dcache/dtlb overhaul
This commit is contained in:
parent
e4fa94aa27
commit
a1ce908541
@ -76,7 +76,7 @@ class rocketProc extends Component
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dtlb.io.cpu.req_val := ctrl.io.dmem.req_val;
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dtlb.io.cpu.req_cmd := ctrl.io.dmem.req_cmd;
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dtlb.io.cpu.req_asid := Bits(0,ASID_BITS); // FIXME: connect to PCR
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dtlb.io.cpu.req_addr := dpath.io.dmem.req_addr;
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dtlb.io.cpu.req_vpn := dpath.io.dmem.req_addr(VADDR_BITS-1,PGIDX_BITS);
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ctrl.io.xcpt_dtlb_ld := dtlb.io.cpu.xcpt_ld;
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ctrl.io.xcpt_dtlb_st := dtlb.io.cpu.xcpt_st;
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ctrl.io.dtlb_miss := dtlb.io.cpu.resp_miss;
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@ -90,10 +90,13 @@ class rocketProc extends Component
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arb.io.mem ^^ io.dmem
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// connect arbiter to ctrl+dpath+DTLB
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arb.io.cpu.req_val := dtlb.io.cpu.resp_val;
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// arb.io.cpu.req_val := dtlb.io.cpu.resp_val;
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arb.io.cpu.req_val := ctrl.io.dmem.req_val;
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arb.io.cpu.req_cmd := ctrl.io.dmem.req_cmd;
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arb.io.cpu.req_type := ctrl.io.dmem.req_type;
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arb.io.cpu.req_addr := dtlb.io.cpu.resp_addr;
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// arb.io.cpu.req_addr := dtlb.io.cpu.resp_addr;
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arb.io.cpu.req_idx := dpath.io.dmem.req_addr(PGIDX_BITS-1,0);
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arb.io.cpu.req_ppn := dtlb.io.cpu.resp_ppn;
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arb.io.cpu.req_data := dpath.io.dmem.req_data;
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arb.io.cpu.req_tag := dpath.io.dmem.req_tag;
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ctrl.io.dmem.req_rdy := dtlb.io.cpu.req_rdy && arb.io.cpu.req_rdy;
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@ -326,7 +326,8 @@ class rocketCtrl extends Component
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val jr_taken = (ex_reg_br_type === BR_JR);
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val j_taken = (ex_reg_br_type === BR_J);
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io.dmem.req_val := ex_reg_mem_val; // && ~io.dpath.killx;
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// io.dmem.req_val := ex_reg_mem_val;
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io.dmem.req_val := ex_reg_mem_val && ~io.dpath.killx;
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io.dmem.req_cmd := ex_reg_mem_cmd;
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io.dmem.req_type := ex_reg_mem_type;
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@ -5,13 +5,15 @@ import Node._;
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import Constants._;
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import scala.math._;
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// interface between D$ and processor pipeline
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// interface between D$ and processor/DTLB
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class ioDmem(view: List[String] = null) extends Bundle(view) {
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val req_val = Bool('input);
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val req_rdy = Bool('output);
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val req_cmd = Bits(4, 'input);
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val req_type = Bits(3, 'input);
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val req_addr = UFix(PADDR_BITS, 'input);
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val req_idx = Bits(PGIDX_BITS, 'input);
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val req_ppn = Bits(PPN_BITS, 'input);
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// val req_addr = UFix(PADDR_BITS, 'input);
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val req_data = Bits(64, 'input);
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val req_tag = Bits(5, 'input);
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val resp_miss = Bool('output);
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@ -38,6 +40,70 @@ class ioDCacheDM extends Bundle() {
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val mem = new ioDcache().flip();
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}
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class rocketDCacheStoreGen extends Component {
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val io = new Bundle {
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val req_type = Bits(3, 'input);
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val req_addr_lsb = Bits(3, 'input);
