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changed ahb FSM and caught potential bug in ack/wordcountthreshold when on last word

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slmnemo 2022-05-26 18:41:27 -07:00
parent efce3e4953
commit bddc32ed21
2 changed files with 11 additions and 11 deletions
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18
pipelined/src/ebu/ahblite.sv
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@ -111,13 +111,13 @@ module ahblite (
else if (LSUBusWrite)NextBusState = MEMWRITE; else if (LSUBusWrite)NextBusState = MEMWRITE;
else if (IFUBusRead) NextBusState = INSTRREAD; else if (IFUBusRead) NextBusState = INSTRREAD;
else NextBusState = IDLE; else NextBusState = IDLE;
MEMREAD: if (~HREADY) NextBusState = MEMREAD; MEMREAD: if (~LSUBurstDone) NextBusState = MEMREAD;
else if (IFUBusRead) NextBusState = INSTRREAD; else if (IFUBusRead & LSUBurstDone) NextBusState = INSTRREAD;
else NextBusState = IDLE; else NextBusState = IDLE;
MEMWRITE: if (~HREADY) NextBusState = MEMWRITE; MEMWRITE: if (~LSUBurstDone) NextBusState = MEMWRITE;
else if (IFUBusRead) NextBusState = INSTRREAD; else if (IFUBusRead & LSUBurstDone) NextBusState = INSTRREAD;
else NextBusState = IDLE; else NextBusState = IDLE;
INSTRREAD: if (~HREADY) NextBusState = INSTRREAD; INSTRREAD: if (~IFUBurstDone) NextBusState = INSTRREAD; // *** think about moving to memread/write if LSUBusRead/Write are high
else NextBusState = IDLE; // if (IFUBusRead still high) *** need to wait? else NextBusState = IDLE; // if (IFUBusRead still high) *** need to wait?
default: NextBusState = IDLE; default: NextBusState = IDLE;
endcase endcase
@ -129,7 +129,7 @@ module ahblite (
assign #1 HADDR = AccessAddress; assign #1 HADDR = AccessAddress;
assign ISize = 3'b010; // 32 bit instructions for now; later improve for filling cache with full width; ignored on reads anyway assign ISize = 3'b010; // 32 bit instructions for now; later improve for filling cache with full width; ignored on reads anyway
assign HSIZE = (GrantData) ? {1'b0, LSUBusSize[1:0]} : ISize; assign HSIZE = (GrantData) ? {1'b0, LSUBusSize[1:0]} : ISize;
assign HBURST = (GrantData) ? LSUBurstType : IFUBurstType; assign HBURST = (GrantData) ? LSUBurstType : IFUBurstType; // If doing memory accesses, use LSUburst, else use Instruction burst.
/* Cache burst read/writes case statement (hopefully) WRAPS only have access to 4 wraps. X changes position based on HSIZE. /* Cache burst read/writes case statement (hopefully) WRAPS only have access to 4 wraps. X changes position based on HSIZE.
000: Single (SINGLE) 000: Single (SINGLE)
@ -145,7 +145,7 @@ module ahblite (
assign HPROT = 4'b0011; // not used; see Section 3.7 assign HPROT = 4'b0011; // not used; see Section 3.7
assign HTRANS = (NextBusState != IDLE) ? 2'b10 : 2'b00; // NONSEQ if reading or writing, IDLE otherwise assign HTRANS = [SIGNAL TO SET SEQ] ? 2'b11 : (NextBusState != IDLE) ? 2'b10 : 2'b00; // SEQ if not first read or write, NONSEQ if first read or write, IDLE otherwise
assign HMASTLOCK = 0; // no locking supported assign HMASTLOCK = 0; // no locking supported
assign HWRITE = NextBusState == MEMWRITE; assign HWRITE = NextBusState == MEMWRITE;
// delay write data by one cycle for // delay write data by one cycle for
@ -161,7 +161,7 @@ module ahblite (
assign IFUBusHRDATA = HRDATA; assign IFUBusHRDATA = HRDATA;
assign LSUBusHRDATA = HRDATA; assign LSUBusHRDATA = HRDATA;
assign IFUBusAck = (BusState == INSTRREAD) & (NextBusState != INSTRREAD); assign IFUBusAck = HREADY & (BusState == INSTRREAD);
assign LSUBusAck = (BusState == MEMREAD) & (NextBusState != MEMREAD) | (BusState == MEMWRITE) & (NextBusState != MEMWRITE); assign LSUBusAck = HREADY & ((BusState == MEMREAD) | (BusState == MEMWRITE));
endmodule endmodule

4
pipelined/src/lsu/busfsm.sv
View File

@ -132,8 +132,8 @@ module busfsm #(parameter integer WordCountThreshold,
endcase // This block might be better in the FSM. WordCountThreshold is WordsPerLine endcase // This block might be better in the FSM. WordCountThreshold is WordsPerLine
end end
assign LSUBurstType = (UnCachedAccess) ? LocalBurstType : '0; // Don't want to use burst when doing an Uncached Access assign LSUBurstType = (UnCachedAccess) ? 3'b0 : LocalBurstType ; // Don't want to use burst when doing an Uncached Access
assign LSUBurstDone = WordCountFlag; assign LSUBurstDone = (UnCachedAccess) ? LSUBusAck : WordCountFlag & LSUBusAck;
assign CntReset = BusCurrState == STATE_BUS_READY; assign CntReset = BusCurrState == STATE_BUS_READY;
assign BusStall = (BusCurrState == STATE_BUS_READY & ~IgnoreRequest & ((UnCachedAccess & (|LSURWM)) | DCacheFetchLine | DCacheWriteLine)) | assign BusStall = (BusCurrState == STATE_BUS_READY & ~IgnoreRequest & ((UnCachedAccess & (|LSURWM)) | DCacheFetchLine | DCacheWriteLine)) |