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Optimized the ebu's beat counting.

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This commit is contained in:
Ross Thompson 2022-10-05 10:58:23 -05:00
parent beb954ae27
commit ea70e1c598
1 changed files with 13 additions and 15 deletions
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28
pipelined/src/ebu/ebu.sv
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@ -94,7 +94,7 @@ module ebu
logic BeatCntEn; logic BeatCntEn;
logic [4-1:0] NextBeatCount, BeatCount, BeatCountDelayed; logic [4-1:0] NextBeatCount, BeatCount, BeatCountDelayed;
logic FinalBeat; logic FinalBeat, FinalBeatD;
logic [2:0] LocalBurstType; logic [2:0] LocalBurstType;
logic CntReset; logic CntReset;
logic [3:0] Threshold; logic [3:0] Threshold;
@ -145,7 +145,7 @@ module ebu
case (CurrState) case (CurrState)
IDLE: if (both) NextState = ARBITRATE; IDLE: if (both) NextState = ARBITRATE;
else NextState = IDLE; else NextState = IDLE;
ARBITRATE: if (HREADY & FinalBeat & ~(LSUReq & IFUReq)) NextState = IDLE; ARBITRATE: if (HREADY & FinalBeatD & ~(LSUReq & IFUReq)) NextState = IDLE;
else NextState = ARBITRATE; else NextState = ARBITRATE;
default: NextState = IDLE; default: NextState = IDLE;
endcase endcase
@ -154,31 +154,29 @@ module ebu
// Controller needs to count beats. // Controller needs to count beats.
flopenr #(4) flopenr #(4)
BeatCountReg(.clk(HCLK), BeatCountReg(.clk(HCLK),
.reset(~HRESETn | CntReset | FinalBeat), .reset(~HRESETn | CntReset | FinalBeatD),
.en(BeatCntEn), .en(BeatCntEn),
.d(NextBeatCount), .d(NextBeatCount),
.q(BeatCount)); .q(BeatCount));
// Used to store data from data phase of AHB.
flopenr #(4)
BeatCountDelayedReg(.clk(HCLK),
.reset(~HRESETn | CntReset),
.en(BeatCntEn),
.d(BeatCount),
.q(BeatCountDelayed));
assign NextBeatCount = BeatCount + 1'b1; assign NextBeatCount = BeatCount + 1'b1;
assign CntReset = NextState == IDLE; assign CntReset = NextState == IDLE;
assign FinalBeat = (BeatCountDelayed == Threshold); // Detect when we are waiting on the final access. assign FinalBeat = (BeatCount == Threshold); // Detect when we are waiting on the final access.
assign BeatCntEn = (NextState == ARBITRATE & HREADY); assign BeatCntEn = (NextState == ARBITRATE & HREADY);
logic [2:0] HBURSTD; logic [2:0] HBURSTD;
flopenr #(3) HBURSTReg(.clk(HCLK), .reset(~HRESETn), .en(HTRANS == 2'b10), .d(HBURST), .q(HBURSTD)); // Used to store data from data phase of AHB.
flopenr #(1)
FinalBeatReg(.clk(HCLK),
.reset(~HRESETn | CntReset),
.en(BeatCntEn),
.d(FinalBeat),
.q(FinalBeatD));
// unlike the bus fsm in lsu/ifu, we need to derive the number of beats from HBURST. // unlike the bus fsm in lsu/ifu, we need to derive the number of beats from HBURST.
always_comb begin always_comb begin
case(HBURSTD) case(HBURST)
0: Threshold = 4'b0000; 0: Threshold = 4'b0000;
3: Threshold = 4'b0011; // INCR4 3: Threshold = 4'b0011; // INCR4
5: Threshold = 4'b0111; // INCR8 5: Threshold = 4'b0111; // INCR8
@ -196,7 +194,7 @@ module ebu
assign IFUDisable = CurrState == ARBITRATE; assign IFUDisable = CurrState == ARBITRATE;
assign IFUSelect = (NextState == ARBITRATE) ? 1'b0 : IFUReq; assign IFUSelect = (NextState == ARBITRATE) ? 1'b0 : IFUReq;
// Controller 1 (LSU) // Controller 1 (LSU)
assign LSUDisable = CurrState == ARBITRATE ? 1'b0 : (IFUReqD & ~(HREADY & FinalBeat)); assign LSUDisable = CurrState == ARBITRATE ? 1'b0 : (IFUReqD & ~(HREADY & FinalBeatD));
assign LSUSelect = NextState == ARBITRATE ? 1'b1: LSUReq; assign LSUSelect = NextState == ARBITRATE ? 1'b1: LSUReq;
flopr #(1) ifureqreg(clk, ~HRESETn, IFUReq, IFUReqD); flopr #(1) ifureqreg(clk, ~HRESETn, IFUReq, IFUReqD);