; } when ((state === s_resolve_miss) && !req_load) { r_cpu_req_val <== Bool(false); } // counter val rr_count = Reg(resetVal = UFix(0,2)); val rr_count_next = rr_count + UFix(1); when (((state === s_refill) && io.mem.resp_val) || ((state === s_writeback) && io.mem.req_rdy)) { rr_count <== rr_count_next; } // tag array val tag_we = (state === s_refill) && io.mem.req_rdy && (rr_count === UFix(3,2)); val tag_waddr = r_cpu_req_addr(indexmsb, indexlsb).toUFix; val tag_wdata = r_cpu_req_addr(tagmsb, taglsb); val tag_array = Mem(lines, tag_we, tag_waddr, tag_wdata); val tag_raddr = Mux((state === s_ready), io.cpu.req_addr(indexmsb, indexlsb).toUFix, r_cpu_req_addr(indexmsb, indexlsb).toUFix); val tag_rdata = Reg(tag_array.read(tag_raddr)); // valid bit array val vb_array = Reg(resetVal = Bits(0, lines)); val vb_rdata = Reg(vb_array(tag_raddr)); when (tag_we && !req_flush) { vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(1,1)); } when (tag_we && req_flush) { vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1)); } val tag_valid = vb_rdata.toBool; val tag_match = tag_valid && (tag_rdata === r_cpu_req_addr(tagmsb, taglsb)); // generate write mask and store data signals based on store type and address LSBs val wmask_b = Mux(r_cpu_req_addr(2,0) === UFix(0, 3), Bits("b0000_0001", 8), Mux(r_cpu_req_addr(2,0) === UFix(1, 3), Bits("b0000_0010", 8), Mux(r_cpu_req_addr(2,0) === UFix(2, 3), Bits("b0000_0100", 8), Mux(r_cpu_req_addr(2,0) === UFix(3, 3), Bits("b0000_1000", 8), Mux(r_cpu_req_addr(2,0) === UFix(4, 3), Bits("b0001_0000", 8), Mux(r_cpu_req_addr(2,0) === UFix(5, 3), Bits("b0010_0000", 8), Mux(r_cpu_req_addr(2,0) === UFix(6, 3), Bits("b0100_0000", 8), Mux(r_cpu_req_addr(2,0) === UFix(7, 3), Bits("b1000_0000", 8), UFix(0, 8))))))))); val wmask_h = Mux(r_cpu_req_addr(2,1) === UFix(0, 2), Bits("b0000_0011", 8), Mux(r_cpu_req_addr(2,1) === UFix(1, 2), Bits("b0000_1100", 8), Mux(r_cpu_req_addr(2,1) === UFix(2, 2), Bits("b0011_0000", 8), Mux(r_cpu_req_addr(2,1) === UFix(3, 2), Bits("b1100_0000", 8), UFix(0, 8))))); val wmask_w = Mux(r_cpu_req_addr(2) === UFix(0, 1), Bits("b0000_1111", 8), Mux(r_cpu_req_addr(2) === UFix(1, 1), Bits("b1111_0000", 8), UFix(0, 8))); val wmask_d = Bits("b1111_1111", 8); val store_wmask = Mux(r_cpu_req_type === MT_B, wmask_b, Mux(r_cpu_req_type === MT_H, wmask_h, Mux(r_cpu_req_type === MT_W, wmask_w, Mux(r_cpu_req_type === MT_D, wmask_d, UFix(0, 8))))); val store_data = Mux(r_cpu_req_type === MT_B, Fill(8, r_cpu_req_data( 7,0)), Mux(r_cpu_req_type === MT_H, Fill(4, r_cpu_req_data(15,0)), Mux(r_cpu_req_type === MT_W, Fill(2, r_cpu_req_data(31,0)), Mux(r_cpu_req_type === MT_D, r_cpu_req_data, UFix(0, 64))))); when ((state === s_ready) && r_cpu_req_val && req_store) { p_store_data <== store_data; p_store_addr <== r_cpu_req_addr; p_store_wmask <== store_wmask; p_store_valid <== Bool(true); } val addr_match = (r_cpu_req_addr(tagmsb, offsetlsb) === p_store_addr(tagmsb, offsetlsb)); val drain_store = ((state === s_ready) && p_store_valid && (!r_cpu_req_val || !tag_match || !req_load || addr_match)) val resolve_store = (state === s_resolve_miss) && req_store; val