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val req_data = Bits(64, 'input);
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val store_wmask = Bits(64, 'output);
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val store_data = Bits(64, 'output);
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}
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// generate write mask and store data signals based on store type and address LSBs
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val wmask_b =
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Mux(io.req_addr_lsb === UFix(0, 3), Bits("b0000_0001", 8),
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Mux(io.req_addr_lsb === UFix(1, 3), Bits("b0000_0010", 8),
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Mux(io.req_addr_lsb === UFix(2, 3), Bits("b0000_0100", 8),
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Mux(io.req_addr_lsb === UFix(3, 3), Bits("b0000_1000", 8),
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Mux(io.req_addr_lsb === UFix(4, 3), Bits("b0001_0000", 8),
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Mux(io.req_addr_lsb === UFix(5, 3), Bits("b0010_0000", 8),
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Mux(io.req_addr_lsb === UFix(6, 3), Bits("b0100_0000", 8),
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Mux(io.req_addr_lsb === UFix(7, 3), Bits("b1000_0000", 8),
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UFix(0, 8)))))))));
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val wmask_h =
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Mux(io.req_addr_lsb(2,1) === UFix(0, 2), Bits("b0000_0011", 8),
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Mux(io.req_addr_lsb(2,1) === UFix(1, 2), Bits("b0000_1100", 8),
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Mux(io.req_addr_lsb(2,1) === UFix(2, 2), Bits("b0011_0000", 8),
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Mux(io.req_addr_lsb(2,1) === UFix(3, 2), Bits("b1100_0000", 8),
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UFix(0, 8)))));
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val wmask_w =
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Mux(io.req_addr_lsb(2) === UFix(0, 1), Bits("b0000_1111", 8),
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Mux(io.req_addr_lsb(2) === UFix(1, 1), Bits("b1111_0000", 8),
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UFix(0, 8)));
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val wmask_d =
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Bits("b1111_1111", 8);
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val store_wmask_byte =
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Mux(io.req_type === MT_B, wmask_b,
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Mux(io.req_type === MT_H, wmask_h,
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Mux(io.req_type === MT_W, wmask_w,
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Mux(io.req_type === MT_D, wmask_d,
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UFix(0, 8)))));
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io.store_wmask :=
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Cat(Fill(8, store_wmask_byte(7)),
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Fill(8, store_wmask_byte(6)),
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Fill(8, store_wmask_byte(5)),
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Fill(8, store_wmask_byte(4)),
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Fill(8, store_wmask_byte(3)),
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Fill(8, store_wmask_byte(2)),
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Fill(8, store_wmask_byte(1)),
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Fill(8, store_wmask_byte(0)));
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io.store_data :=
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Mux(io.req_type === MT_B, Fill(8, io.req_data( 7,0)),
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Mux(io.req_type === MT_H, Fill(4, io.req_data(15,0)),
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Mux(io.req_type === MT_W, Fill(2, io.req_data(31,0)),
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Mux(io.req_type === MT_D, io.req_data,
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UFix(0, 64)))));
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}
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// state machine to flush (write back dirty lines, invalidate clean ones) the D$
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class rocketDCacheDM_flush(lines: Int) extends Component {
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val io = new ioDCacheDM();
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@ -48,6 +114,7 @@ class rocketDCacheDM_flush(lines: Int) extends Component {
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val offsetbits = 6;
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val tagmsb = addrbits - 1;
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val taglsb = indexbits+offsetbits;
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val tagbits = tagmsb-taglsb+1;
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val indexmsb = taglsb-1;
