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Simplify instr core interface

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This commit is contained in:
Andreas Traber 2015-09-04 15:52:35 +02:00
parent adb40aef43
commit 4f06b67e65
2 changed files with 29 additions and 45 deletions
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4
controller.sv
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@ -925,7 +925,7 @@ module controller
// note: this is done intentionally before checking RVC decoding, to
// suppress wrong (and annoying) messages during simulation
if (illegal_insn_o) begin
$warning("Illegal instruction (core %0d) at PC 0x%h:", $time, riscv_core.core_id_i);
$warning("%t: Illegal instruction (core %0d) at PC 0x%h:", $time, riscv_core.core_id_i);
//prettyPrintInstruction(instr_rdata_i, id_stage.current_pc_id_i);
end
end
@ -1152,6 +1152,7 @@ module controller
end
end
// flush the pipeline, insert NOP into EX stage
FLUSH_EX:
begin
halt_if = 1'b1;
@ -1161,6 +1162,7 @@ module controller
ctrl_fsm_ns = FLUSH_WB;
end
// flush the pipeline, insert NOP into EX and WB stage
FLUSH_WB:
begin
halt_if = 1'b1;

70
instr_core_interface.sv
View file

@ -42,7 +42,7 @@ module instr_core_interface
input logic [31:0] instr_rdata_i
);
enum logic [1:0] {IDLE, PENDING, WAIT_RVALID, WAIT_GNT } CS, NS;
enum logic [1:0] {IDLE, WAIT_RVALID, WAIT_GNT } CS, NS;
logic [31:0] rdata_Q;
@ -61,11 +61,8 @@ module instr_core_interface
begin
CS <= NS;
if (instr_req_o && instr_gnt_i)
addr_Q <= instr_addr_o;
if (wait_gnt)
addr_Q <= addr_i;
addr_Q <= instr_addr_o;
if (instr_rvalid_i)
rdata_Q <= instr_rdata_i;
@ -81,6 +78,7 @@ module instr_core_interface
rdata_o = instr_rdata_i;
instr_addr_o = addr_i;
wait_gnt = 1'b0;
NS = CS;
unique case(CS)
// default state, not waiting for requested data
@ -88,15 +86,16 @@ module instr_core_interface
begin
rdata_o = rdata_Q;
NS = IDLE;
instr_req_o = req_i;
instr_req_o = 1'b0;
if(req_i) begin
instr_req_o = 1'b1;
wait_gnt = 1'b1;
if(instr_gnt_i) //~> granted request
NS = PENDING;
NS = WAIT_RVALID;
else begin //~> got a request but no grant
NS = WAIT_GNT;
wait_gnt = 1'b1;
end
end
end // case: IDLE
@ -108,52 +107,35 @@ module instr_core_interface
instr_req_o = 1'b1;
if(instr_gnt_i)
NS = PENDING;
NS = WAIT_RVALID;
else
begin
NS = WAIT_GNT;
end
end // case: WAIT_GNT
// we got a grant, so now we wait for the rvalid
PENDING:
begin
if (instr_rvalid_i) begin
NS = IDLE;
instr_req_o = req_i;
if (req_i) begin
if (instr_gnt_i) begin
NS = PENDING;
end else begin
NS = WAIT_GNT;
wait_gnt = 1'b1;
end
end
end else begin
NS = WAIT_RVALID;
instr_req_o = 1'b0;
end
end // case: PENDING
// we wait for rvalid, after that we are ready to serve a new request
WAIT_RVALID :
begin
NS = WAIT_RVALID;
instr_req_o = 1'b0;
if (instr_rvalid_i) begin
NS = IDLE;
instr_req_o = req_i;
if (req_i) begin
// prepare for next request
instr_req_o = 1'b1;
if (req_i) begin
if (instr_gnt_i)
NS = PENDING;
else begin
NS = WAIT_GNT;
wait_gnt = 1'b1;
if (instr_rvalid_i) begin
wait_gnt = 1'b1;
if (instr_gnt_i) begin
NS = WAIT_RVALID;
end else begin
NS = WAIT_GNT;
end
end
end else begin
// just wait for rvalid and go back to IDLE, no new request
// requested
instr_req_o = 1'b0;
if (instr_rvalid_i) begin
NS = IDLE;
end
end
end // case: WAIT_RVALID