do_store = drain_store | resolve_store; // dirty bit array val db_array = Reg(resetVal = Bits(0, lines)); val db_rdata = Reg(db_array(tag_raddr)); val tag_dirty = db_rdata.toBool; when (do_store) { p_store_valid <== Bool(false); db_array <== db_array.bitSet(p_store_addr(indexmsb, indexlsb).toUFix, UFix(1,1)); } when (tag_we) { db_array <== db_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1)); } // data array val data_array_we = ((state === s_refill) && io.mem.resp_val) || do_store; val data_array_waddr = Mux((state === s_refill), Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix, p_store_addr(indexmsb, offsetmsb-1).toUFix); val data_array_wdata = Mux((state === s_refill), io.mem.resp_data, Cat(p_store_data, p_store_data)); val p_wmask_expand = Cat(Fill(8, p_store_wmask(7)), Fill(8, p_store_wmask(6)), Fill(8, p_store_wmask(5)), Fill(8, p_store_wmask(4)), Fill(8, p_store_wmask(3)), Fill(8, p_store_wmask(2)), Fill(8, p_store_wmask(1)), Fill(8, p_store_wmask(0))); val da_store_wmask = Mux(p_store_addr(offsetlsb).toBool, Cat(p_wmask_expand, Bits(0,64)), Cat(Bits(0,64), p_wmask_expand)); val data_array_wmask = Mux((state === s_refill), ~Bits(0,128), da_store_wmask); val data_array = Mem(lines*4, data_array_we, data_array_waddr, data_array_wdata, wrMask = data_array_wmask, resetVal = null); val data_array_raddr = Mux((state === s_writeback) && io.mem.req_rdy, Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count_next).toUFix, Mux((state === s_start_writeback) || (state === s_writeback), Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix, Mux((state === s_resolve_miss) || (state === s_replay_load), r_cpu_req_addr(indexmsb, offsetmsb-1), io.cpu.req_addr(indexmsb, offsetmsb-1)))); val data_array_rdata = Reg(data_array.read(data_array_raddr)); val ldst_conflict = r_cpu_req_val && req_load && p_store_valid && addr_match; // output signals io.cpu.req_rdy := (state === s_ready) && !ldst_conflict && (!r_cpu_req_val || (tag_match && !req_flush)); io.cpu.resp_val := ((state === s_ready) && r_cpu_req_val && tag_match && req_load && !(p_store_valid && addr_match)) || ((state === s_resolve_miss) && req_flush); io.cpu.resp_tag := Cat(Bits(0,1), r_cpu_req_type, r_cpu_req_addr(2,0), r_cpu_req_tag); io.cpu.resp_data := Mux(r_cpu_req_addr(offsetlsb).toBool, data_array_rdata(127, 64), data_array_rdata(63,0)); io.mem.req_val := (state === s_req_refill) || (state === s_writeback); io.mem.req_rw := (state === s_writeback); io.mem.req_wdata := data_array_rdata; io.mem.req_tag := UFix(0); io.mem.req_addr := Mux(state === s_writeback, Cat(tag_rdata, r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix, Cat(r_cpu_req_addr(tagmsb, indexlsb), Bits(0,2)).toUFix); // control state machine switch (state) { is (s_reset) { state <== s_ready; } is (s_ready) { when (ldst_conflict) { state <== s_replay_load; } when (!r_cpu_req_val || tag_match) { state <== s_ready; } when (tag_valid & tag_dirty) { state <== s_start_writeback; } when (req_flush) { state <== s_resolve_miss; } otherwise { state <== s_req_refill; } } is (s_replay_load) { state <== s_ready; } is (s_start_writeback) { state <== s_writeback; } is (s_writeback) { when (io.mem.req_rdy && (rr_count === UFix(3,2))) { when (req_flush) { state <== s_resolve_miss; } otherwise { state <== s_req_refill; } } } is (s_req_refill) { when (io.mem.req_rdy) { state <== s_refill; } } is (s_refill) { when (io.mem.resp_val && (rr_count === UFix(3,2))) { state <== s_resolve_miss; } } is (s_resolve_miss) { state <== s_ready; } } } // basic direct mapped data cache, 2 cycle read latency // parameters : // lines = # of cache lines // addr_bits = address width (word addressable) bits // 64 bit wide cpu port, 128 bit wide memory port, 64 byte cachelines /* class rocketDCacheDM(lines: Int, addrbits: Int) extends Component { val io = new ioDCacheDM(); val indexbits = ceil(log10(lines)/log10(2)).toInt; val offsetbits = 6; val tagmsb = addrbits - 1; val taglsb = indexbits+offsetbits; val indexmsb = taglsb-1; val indexlsb = offsetbits; val offsetmsb = indexlsb-1; val offsetlsb = 3; val s_reset :: s_ready :: s_start_writeback :: s_writeback :: s_req_refill :: s_refill :: s_resolve_miss :: Nil = Enum(7) { UFix() }; val state = Reg(resetVal = s_reset); val r_cpu_req_addr = Reg(Bits(0, addrbits)); val r_r_cpu_req_addr = Reg(r_cpu_req_addr); val r_cpu_req_val = Reg(Bool(false)); val r_cpu_req_data = Reg(Bits(0,64)); val r_cpu_req_cmd = Reg(Bits(0,4)); val r_cpu_req_wmask = Reg(Bits(0,8)); val r_cpu_req_tag = Reg(Bits(0,12)); val r_cpu_resp_tag = Reg(r_cpu_req_tag); val r_cpu_resp_val = Reg(Bool(false)); when (io.cpu.req_val && io.cpu.req_rdy) { r_cpu_req_addr <== io.cpu.req_addr; r_cpu_req_data <== io.cpu.req_data; r_cpu_req_cmd <== io.cpu.req_cmd; r_cpu_req_wmask <== io.cpu.req_wmask; r_cpu_req_tag <== io.cpu.req_tag; } val req_load = (r_cpu_req_cmd === M_XRD); val req_store = (r_cpu_req_cmd === M_XWR); val req_flush = (r_cpu_req_cmd === M_FLA); when (io.cpu.req_rdy) { r_cpu_req_val <== io.cpu.req_val; } otherwise { r_cpu_req_val <== Bool(false); } // counter val rr_count = Reg(resetVal = UFix(0,2)); val rr_count_next = rr_count + UFix(1); when (((state === s_refill) && io.mem.resp_val) || ((state === s_writeback) && io.mem.req_rdy)) { rr_count <== rr_count_next; } // tag array val tag_we = (state === s_resolve_miss); val tag_waddr = r_cpu_req_addr(indexmsb, indexlsb).toUFix; val tag_wdata = r_cpu_req_addr(tagmsb, taglsb); val tag_array = Mem(lines, tag_we, tag_waddr, tag_wdata); val tag_raddr = Mux((state === s_ready), io.cpu.req_addr(indexmsb, indexlsb).toUFix, r_cpu_req_addr(indexmsb, indexlsb).toUFix); val tag_rdata = Reg(tag_array.read(tag_raddr)); // valid bit array val vb_array = Reg(resetVal = Bits(0, lines)); val vb_rdata = Reg(vb_array(tag_raddr)); when (tag_we && !req_flush) { vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(1,1)); } when (tag_we && req_flush) { vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1)); } val tag_valid = vb_rdata.toBool; val tag_match = tag_valid && !req_flush && (tag_rdata === r_cpu_req_addr(tagmsb, taglsb)); val store = ((state === s_ready) && r_cpu_req_val && req_store && tag_match ) || ((state === s_resolve_miss) && req_store); // dirty bit array val db_array = Reg(resetVal = Bits(0, lines)); val