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val indexlsb = offsetbits;
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val offsetmsb = indexlsb-1;
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@ -82,7 +149,11 @@ class rocketDCacheDM_flush(lines: Int) extends Component {
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dcache.io.cpu.req_val := (io.cpu.req_val && (io.cpu.req_cmd != M_FLA) && !flush_waiting) || flushing;
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dcache.io.cpu.req_cmd := Mux(flushing, M_FLA, io.cpu.req_cmd);
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dcache.io.cpu.req_addr := Mux(flushing, Cat(Bits(0,tagmsb-taglsb+1), flush_count, Bits(0,offsetbits)).toUFix, io.cpu.req_addr);
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dcache.io.cpu.req_idx := Mux(flushing, Cat(flush_count, Bits(0,offsetbits)), io.cpu.req_idx);
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dcache.io.cpu.req_ppn := Mux(flushing, UFix(0,PPN_BITS), io.cpu.req_ppn);
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// dcache.io.cpu.req_addr :=
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// Mux(flushing, Cat(Bits(0,tagmsb-taglsb+1), flush_count, Bits(0,offsetbits)).toUFix,
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// io.cpu.req_addr);
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dcache.io.cpu.req_tag := Mux(flushing, r_cpu_req_tag, io.cpu.req_tag);
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dcache.io.cpu.req_type := io.cpu.req_type;
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dcache.io.cpu.req_data ^^ io.cpu.req_data;
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@ -102,9 +173,10 @@ class rocketDCacheDM(lines: Int) extends Component {
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val addrbits = PADDR_BITS;
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val indexbits = ceil(log10(lines)/log10(2)).toInt;
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val offsetbits = 6;
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val tagmsb = addrbits - 1;
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val offsetbits = 6; // 64 byte cache lines = 2^6 bytes
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val tagmsb = PADDR_BITS-1;
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val taglsb = indexbits+offsetbits;
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val tagbits = tagmsb-taglsb+1;
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val indexmsb = taglsb-1;
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val indexlsb = offsetbits;
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val offsetmsb = indexlsb-1;
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@ -113,45 +185,48 @@ class rocketDCacheDM(lines: Int) extends Component {
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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() };
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val state = Reg(resetVal = s_reset);
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val r_cpu_req_addr = Reg(resetVal = Bits(0, addrbits));
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// idx arrives one clock cycle prior to ppn b/c of DTLB
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val r_cpu_req_idx = Reg(resetVal = Bits(0, PGIDX_BITS));
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val r_cpu_req_ppn = Reg(resetVal = Bits(0, PPN_BITS));
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val r_cpu_req_val = Reg(resetVal = Bool(false));
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val r_cpu_req_cmd = Reg(resetVal = Bits(0,4));
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val r_cpu_req_type = Reg(resetVal = Bits(0,3));
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val r_cpu_req_tag = Reg(resetVal = Bits(0,5));
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val r_cpu_resp_val = Reg(resetVal = Bool(false));
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val p_store_data = Reg(resetVal = Bits(0,64));
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val p_store_addr = Reg(resetVal = Bits(0,64));
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val p_store_cmd = Reg(resetVal = Bits(0,4));
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val p_store_type = Reg(resetVal = Bits(0,3));
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val p_store_valid = Reg(resetVal = Bool(false));
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val p_store_data = Reg(resetVal = Bits(0,64));
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val p_store_idx = Reg(resetVal = Bits(0,PGIDX_BITS));
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val p_store_type = Reg(resetVal = Bits(0,3));
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val p_store_valid = Reg(resetVal = Bool(false));
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val req_load = (r_cpu_req_cmd === M_XRD) || (r_cpu_req_cmd === M_PRD);
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val req_store = (r_cpu_req_cmd === M_XWR);
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val req_flush = (r_cpu_req_cmd === M_FLA);
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val req_ptw_load = (r_cpu_req_cmd === M_PRD);
