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@@ -50,7 +50,7 @@ import CCTypes::*;
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import L1CoCache::*;
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import MMIOInst::*;
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`ifdef RVFI_DII
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import RVFI_DII::*;
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import RVFI_DII_Types::*;
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import Types::*;
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`endif
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@@ -92,7 +92,8 @@ interface FetchStage;
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// debug
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method FetchDebugState getFetchState;
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`ifdef RVFI_DII
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interface Client#(Dii_Id, InstsAndIDs) dii;
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interface Client#(Dii_Ids, InstsAndIDs) dii;
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method Action lastTraceId(Dii_Id in);
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`endif
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// performance
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@@ -303,7 +304,7 @@ module mkFetchStage(FetchStage);
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// rule ordering: Fetch1 (BTB+TLB) < Fetch3 (decode & dir pred) < redirect method
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// Fetch1 < Fetch3 to avoid bypassing path on PC and epochs
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Bool verbose = False;
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Bool verbose = True;
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Integer verbosity = 1;
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// Basic State Elements
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@@ -329,13 +330,13 @@ module mkFetchStage(FetchStage);
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Integer pc_redirect_port = 2;
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// Epochs
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Reg#(Bool) decode_epoch <- mkReg(False);
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Ehr#(2, Bool) decode_epoch <- mkEhr(False);
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Reg#(Epoch) f_main_epoch <- mkReg(0); // fetch estimate of main epoch
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// Regs to hold the first half of an instruction that straddles a cache line boundary
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Reg #(Bool) rg_pending_straddle <- mkReg (False);
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Reg #(Addr) rg_half_inst_pc <- mkRegU; // The PC of the straddling instruction
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Reg #(Bit #(16)) rg_half_inst_lsbs <- mkRegU; // The 16 lsbs of the straddling instruction
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// Regs/wires to hold the first half of an instruction that straddles a cache line boundary
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Ehr #(3, Bool) ehr_pending_straddle <- mkEhr (False);
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Ehr #(2, Addr) ehr_half_inst_pc <- mkEhr (?); // The PC of the straddling instruction
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Ehr #(2, Bit #(16)) ehr_half_inst_lsbs <- mkEhr (?); // The 16 lsbs of the straddling instruction
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// Pipeline Stage FIFOs
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Fifo#(2, Tuple2#(Bit#(TLog#(SupSize)),Fetch1ToFetch2)) f12f2 <- mkCFFifo;
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@@ -394,21 +395,31 @@ module mkFetchStage(FetchStage);
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`endif
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`ifdef RVFI_DII
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Fifo#(2, Dii_Id) dii_instIds <- mkCFFifo;
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Fifo#(2, Dii_Ids) dii_instIds <- mkCFFifo;
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Fifo#(2, InstsAndIDs) dii_insts <- mkCFFifo;
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FIFOF#(Dii_Id) flush_id <- mkUGFIFOF1; // Next sequence number to request when trapping
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Reg#(Dii_Id) dii_id_next <- mkReg(0);
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Reg#(Dii_Id) last_trace_id <- mkRegU;
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rule feed_dii;
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rule feed_dii(!waitForFlush);
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Dii_Id next_id = dii_id_next;
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if (flush_id.notEmpty) begin
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dii_instIds.enq(flush_id.first);
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if (verbosity > 0) $display("Requested from %d DII", flush_id.first);
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next_id = flush_id.first;
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if (verbosity > 0) $display("DII flushed!");
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flush_id.deq;
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end else begin
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dii_instIds.enq(dii_id_next);
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if (verbosity > 0) $display("Requested from %d DII", dii_id_next);
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dii_id_next <= dii_id_next + 1;
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end
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Dii_Ids reqs = replicate(tagged Invalid);
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for (Integer i = 0; i < `sizeSup; i = i + 1)
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reqs[i] = tagged Valid (next_id + fromInteger(i));
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if (verbosity > 0) $display("Requested from DII", fshow(reqs));
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dii_instIds.enq(reqs);
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dii_id_next <= next_id + `sizeSup;
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endrule
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Reg#(Bit#(4)) ticker <- mkReg(0);
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rule tick;
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ticker <= ticker + 4;
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if (ticker == 0) $display("%t : tick", $time);
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endrule
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`endif
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@@ -483,7 +494,7 @@ module mkFetchStage(FetchStage);
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let out = Fetch1ToFetch2 {
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pc: pc,
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pred_next_pc: pred_next_pc,
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decode_epoch: decode_epoch,
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decode_epoch: decode_epoch[0],
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main_epoch: f_main_epoch};
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f12f2.enq(tuple2(fromInteger(posLastSup),out));
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if (verbose) $display("Fetch1: ", fshow(out));
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@@ -499,6 +510,7 @@ module mkFetchStage(FetchStage);
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// Access main mem or boot rom if no TLB exception
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Bool access_mmio = False;
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`ifndef RVFI_DII
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if (!isValid(cause)) begin
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case(mmio.getFetchTarget(phys_pc))
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MainMem: begin
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@@ -524,6 +536,7 @@ module mkFetchStage(FetchStage);