db_rdata = Reg(db_array(tag_raddr)); val tag_dirty = db_rdata.toBool; when (store) { db_array <== db_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(1,1)); } when (tag_we) { db_array <== db_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1)); } // data array val data_array_we = ((state === s_refill) && io.mem.resp_val) || store; val data_array_waddr = Mux((state === s_refill), Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix, r_cpu_req_addr(indexmsb, offsetmsb-1).toUFix); val data_array_wdata = Mux((state === s_refill), io.mem.resp_data, Cat(r_cpu_req_data, r_cpu_req_data)); val req_wmask_expand = Cat(Fill(8, r_cpu_req_wmask(7)), Fill(8, r_cpu_req_wmask(6)), Fill(8, r_cpu_req_wmask(5)), Fill(8, r_cpu_req_wmask(4)), Fill(8, r_cpu_req_wmask(3)), Fill(8, r_cpu_req_wmask(2)), Fill(8, r_cpu_req_wmask(1)), Fill(8, r_cpu_req_wmask(0))); val store_wmask = Mux(r_cpu_req_addr(offsetlsb).toBool, Cat(req_wmask_expand, Bits(0,64)), Cat(Bits(0,64), req_wmask_expand)); val data_array_wmask = Mux((state === s_refill), ~Bits(0,128), store_wmask); val data_array = Mem(lines*4, data_array_we, data_array_waddr, data_array_wdata, wrMask = data_array_wmask, resetVal = null); val data_array_raddr = Mux((state === s_writeback) && io.mem.req_rdy, Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count_next).toUFix, Mux((state === s_start_writeback) || (state === s_writeback), Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix, r_cpu_req_addr(indexmsb, offsetmsb-1))); val data_array_rdata = Reg(data_array.read(data_array_raddr)); // output signals io.cpu.req_rdy := (state === s_ready) && (!r_cpu_req_val || tag_match); when ((((state === s_ready) && r_cpu_req_val && tag_match) || (state === s_resolve_miss)) && !req_store) { r_cpu_resp_val <== Bool(true); } otherwise { r_cpu_resp_val <== Bool(false); } io.cpu.resp_val := r_cpu_resp_val; io.cpu.resp_data := Mux(r_r_cpu_req_addr(offsetlsb).toBool, data_array_rdata(127, 64), data_array_rdata(63,0)); io.cpu.resp_tag := r_cpu_resp_tag; io.mem.req_val := (state === s_req_refill) || (state === s_writeback); io.mem.req_rw := (state === s_writeback); io.mem.req_wdata := data_array_rdata; io.mem.req_tag := UFix(0); io.mem.req_addr := Mux(state === s_writeback, Cat(tag_rdata, r_cpu_req_addr(indexmsb, indexlsb), rr_count).toUFix, Cat(r_cpu_req_addr(tagmsb, indexlsb), Bits(0,2)).toUFix); // control state machine switch (state) { is (s_reset) { state <== s_ready; } is (s_ready) { when (~r_cpu_req_val) { state <== s_ready; } when (r_cpu_req_val & tag_match) { state <== s_ready; } when (tag_valid & tag_dirty) { state <== s_start_writeback; } when (req_flush) { state <== s_resolve_miss; } otherwise { state <== s_req_refill; } } is (s_start_writeback) { state <== s_writeback; } is (s_writeback) { when (io.mem.req_rdy && (rr_count === UFix(3,2))) { when (req_flush) { state <== s_resolve_miss; } otherwise { state <== s_req_refill; } } } is (s_req_refill) { when (io.mem.req_rdy) { state <== s_refill; } } is (s_refill) { when (io.mem.resp_val && (rr_count === UFix(3,2))) { state <== s_resolve_miss; } } is (s_resolve_miss) { state <== s_ready; } } } */ }