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val req_store = (io.cpu.req_cmd === M_XWR);
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val r_req_load = (r_cpu_req_cmd === M_XRD) || (r_cpu_req_cmd === M_PRD);
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val r_req_store = (r_cpu_req_cmd === M_XWR);
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val r_req_flush = (r_cpu_req_cmd === M_FLA);
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val r_req_ptw_load = (r_cpu_req_cmd === M_PRD);
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when (io.cpu.req_val && io.cpu.req_rdy) {
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r_cpu_req_addr <== io.cpu.req_addr;
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when (io.cpu.req_val && io.cpu.req_rdy) {
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r_cpu_req_idx <== io.cpu.req_idx;
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r_cpu_req_cmd <== io.cpu.req_cmd;
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r_cpu_req_type <== io.cpu.req_type;
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r_cpu_req_tag <== io.cpu.req_tag;
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}
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when (io.cpu.req_val && io.cpu.req_rdy && (io.cpu.req_cmd === M_XWR)) {
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p_store_data <== io.cpu.req_data;
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p_store_addr <== io.cpu.req_addr;
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p_store_type <== io.cpu.req_type;
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p_store_valid <== Bool(true);
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when (state === s_ready) {
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r_cpu_req_ppn <== io.cpu.req_ppn;
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}
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when (io.cpu.req_rdy) {
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r_cpu_req_val <== io.cpu.req_val;
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}
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when ((state === s_resolve_miss) && !req_load) {
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when (state === s_resolve_miss) {
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r_cpu_req_val <== Bool(false);
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when (r_req_load) {
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r_cpu_resp_val <== Bool(true);
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}
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}
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r_cpu_resp_val <== Bool(false);
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// counter
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// refill counter
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val rr_count = Reg(resetVal = UFix(0,2));
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val rr_count_next = rr_count + UFix(1);
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when (((state === s_refill) && io.mem.resp_val) || ((state === s_writeback) && io.mem.req_rdy)) {
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@ -159,146 +234,115 @@ class rocketDCacheDM(lines: Int) extends Component {
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}
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// tag array
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val tagbits = addrbits-(indexbits+offsetbits);
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val tag_addr =
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Mux((state === s_ready), io.cpu.req_idx(PGIDX_BITS-1,offsetbits),
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r_cpu_req_idx(PGIDX_BITS-1,offsetbits)).toUFix;
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val tag_we =
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((state === s_refill) && io.mem.req_rdy && (rr_count === UFix(3,2))) ||
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((state === s_resolve_miss) && req_flush);
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val tag_array = new rocketSRAMsp(lines, tagbits);
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val tag_raddr =
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Mux((state === s_ready), io.cpu.req_addr(indexmsb, indexlsb).toUFix,
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r_cpu_req_addr(indexmsb, indexlsb).toUFix);
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tag_array.io.a := tag_raddr;
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tag_array.io.d := r_cpu_req_addr(tagmsb, taglsb);
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((state === s_resolve_miss) && r_req_flush);
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val tag_array = new rocketSRAMsp(lines, tagbits);
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tag_array.io.a := tag_addr;
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tag_array.io.d := r_cpu_req_ppn;
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tag_array.io.we := tag_we;
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tag_array.io.bweb := ~Bits(0,tagbits);