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Addr align32b_mask = 'h3;
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tval = (in.pc & (~ align32b_mask));
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end
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`endif
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let out = Fetch2ToFetch3 {
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pc: in.pc,
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@@ -542,14 +555,22 @@ module mkFetchStage(FetchStage);
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$display ("Fetch2: f2_tof3.enq: nbSup %0d out ", nbSup, fshow (out));
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end
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endrule
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// Break out of i$
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rule doFetch3;
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let {nbSup, fetch3In} = f22f3.first;
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f22f3.deq();
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if (verbosity > 0)
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$display("Fetch3: fetch3In: ", fshow (fetch3In));
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`ifdef RVFI_DII
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Vector#(SupSize,Maybe#(Instruction)) inst_d = replicate(tagged Valid dii_nop);
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if (fetch3In.main_epoch == f_main_epoch) begin
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InstsAndIDs ii <- toGet(dii_insts).get();
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inst_d = ii.insts;
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if (verbosity > 0) $display("Got from DII: ", fshow (inst_d));
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end
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`else
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// Get ICache/MMIO response if no exception
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// In case of exception, we still need to process at least inst_data[0]
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// (it will be turned to an exception later), so inst_data[0] must be
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@@ -557,27 +578,21 @@ module mkFetchStage(FetchStage);
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Vector#(SupSize,Maybe#(Instruction)) inst_d = replicate(tagged Valid (0));
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if(!isValid(fetch3In.cause)) begin
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if(fetch3In.access_mmio) begin
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if(verbose) $display("get answer from MMIO %d", fetch3In.pc);
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if(verbose) $display("get answer from MMIO %x", fetch3In.pc);
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inst_d <- mmio.bootRomResp;
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end
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else begin
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if(verbose) $display("get answer from memory %d", fetch3In.pc);
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if(verbose) $display("get answer from memory %x", fetch3In.pc);
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inst_d <- mem_server.response.get;
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end
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end
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`ifdef RVFI_DII
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InstsAndIDs ii <- toGet(dii_insts).get();
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inst_d = ii.insts;
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if (verbosity > 0)
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$display("Got from DII: ", fshow (inst_d));
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`endif
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if (fetch3In.decode_epoch != decode_epoch) begin
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if (fetch3In.decode_epoch != decode_epoch[1]) begin
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// Just drop it.
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if (verbosity > 0) begin
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$display ("----------------");
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$display ("Fetch3: Drop: decode epoch: %d", decode_epoch);
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$display ("Fetch3: Drop: decode epoch: %d", decode_epoch[1]);
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$display ("Fetch3: f22f3.first: ", fshow (f22f3.first));
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$display ("Fetch3: inst_d: ", fshow (inst_d));
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end
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@@ -588,8 +603,8 @@ module mkFetchStage(FetchStage);
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Addr start_PC = fetch3In.pc;
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// Handle cache-line boundary straddling instruction, if one is pending
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if (rg_pending_straddle) begin
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if (fetch3In.pc != rg_half_inst_pc + 4) begin
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if (ehr_pending_straddle[1]) begin
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if (fetch3In.pc != ehr_half_inst_pc[1] + 4) begin
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$display ("----------------");
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$display ("Fetch3: straddle: pc mismatch");
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$display ("Fetch3: f22f3.first: ", fshow (f22f3.first));
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@@ -598,17 +613,17 @@ module mkFetchStage(FetchStage);
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end
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else begin
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// Prepend onto the sequence: { first-half of the instruction , 0 }
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v_x16 = shiftInAt0 (shiftInAt0 (v_x16, rg_half_inst_lsbs), 0);
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v_x16 = shiftInAt0 (shiftInAt0 (v_x16, ehr_half_inst_lsbs[1]), 0);
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let bound = valueOf (SupSizeX2) - 1;
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if (n_x16s < (fromInteger (bound) - 1))
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n_x16s = n_x16s + 2;
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else if (n_x16s < fromInteger (bound))
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n_x16s = n_x16s + 1;
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start_PC = rg_half_inst_pc;
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rg_pending_straddle <= False;
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start_PC = ehr_half_inst_pc[1];
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ehr_pending_straddle[1] <= False;
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if (verbosity > 0) begin
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$display ("----------------");
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$display ("Fetch3: straddle: prepend x16 %0h", rg_half_inst_lsbs);
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$display ("Fetch3: straddle: prepend x16 %0h", ehr_half_inst_lsbs[1]);
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$display ("Fetch3: f22f3.first: ", fshow (f22f3.first));
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$display ("Fetch3: inst_d: ", fshow (inst_d));
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$display ("Fetch3: v_x16: ", fshow (v_x16));
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@@ -640,7 +655,7 @@ module mkFetchStage(FetchStage);
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// The main_epoch check is required to make sure this stage doesn't
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// redirect the PC if a later stage already redirected the PC.
