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Optimizations to cclsm.

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This commit is contained in:
Rose Thompson 2023-11-28 14:18:06 -06:00
parent 0229df4a0f
commit 4d4790ecf9
1 changed files with 14 additions and 15 deletions
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29
src/lsu/align.sv
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@ -65,12 +65,12 @@ module align import cvw::*; #(parameter cvw_t P) (
typedef enum logic [1:0] {STATE_READY, STATE_SPILL, STATE_STORE_DELAY} statetype;
statetype CurrState, NextState;
logic TakeSpillM;
logic ValidSpillM;
logic SpillM;
logic SelSpillM;
logic SpillSaveM;
logic [P.LLEN-1:0] ReadDataWordFirstHalfM;
logic MisalignedM;
logic ValidMisalignedM, MisalignedM;
logic [P.LLEN*2-1:0] ReadDataWordSpillAllM;
logic [P.LLEN*2-1:0] ReadDataWordSpillShiftedM;
@ -78,7 +78,6 @@ module align import cvw::*; #(parameter cvw_t P) (
logic [(P.LLEN-1)*2/8:0] ByteMaskSaveM;
logic [(P.LLEN-1)*2/8:0] ByteMaskMuxM;
logic SaveByteMask;
logic HalfMisalignedM, WordMisalignedM;
logic [OFFSET_BIT_POS-1:$clog2(LLENINBYTES)] WordOffsetM;
logic [$clog2(LLENINBYTES)-1:0] ByteOffsetM;
@ -118,7 +117,7 @@ module align import cvw::*; #(parameter cvw_t P) (
assign WordMisalignedM = (ByteOffsetM[1:0] != '0) & Funct3M[1:0] == 2'b10;
assign HalfSpillM = (IEUAdrM[OFFSET_BIT_POS-1:1] == '1) & HalfMisalignedM;
assign WordSpillM = (IEUAdrM[OFFSET_BIT_POS-1:2] == '1) & WordMisalignedM;
assign ValidAccess = (|MemRWM) & ~SelHPTW;
assign ValidAccess = (|MemRWM);
if(P.LLEN == 64) begin
logic DoubleSpillM;
@ -126,15 +125,16 @@ module align import cvw::*; #(parameter cvw_t P) (
assign DoubleMisalignedM = (ByteOffsetM[2:0] != '0) & Funct3M[1:0] == 2'b11;
assign DoubleSpillM = (IEUAdrM[OFFSET_BIT_POS-1:3] == '1) & DoubleMisalignedM;
assign MisalignedM = ValidAccess & (HalfMisalignedM | WordMisalignedM | DoubleMisalignedM);
assign SpillM = ValidAccess & CacheableM & (HalfSpillM | WordSpillM | DoubleSpillM);
assign SpillM = ValidAccess & (HalfSpillM | WordSpillM | DoubleSpillM);
end else begin
assign SpillM = ValidAccess & CacheableM & (HalfSpillM | WordSpillM);
assign SpillM = ValidAccess & (HalfSpillM | WordSpillM);
assign MisalignedM = ValidAccess & (HalfMisalignedM | WordMisalignedM);
end
// align by shifting
// Don't take the spill if there is a stall, TLB miss, or hardware update to the D/A bits
assign TakeSpillM = SpillM & ~CacheBusHPWTStall & ~(DTLBMissM | (P.SVADU_SUPPORTED & DataUpdateDAM));
assign ValidSpillM = SpillM & ~CacheBusHPWTStall;
assign ValidMisalignedM = MisalignedM & ~SelHPTW;
always_ff @(posedge clk)
if (reset | FlushM) CurrState <= #1 STATE_READY;
@ -142,8 +142,8 @@ module align import cvw::*; #(parameter cvw_t P) (
always_comb begin
case (CurrState)
STATE_READY: if (TakeSpillM & ~MemRWM[0]) NextState = STATE_SPILL;