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tag_array.io.ce := Bool(true); // FIXME
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val tag_rdata = tag_array.io.q;
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val tag_rdata = tag_array.io.q;
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// valid bit array
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val vb_array = Reg(resetVal = Bits(0, lines));
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val vb_rdata = Reg(vb_array(tag_raddr));
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when (tag_we && !req_flush) {
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vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(1,1));
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// val vb_rdata = Reg(vb_array(tag_raddr));
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when (tag_we && !r_req_flush) {
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vb_array <== vb_array.bitSet(r_cpu_req_idx(PGIDX_BITS-1,offsetbits).toUFix, UFix(1,1));
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}
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when (tag_we && req_flush) {
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vb_array <== vb_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1));
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when (tag_we && r_req_flush) {
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vb_array <== vb_array.bitSet(r_cpu_req_idx(PGIDX_BITS-1,offsetbits).toUFix, UFix(0,1));
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}
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val tag_valid = vb_rdata.toBool;
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val tag_match = tag_valid && (tag_rdata === r_cpu_req_addr(tagmsb, taglsb));
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val tag_valid = Reg(vb_array(tag_addr)).toBool;
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val tag_match = (tag_rdata === io.cpu.req_ppn);
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val addr_match = (r_cpu_req_idx(PGIDX_BITS-1,offsetbits) === p_store_idx(PGIDX_BITS-1,offsetbits));
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val ldst_conflict = r_cpu_req_val && r_req_load && p_store_valid && addr_match;
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// write the pending store data when the cache is idle, when the next command isn't a load
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// or when there's a load to the same address (in which case there's a 2 cycle delay:
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// once cycle to write the store data and another to read the data back)
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val drain_store = p_store_valid && (!io.cpu.req_val || req_store || ldst_conflict);
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// write pending store data from a store which missed
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// after the cache line refill has completed
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val resolve_store = (state === s_resolve_miss) && r_req_store;
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// generate write mask and store data signals based on store type and address LSBs
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val wmask_b =
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Mux(p_store_addr(2,0) === UFix(0, 3), Bits("b0000_0001", 8),
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Mux(p_store_addr(2,0) === UFix(1, 3), Bits("b0000_0010", 8),
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Mux(p_store_addr(2,0) === UFix(2, 3), Bits("b0000_0100", 8),
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Mux(p_store_addr(2,0) === UFix(3, 3), Bits("b0000_1000", 8),
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Mux(p_store_addr(2,0) === UFix(4, 3), Bits("b0001_0000", 8),
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Mux(p_store_addr(2,0) === UFix(5, 3), Bits("b0010_0000", 8),
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Mux(p_store_addr(2,0) === UFix(6, 3), Bits("b0100_0000", 8),
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Mux(p_store_addr(2,0) === UFix(7, 3), Bits("b1000_0000", 8),
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UFix(0, 8)))))))));
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val wmask_h =
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Mux(p_store_addr(2,1) === UFix(0, 2), Bits("b0000_0011", 8),
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Mux(p_store_addr(2,1) === UFix(1, 2), Bits("b0000_1100", 8),
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Mux(p_store_addr(2,1) === UFix(2, 2), Bits("b0011_0000", 8),
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Mux(p_store_addr(2,1) === UFix(3, 2), Bits("b1100_0000", 8),
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UFix(0, 8)))));
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val wmask_w =
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Mux(p_store_addr(2) === UFix(0, 1), Bits("b0000_1111", 8),
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Mux(p_store_addr(2) === UFix(1, 1), Bits("b1111_0000", 8),
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UFix(0, 8)));
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val wmask_d =
