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Added signals to change HTRANS to the correct signal based on schematic as well as a way to tell if we are not on the first access

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slmnemo 2022-05-31 16:33:05 -07:00
parent 2b80788235
commit 56121b3587
1 changed files with 6 additions and 4 deletions
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10
pipelined/src/ebu/ahblite.sv
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@ -75,10 +75,11 @@ module ahblite (
(* mark_debug = "true" *) output logic HWRITED
);
typedef enum logic [1:0] {IDLE, MEMREAD, MEMWRITE, INSTRREAD} statetype;
typedef enum logic [2:0] {IDLE, MEMREAD, MEMREADNEXT, MEMWRITE, MEMWRITENEXT, INSTRREAD, INSTRREADNEXT} statetype;
statetype BusState, NextBusState;
logic GrantData;
logic SubsequentAccess;
logic [31:0] AccessAddress;
logic [2:0] ISize;
@ -135,6 +136,7 @@ module ahblite (
assign #1 GrantData = (NextBusState == MEMREAD) | (NextBusState == MEMWRITE) |
(NextBusState == MEMREADNEXT) | (NextBusState == MEMWRITENEXT);
assign #1 AccessAddress = (GrantData) ? LSUBusAdr[31:0] : IFUBusAdr[31:0];
assign #1 SubsequentAccess = (GrantData) ? |(AccessAddress[$clog2(`XLEN):0]) : |(AccessAddress[5:0]);
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 HSIZE = (GrantData) ? {1'b0, LSUBusSize[1:0]} : ISize;
@ -154,7 +156,7 @@ module ahblite (
assign HPROT = 4'b0011; // not used; see Section 3.7
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 HTRANS = SubsequentAccess ? 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 HWRITE = (NextBusState == MEMWRITE) | (NextBusState == MEMWRITENEXT);
// delay write data by one cycle for
@ -170,7 +172,7 @@ module ahblite (
assign IFUBusHRDATA = HRDATA;
assign LSUBusHRDATA = HRDATA;
assign IFUBusAck = (BusState == INSTRREAD) & (NextBusState != INSTRREAD); // *** these are wrong.
assign LSUBusAck = (BusState == MEMREAD) & (NextBusState != MEMREAD) | (BusState == MEMWRITE) & (NextBusState != MEMWRITE); // *** these are wrong.
assign IFUBusAck = (BusState == INSTRREADNEXT);
assign LSUBusAck = (BusState == MEMREADNEXT) | (BusState == MEMWRITENEXT);
endmodule