else if(TakeSpillM & MemRWM[0])NextState = STATE_STORE_DELAY;
STATE_READY: if (ValidSpillM & ~MemRWM[0]) NextState = STATE_SPILL;
else if(ValidSpillM & MemRWM[0])NextState = STATE_STORE_DELAY;
else NextState = STATE_READY;
STATE_SPILL: if(StallM) NextState = STATE_SPILL;
else NextState = STATE_READY;
@ -153,9 +153,8 @@ module align import cvw::*; #(parameter cvw_t P) (
end
assign SelSpillM = (CurrState == STATE_SPILL | CurrState == STATE_STORE_DELAY);
assign SelSpillE = (CurrState == STATE_READY & TakeSpillM) | (CurrState == STATE_SPILL & CacheBusHPWTStall) | (CurrState == STATE_STORE_DELAY);
assign SaveByteMask = (CurrState == STATE_READY & TakeSpillM);
assign SpillSaveM = (CurrState == STATE_READY) & TakeSpillM & ~FlushM;
assign SelSpillE = (CurrState == STATE_READY & ValidSpillM) | (CurrState == STATE_SPILL & CacheBusHPWTStall) | (CurrState == STATE_STORE_DELAY);
assign SpillSaveM = (CurrState == STATE_READY) & ValidSpillM & ~FlushM;
assign SelStoreDelay = (CurrState == STATE_STORE_DELAY); // *** Can this be merged into the PreLSURWM logic?
assign SpillStallM = SelSpillE | CurrState == STATE_STORE_DELAY;
mux2 #(2) memrwmux(MemRWM, 2'b00, SelStoreDelay, MemRWSpillM);
@ -173,14 +172,14 @@ module align import cvw::*; #(parameter cvw_t P) (
// shifter (4:1 mux for 32 bit, 8:1 mux for 64 bit)
// 8 * is for shifting by bytes not bits
assign ReadDataWordSpillShiftedM = ReadDataWordSpillAllM >> (MisalignedM ? 8 * AccessByteOffsetM : '0);
assign ReadDataWordSpillShiftedM = ReadDataWordSpillAllM >> (ValidMisalignedM ? 8 * AccessByteOffsetM : '0);
assign DCacheReadDataWordSpillM = ReadDataWordSpillShiftedM[P.LLEN-1:0];
// write path. Also has the 8:1 shifter muxing for the byteoffset
// then it also has the mux to select when a spill occurs
logic [P.LLEN*3-1:0] LSUWriteDataShiftedExtM; // *** RT: Find a better way. I've extending in both directions so we don't shift in zeros. The cache expects the writedata to not have any zero data, but instead replicated data.
assign LSUWriteDataShiftedExtM = {LSUWriteDataM, LSUWriteDataM, LSUWriteDataM} << (MisalignedM ? 8 * AccessByteOffsetM : '0);
assign LSUWriteDataShiftedExtM = {LSUWriteDataM, LSUWriteDataM, LSUWriteDataM} << (ValidMisalignedM ? 8 * AccessByteOffsetM : '0);
assign LSUWriteDataSpillM = LSUWriteDataShiftedExtM[P.LLEN*3-1:P.LLEN];
mux3 #(2*P.LLEN/8) bytemaskspillmux(ByteMaskMuxM, // no spill
@ -188,6 +187,6 @@ module align import cvw::*; #(parameter cvw_t P) (
{{{P.LLEN/8}{1'b0}}, ByteMaskMuxM[P.LLEN*2/8-1:P.LLEN/8]}, // spill, second half
{SelSpillM, SelSpillE}, ByteMaskSpillM);
flopenr #(P.LLEN*2/8) bytemaskreg(clk, reset, SaveByteMask, {ByteMaskExtendedM, ByteMaskM}, ByteMaskSaveM);
flopenr #(P.LLEN*2/8) bytemaskreg(clk, reset, SpillSaveM, {ByteMaskExtendedM, ByteMaskM}, ByteMaskSaveM);
mux2 #(P.LLEN*2/8) bytemasksavemux({ByteMaskExtendedM, ByteMaskM}, ByteMaskSaveM, SelSpillM, ByteMaskMuxM);
endmodule