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Bits("b1111_1111", 8);
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val store_wmask =
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Mux(p_store_type === MT_B, wmask_b,
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Mux(p_store_type === MT_H, wmask_h,
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Mux(p_store_type === MT_W, wmask_w,
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Mux(p_store_type === MT_D, wmask_d,
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UFix(0, 8)))));
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val store_data =
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Mux(p_store_type === MT_B, Fill(8, p_store_data( 7,0)),
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Mux(p_store_type === MT_H, Fill(4, p_store_data(15,0)),
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Mux(p_store_type === MT_W, Fill(2, p_store_data(31,0)),
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Mux(p_store_type === MT_D, p_store_data,
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UFix(0, 64)))));
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|
||||
val addr_match = (r_cpu_req_addr(tagmsb, offsetlsb) === p_store_addr(tagmsb, offsetlsb));
|
||||
val ldst_conflict = r_cpu_req_val && req_load && p_store_valid && addr_match;
|
||||
val drain_store =
|
||||
(state === s_ready) && p_store_valid &&
|
||||
(!(io.cpu.req_val && (io.cpu.req_cmd === M_XRD)) ||
|
||||
r_cpu_req_val && req_load && p_store_valid && 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;
|
||||
// val db_rdata = Reg(db_array(tag_raddr));
|
||||
val tag_dirty = Reg(db_array(tag_addr)).toBool;
|
||||
|
||||
when (do_store) {
|
||||
when (io.cpu.req_val && io.cpu.req_rdy && req_store) {
|
||||
p_store_idx <== io.cpu.req_idx;
|
||||
p_store_data <== io.cpu.req_data;
|
||||
p_store_type <== io.cpu.req_type;
|
||||
p_store_valid <== Bool(true);
|
||||
}
|
||||
when (drain_store) {
|
||||
p_store_valid <== Bool(false);
|
||||
db_array <== db_array.bitSet(p_store_addr(indexmsb, indexlsb).toUFix, UFix(1,1));
|
||||
db_array <== db_array.bitSet(p_store_idx(PGIDX_BITS-1,offsetbits).toUFix, UFix(1,1));
|
||||
}
|
||||
when (resolve_store) {
|
||||
db_array <== db_array.bitSet(p_store_idx(PGIDX_BITS-1,offsetbits).toUFix, UFix(1,1));
|
||||
}
|
||||
when (tag_we) {
|
||||
db_array <== db_array.bitSet(r_cpu_req_addr(indexmsb, indexlsb).toUFix, UFix(0,1));
|
||||
db_array <== db_array.bitSet(r_cpu_req_idx(PGIDX_BITS-1,offsetbits).toUFix, UFix(0,1));
|
||||
}
|
||||
|
||||
// generate write mask and data signals for stores
|
||||
val storegen = new rocketDCacheStoreGen();
|
||||
storegen.io.req_addr_lsb := p_store_idx(2,0);
|
||||
storegen.io.req_data := p_store_data;
|
||||
storegen.io.req_type := p_store_type
|
||||
val store_data = Fill(2, storegen.io.store_data);
|
||||
val store_wmask_d = storegen.io.store_wmask;
|
||||
val store_idx_sel = p_store_idx(offsetlsb).toBool;
|
||||
val store_wmask =
|
||||
Mux(store_idx_sel,
|
||||
Cat(store_wmask_d, Bits(0,64)),
|
||||
Cat(Bits(0,64), store_wmask_d));
|
||||
|
||||
// data array
|
||||
val data_array = new rocketSRAMsp(lines*4, 128);
|
||||
val store_wmask_expand =
|
||||
Cat(Fill(8, store_wmask(7)),
|
||||
Fill(8, store_wmask(6)),
|
||||
Fill(8, store_wmask(5)),
|
||||
Fill(8, store_wmask(4)),
|
||||
Fill(8, store_wmask(3)),
|
||||
Fill(8, store_wmask(2)),
|
||||
Fill(8, store_wmask(1)),
|
||||
Fill(8, store_wmask(0)));
|
||||
|
||||
val da_store_wmask =
|
||||
Mux(p_store_addr(offsetlsb).toBool,
|
||||
Cat(store_wmask_expand, Bits(0,64)),
|
||||
Cat(Bits(0,64), store_wmask_expand));
|
||||
|
||||
data_array.io.a :=
|
||||
Mux(do_store, p_store_addr(indexmsb, offsetmsb-1),
|
||||
Mux((state === s_writeback) && io.mem.req_rdy, Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count_next),
|
||||
Mux((state === s_start_writeback) || (state === s_writeback) || (state === s_refill), Cat(r_cpu_req_addr(indexmsb, indexlsb), rr_count),
|
||||
Mux((state === s_resolve_miss) || (state === s_replay_load), r_cpu_req_addr(indexmsb, offsetmsb-1),
|
||||
io.cpu.req_addr(indexmsb, offsetmsb-1))))).toUFix;
|
||||
Mux(drain_store || resolve_store, p_store_idx(PGIDX_BITS-1, offsetmsb-1),
|
||||
Mux((state === s_writeback) && io.mem.req_rdy, Cat(r_cpu_req_idx(PGIDX_BITS-1, offsetbits), rr_count_next),
|
||||
Mux((state === s_start_writeback) || (state === s_writeback) || (state === s_refill), Cat(r_cpu_req_idx(PGIDX_BITS-1, offsetbits), rr_count),
|
||||
Mux((state === s_resolve_miss) || (state === s_replay_load), r_cpu_req_idx(PGIDX_BITS-1, offsetmsb-1),
|
||||
io.cpu.req_idx(PGIDX_BITS-1, offsetmsb-1))))).toUFix;
|
||||
|
||||
data_array.io.d :=
|
||||
Mux((state === s_refill), io.mem.resp_data,
|
||||
Cat(store_data, store_data));
|
||||
|
||||
data_array.io.we := ((state === s_refill) && io.mem.resp_val) || do_store;
|
||||
data_array.io.bweb :=
|
||||
Mux((state === s_refill), ~Bits(0,128),
|
||||
da_store_wmask);
|
||||
Mux((state === s_refill), io.mem.resp_data,
|
||||
Mux((state === s_resolve_miss), Fill(2, p_store_data),
|
||||
store_data));
|
||||
data_array.io.we := ((state === s_refill) && io.mem.resp_val) || drain_store || resolve_store;
|
||||