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if (fetch3In.main_epoch == f_main_epoch) begin
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Bool decode_epoch_local = decode_epoch; // next value for decode epoch
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Bool decode_epoch_local = decode_epoch[0]; // next value for decode epoch
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Maybe#(Addr) redirectPc = Invalid; // next pc redirect by branch predictor
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Maybe#(TrainNAP) trainNAP = Invalid; // training data sent to next addr pred
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`ifdef PERF_COUNT
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@@ -653,9 +668,9 @@ module mkFetchStage(FetchStage);
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if ((inst_data[i].inst_kind == Inst_32b_Lsbs) && (fromInteger(i) <= nbSup)) begin
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if (fetch3In.decode_epoch == decode_epoch_local) begin
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// Save the half-instruction and redirect doFetch1 to get the next cache line
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rg_pending_straddle <= True;
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rg_half_inst_pc <= inst_data[i].pc;
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rg_half_inst_lsbs <= inst_data[i].orig_inst [15:0];
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ehr_pending_straddle[0] <= True;
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ehr_half_inst_pc[0] <= inst_data[i].pc;
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ehr_half_inst_lsbs[0] <= inst_data[i].orig_inst [15:0];
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decode_epoch_local = ! decode_epoch_local;
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let next_PC = inst_data[i].pc + 4;
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redirectPc = tagged Valid (next_PC);
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@@ -763,7 +778,7 @@ module mkFetchStage(FetchStage);
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ras.ras[i].popPush(False, Valid (push_addr));
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end
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end
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end
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end
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if(verbose) begin
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$display("Branch prediction: ", fshow(dInst.iType), " ; ", fshow(in.pc), " ; ",
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@@ -816,7 +831,7 @@ module mkFetchStage(FetchStage);
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if(redirectPc matches tagged Valid .nextPc) begin
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pc_reg[pc_decode_port] <= nextPc;
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end
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decode_epoch <= decode_epoch_local;
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decode_epoch[0] <= decode_epoch_local;
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// send training data for next addr pred
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if (trainNAP matches tagged Valid .x) begin
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napTrainByDecQ.enq(x);
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@@ -887,6 +902,7 @@ module mkFetchStage(FetchStage);
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if (verbose) $display("Redirect: newpc %h, old f_main_epoch %d, new f_main_epoch %d",new_pc,f_main_epoch,f_main_epoch+1);
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pc_reg[pc_redirect_port] <= new_pc;
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f_main_epoch <= (f_main_epoch == fromInteger(valueOf(NumEpochs)-1)) ? 0 : f_main_epoch + 1;
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ehr_pending_straddle[2] <= False;
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// redirect comes, stop stalling for redirect
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waitForRedirect <= False;
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setWaitRedirect_redirect_conflict.wset(?); // conflict with setWaitForRedirect
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@@ -896,7 +912,19 @@ module mkFetchStage(FetchStage);
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endmethod
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method Action done_flushing() if (waitForFlush);
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// signal that the pipeline can resume fetching
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waitForFlush <= False;
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`ifdef RVFI_DII
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if (dii_insts.notEmpty) begin
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dii_insts.deq;
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if (verbose) $display("%t : Flushing; dequing dii_insts",$time());
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end else begin
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flush_id.enq(last_trace_id + 1);
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`endif
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waitForFlush <= False;
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if (verbose) $display("%t : Done Flushing",$time());
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`ifdef RVFI_DII
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end
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`endif
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// XXX The guard prevents the readyToFetch rule in Core.bsv from firing every cycle
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// The guard also makes this method sequence before (restricted) redirect method
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// So the effect of setting waitForFlush in redirect method will not be overwritten
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@@ -985,6 +1013,9 @@ module mkFetchStage(FetchStage);
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interface Get request = toGet(dii_instIds);
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interface Put response = toPut(dii_insts);
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endinterface
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method Action lastTraceId(Dii_Id in);
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last_trace_id <= in;
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endmethod
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`endif
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endmodule
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