data_array.io.bweb := Mux((state === s_refill), ~Bits(0,128), store_wmask);
|
||||
data_array.io.ce := Bool(true); // FIXME
|
||||
val data_array_rdata = data_array.io.q;
|
||||
|
||||
val miss = (state === s_ready) && r_cpu_req_val && req_load && (!tag_match || (p_store_valid && addr_match));
|
||||
// signal a load miss when the data isn't present in the cache and when it's in the pending store data register
|
||||
// (causes the cache to block for 2 cycles and the load instruction is replayed)
|
||||
val hit = tag_valid && tag_match;
|
||||
val load_miss = (state === s_ready) && r_cpu_req_val && r_req_load && (!hit || (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);
|
||||
// busy when there's a load to the same address as a pending store, or on a cache miss, or when executing a flush
|
||||
io.cpu.req_rdy := (state === s_ready) && !ldst_conflict && (!r_cpu_req_val || (hit && !r_req_flush));
|
||||
io.cpu.resp_val := ((state === s_ready) && r_cpu_req_val && r_req_load && hit && !(p_store_valid && addr_match)) ||
|
||||
((state === s_resolve_miss) && r_req_flush) ||
|
||||
r_cpu_resp_val;
|
||||
|
||||
io.cpu.resp_miss := miss;
|
||||
// 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_tag := Cat(req_ptw_load, r_cpu_req_type, r_cpu_req_addr(2,0), r_cpu_req_tag);
|
||||
io.cpu.resp_miss := load_miss;
|
||||
// tag MSB distinguishes between loads destined for the PTW and CPU
|
||||
io.cpu.resp_tag := Cat(r_req_ptw_load, r_cpu_req_type, r_cpu_req_idx(2,0), r_cpu_req_tag);
|
||||
io.cpu.resp_data :=
|
||||
Mux(r_cpu_req_addr(offsetlsb).toBool, data_array_rdata(127, 64),
|
||||
Mux(r_cpu_req_idx(offsetlsb).toBool, data_array_rdata(127, 64),
|
||||
data_array_rdata(63,0));
|
||||
|
||||
io.mem.req_val := (state === s_req_refill) || (state === s_writeback);
|
||||
@ -306,8 +350,8 @@ class rocketDCacheDM(lines: Int) extends Component {
|
||||
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);
|
||||
Mux(state === s_writeback, Cat(tag_rdata, r_cpu_req_idx(PGIDX_BITS-1, offsetbits), rr_count),
|
||||
Cat(r_cpu_req_ppn, r_cpu_req_idx(PGIDX_BITS-1, offsetbits), Bits(0,2))).toUFix;
|
||||
|
||||
// control state machine
|
||||
switch (state) {
|
||||
@ -318,13 +362,13 @@ class rocketDCacheDM(lines: Int) extends Component {
|
||||
when (ldst_conflict) {
|
||||
state <== s_replay_load;
|
||||
}
|
||||
when (!r_cpu_req_val || tag_match) {
|
||||
when (!r_cpu_req_val || (hit && !r_req_flush)) {
|
||||
state <== s_ready;
|
||||
}
|
||||
when (tag_valid & tag_dirty) {
|
||||
state <== s_start_writeback;
|
||||
}
|
||||
when (req_flush) {
|
||||
when (r_req_flush) {
|
||||
state <== s_resolve_miss;
|
||||
}
|
||||
otherwise {
|
||||
@ -339,8 +383,12 @@ class rocketDCacheDM(lines: Int) extends Component {
|
||||
}
|
||||
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; }
|
||||
when (r_req_flush) {
|
||||
state <== s_resolve_miss;
|
||||
}
|
||||
otherwise {
|
||||
state <== s_req_refill;
|
||||
}
|
||||
}
|
||||
}
|
||||
is (s_req_refill)
|
||||
|
@ -18,11 +18,11 @@ class ioDTLB_CPU(view: List[String] = null) extends Bundle(view)
|
||||
val req_cmd = Bits(4, 'input); // load/store/amo
|
||||
val req_rdy = Bool('output);
|
||||
val req_asid = Bits(ASID_BITS, 'input);
|
||||
val req_addr = UFix(VADDR_BITS, 'input);
|
||||
val req_vpn = UFix(VPN_BITS, 'input);
|
||||
// lookup responses
|
||||
val resp_miss = Bool('output);
|
||||
val resp_val = Bool('output);
|
||||
val resp_addr = UFix(PADDR_BITS, 'output);
|
||||
// val resp_val = Bool('output);
|
||||
val resp_ppn = UFix(PPN_BITS, 'output);
|
||||
val xcpt_ld = Bool('output);
|
||||
val xcpt_st = Bool('output);
|
||||
}
|
||||
@ -35,25 +35,40 @@ class ioDTLB extends Bundle
|
||||
|
||||
class rocketDTLB(entries: Int) extends Component
|
||||
{
|
||||
val addr_bits = ceil(log10(entries)/log10(2)).toInt;
|
||||
val io = new ioDTLB();
|
||||
|
||||
val addr_bits = ceil(log10(entries)/log10(2)).toInt;
|
||||
|
||||
val s_ready :: s_request :: s_wait :: Nil = Enum(3) { UFix() };
|
||||
val state = Reg(resetVal = s_ready);
|
||||
|
||||
val tag_cam = new rocketCAM(entries, addr_bits, ASID_BITS+VPN_BITS);
|
||||
|
||||
val req_vpn = io.cpu.req_addr(VADDR_BITS-1,PGIDX_BITS);
|
||||
val req_idx = io.cpu.req_addr(PGIDX_BITS-1,0);
|
||||
val req_load = (io.cpu.req_cmd === M_XRD);
|
||||
val req_store = (io.cpu.req_cmd === M_XWR);
|
||||
val r_cpu_req_vpn = Reg(resetVal = Bits(0, VPN_BITS));
|
||||
val r_cpu_req_val = Reg(resetVal = Bool(false));
|
||||
val r_cpu_req_cmd = Reg(resetVal = Bits(0,4));
|
||||
val r_cpu_req_asid = Reg(resetVal = Bits(0,ASID_BITS));
|
||||
val r_refill_tag = Reg(resetVal = Bits(0,ASID_BITS+VPN_BITS));
|
||||
val r_refill_waddr = Reg(resetVal = UFix(0,addr_bits));
|
||||
val repl_count = Reg(resetVal = UFix(0,addr_bits));
|
||||
|
||||
when (io.cpu.req_val && io.cpu.req_rdy) {
|
||||
r_cpu_req_vpn <== io.cpu.req_vpn;
|
||||
r_cpu_req_cmd <== io.cpu.req_cmd;
|
||||
r_cpu_req_asid <== io.cpu.req_asid;
|
||||
}
|
||||
|
||||
when (io.cpu.req_rdy) {
|
||||
r_cpu_req_val <== io.cpu.req_val;
|
||||
}
|
||||
|
||||
// val req_vpn = r_cpu_req_addr(VADDR_BITS-1,PGIDX_BITS);
|
||||
// val req_idx = io.cpu.req_addr(PGIDX_BITS-1,0);
|
||||
val req_load = (r_cpu_req_cmd === M_XRD);
|
||||
val req_store = (r_cpu_req_cmd === M_XWR);
|
||||
// val req_amo = io.cpu.req_cmd(3).toBool;
|
||||
|
||||
val lookup_tag = Cat(io.cpu.req_asid, req_vpn);
|
||||
val r_refill_tag = Reg(resetVal = Bits(0, ASID_BITS+VPN_BITS));
|
||||
val r_refill_waddr = Reg(resetVal = UFix(0, addr_bits));
|
||||
val repl_count = Reg(resetVal = UFix(0, addr_bits));
|
||||
|
||||
val lookup_tag = Cat(r_cpu_req_asid, r_cpu_req_vpn);
|
||||
|
||||
val tag_cam = new rocketCAM(entries, addr_bits, ASID_BITS+VPN_BITS);
|
||||
val tag_ram = Mem(entries, io.ptw.resp_val, r_refill_waddr.toUFix, io.ptw.resp_ppn);
|
||||
|
||||
tag_cam.io.clear := io.cpu.invalidate;
|
||||
@ -61,6 +76,7 @@ class rocketDTLB(entries: Int) extends Component
|
||||
tag_cam.io.write := io.ptw.resp_val;
|
||||
tag_cam.io.write_tag := r_refill_tag;
|
||||
tag_cam.io.write_addr := r_refill_waddr;
|
||||
val tag_hit = tag_cam.io.hit;
|
||||
val tag_hit_addr = tag_cam.io.hit_addr;
|
||||
|
||||
// extract fields from status register
|
||||
@ -75,10 +91,10 @@ class rocketDTLB(entries: Int) extends Component
|
||||
val ptw_perm_sw = io.ptw.resp_perm(5);
|
||||
|
||||
// permission bit arrays
|
||||
val ur_array = Reg(resetVal = Bits(0, entries)); // user execute permission
|
||||
val uw_array = Reg(resetVal = Bits(0, entries)); // user execute permission
|
||||
val sr_array = Reg(resetVal = Bits(0, entries)); // supervisor execute permission
|
||||
val sw_array = Reg(resetVal = Bits(0, entries)); // supervisor execute permission
|
||||
val ur_array = Reg(resetVal = Bits(0, entries)); // user read permission
|
||||
val uw_array = Reg(resetVal = Bits(0, entries)); // user write permission
|
||||
val sr_array = Reg(resetVal = Bits(0, entries)); // supervisor read permission
|
||||
val sw_array = Reg(resetVal = Bits(0, entries)); // supervisor write permission
|
||||
when (io.ptw.resp_val) {
|
||||
ur_array <== ur_array.bitSet(r_refill_waddr, ptw_perm_ur);
|
||||
uw_array <== uw_array.bitSet(r_refill_waddr, ptw_perm_uw);
|
||||
@ -103,12 +119,13 @@ class rocketDTLB(entries: Int) extends Component
|
||||
|
||||
val repl_waddr = Mux(invalid_entry, ie_addr, repl_count).toUFix;
|
||||
|
||||
val lookup_hit = (state === s_ready) && io.cpu.req_val && tag_cam.io.hit;
|
||||
val lookup_miss = (state === s_ready) && io.cpu.req_val && !tag_cam.io.hit;
|
||||
|
||||
val lookup_hit = (state === s_ready) && r_cpu_req_val && tag_hit;
|
||||
val lookup_miss = (state === s_ready) && r_cpu_req_val && !tag_hit;
|
||||
val tlb_hit = status_vm && lookup_hit;
|
||||
val tlb_miss = status_vm && lookup_miss;
|
||||
|
||||
// currently replace TLB entries in LIFO order
|
||||
// TODO: implement LRU replacement policy
|
||||
when (tlb_miss) {
|
||||
r_refill_tag <== lookup_tag;
|
||||
r_refill_waddr <== repl_waddr;
|
||||
@ -130,10 +147,7 @@ class rocketDTLB(entries: Int) extends Component
|
||||
|
||||
io.cpu.req_rdy := (state === s_ready);
|
||||
io.cpu.resp_miss := tlb_miss;
|
||||
io.cpu.resp_val := Mux(status_vm, lookup_hit, io.cpu.req_val);
|
||||
io.cpu.resp_addr :=
|
||||
Mux(status_vm, Cat(tag_ram(tag_hit_addr), req_idx),
|
||||
io.cpu.req_addr(PADDR_BITS-1,0)).toUFix;
|
||||
io.cpu.resp_ppn := Mux(status_vm, tag_ram(tag_hit_addr), r_cpu_req_vpn(PPN_BITS-1,0)).toUFix;
|
||||
|
||||
io.ptw.req_val := (state === s_request);
|
||||
io.ptw.req_vpn := r_refill_tag(VPN_BITS-1,0);
|
||||
|
@ -7,7 +7,7 @@ import scala.math._;
|
||||
|
||||
class ioDmemArbiter extends Bundle
|
||||
{
|
||||
val ptw = new ioDmem(List("req_val", "req_rdy", "req_cmd", "req_type", "req_addr", "resp_data", "resp_val"));
|
||||
val ptw = new ioDmem(List("req_val", "req_rdy", "req_cmd", "req_type", "req_idx", "req_ppn", "resp_data", "resp_val"));
|
||||
val cpu = new ioDmem();
|
||||
val mem = new ioDmem().flip();
|
||||
}
|
||||
@ -19,7 +19,8 @@ class rocketDmemArbiter extends Component
|
||||
io.mem.req_val := io.ptw.req_val || io.cpu.req_val;
|
||||
io.mem.req_cmd := Mux(io.ptw.req_val, io.ptw.req_cmd, io.cpu.req_cmd);
|
||||
io.mem.req_type := Mux(io.ptw.req_val, io.ptw.req_type, io.cpu.req_type);
|
||||
io.mem.req_addr := Mux(io.ptw.req_val, io.ptw.req_addr, io.cpu.req_addr);
|
||||
io.mem.req_idx := Mux(io.ptw.req_val, io.ptw.req_idx, io.cpu.req_idx);
|
||||
io.mem.req_ppn := Mux(io.ptw.req_val, io.ptw.req_ppn, io.cpu.req_ppn);
|
||||
io.mem.req_data := io.cpu.req_data;
|
||||
io.mem.req_tag := Mux(io.ptw.req_val, Bits(0,5), io.cpu.req_tag);
|
||||
|
||||
@ -40,7 +41,7 @@ class ioPTW extends Bundle
|
||||
{
|
||||
val itlb = new ioTLB_PTW().flip();
|
||||
val dtlb = new ioTLB_PTW().flip();
|
||||
val dmem = new ioDmem(List("req_val", "req_rdy", "req_cmd", "req_type", "req_addr", "resp_data", "resp_val")).flip();
|
||||
val dmem = new ioDmem(List("req_val", "req_rdy", "req_cmd", "req_type", "req_ppn", "req_idx", "resp_data", "resp_val")).flip();
|
||||
val ptbr = UFix(PADDR_BITS, 'input);
|
||||
}
|
||||
|
||||
@ -90,7 +91,9 @@ class rocketPTW extends Component
|
||||
|
||||
io.dmem.req_cmd := M_PRD;
|
||||
io.dmem.req_type := MT_D;
|
||||
io.dmem.req_addr := req_addr;
|
||||
// io.dmem.req_addr := req_addr;
|
||||
io.dmem.req_idx := req_addr(PGIDX_BITS-1,0);
|
||||
io.dmem.req_ppn := req_addr(PADDR_BITS-1,PGIDX_BITS);
|
||||
|
||||
val resp_val = (state === s_done) || (state === s_l1_fake) || (state === s_l2_fake);
|
||||
val resp_err = (state === s_error);
|
||||
|
Loading…
Reference in New Issue
Block a user