🎨 Code cleanup

This commit is contained in:
Florian Zaruba 2017-05-13 12:15:23 +02:00
parent da521c9f26
commit dc823ae54a
3 changed files with 150 additions and 199 deletions

View file

@ -23,219 +23,178 @@
import ariane_pkg::*;
// input port: send address one cycle before the data
// clear_i clears the FIFO for the following cycle. in_addr_i can be sent in
// this cycle already
// clear_i clears the FIFO for the following cycle.
module fetch_fifo
(
input logic clk,
input logic rst_n,
// control signals
input logic clear_i, // clears the contents of the fifo
// input port
input logic [63:0] in_addr_i,
input logic [31:0] in_rdata_i,
input logic in_valid_i,
output logic in_ready_o,
// output port
output logic [63:0] out_addr_o,
output logic [31:0] out_rdata_o,
output logic out_valid_o,
input logic out_ready_i,
input logic out_ready_i
);
output logic out_valid_stored_o // same as out_valid_o, except that if something is incoming now it is not
// included. This signal is available immediately as it comes directly out of FFs
);
localparam DEPTH = 4; // must be 3 or greater
/* verilator lint_off LITENDIAN */
// index 0 is used for output
logic [0:DEPTH-1] [63:0] addr_n, addr_int, addr_Q;
logic [0:DEPTH-1] [31:0] rdata_n, rdata_int, rdata_Q;
logic [0:DEPTH-1] valid_n, valid_int, valid_Q;
localparam DEPTH = 4; // must be 3 or greater
/* verilator lint_off LITENDIAN */
// index 0 is used for output
logic [0:DEPTH-1] [63:0] addr_n, addr_int, addr_Q;
logic [0:DEPTH-1] [31:0] rdata_n, rdata_int, rdata_Q;
logic [0:DEPTH-1] valid_n, valid_int, valid_Q;
logic [63:0] addr_next;
logic [31:0] rdata, rdata_unaligned;
logic valid, valid_unaligned;
logic [63:0] addr_next;
logic [31:0] rdata, rdata_unaligned;
logic valid, valid_unaligned;
logic aligned_is_compressed, unaligned_is_compressed;
logic aligned_is_compressed_st, unaligned_is_compressed_st;
/* lint_on */
logic aligned_is_compressed, unaligned_is_compressed;
logic aligned_is_compressed_st, unaligned_is_compressed_st;
/* lint_on */
//----------------------------------------------------------------------------
// output port
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
// output port
//----------------------------------------------------------------------------
assign rdata = (valid_Q[0]) ? rdata_Q[0] : in_rdata_i;
assign valid = valid_Q[0] || in_valid_i;
assign rdata_unaligned = (valid_Q[1]) ? {rdata_Q[1][15:0], rdata[31:16]} : {in_rdata_i[15:0], rdata[31:16]};
// it is implied that rdata_valid_Q[0] is set
assign valid_unaligned = (valid_Q[1] || (valid_Q[0] && in_valid_i));
assign rdata = (valid_Q[0]) ? rdata_Q[0] : in_rdata_i;
assign valid = valid_Q[0] || in_valid_i;
assign unaligned_is_compressed = rdata[17:16] != 2'b11;
assign aligned_is_compressed = rdata[1:0] != 2'b11;
assign unaligned_is_compressed_st = rdata_Q[0][17:16] != 2'b11;
assign aligned_is_compressed_st = rdata_Q[0][1:0] != 2'b11;
assign rdata_unaligned = (valid_Q[1]) ? {rdata_Q[1][15:0], rdata[31:16]} : {in_rdata_i[15:0], rdata[31:16]};
// it is implied that rdata_valid_Q[0] is set
assign valid_unaligned = (valid_Q[1] || (valid_Q[0] && in_valid_i));
//----------------------------------------------------------------------------
// instruction aligner (if unaligned)
//----------------------------------------------------------------------------
always_comb begin
// serve the aligned case even though the output address is unaligned when
// the next instruction will be from a hardware loop target
// in this case the current instruction is already prealigned in element 0
if (out_addr_o[1]) begin
// unaligned case
out_rdata_o = rdata_unaligned;
assign unaligned_is_compressed = rdata[17:16] != 2'b11;
assign aligned_is_compressed = rdata[1:0] != 2'b11;
assign unaligned_is_compressed_st = rdata_Q[0][17:16] != 2'b11;
assign aligned_is_compressed_st = rdata_Q[0][1:0] != 2'b11;
//----------------------------------------------------------------------------
// instruction aligner (if unaligned)
//----------------------------------------------------------------------------
always_comb
begin
// serve the aligned case even though the output address is unaligned when
// the next instruction will be from a hardware loop target
// in this case the current instruction is already prealigned in element 0
if (out_addr_o[1]) begin
// unaligned case
out_rdata_o = rdata_unaligned;
if (unaligned_is_compressed)
if (unaligned_is_compressed)
out_valid_o = valid;
else
out_valid_o = valid_unaligned;
end else begin
// aligned case
out_rdata_o = rdata;
out_valid_o = valid;
else
out_valid_o = valid_unaligned;
end else begin
// aligned case
out_rdata_o = rdata;
out_valid_o = valid;
end
end
assign out_addr_o = (valid_Q[0]) ? addr_Q[0] : in_addr_i;
// this valid signal must not depend on signals from outside!
always_comb
begin
out_valid_stored_o = 1'b1;
if (out_addr_o[1]) begin
if (unaligned_is_compressed_st)
out_valid_stored_o = 1'b1;
else
out_valid_stored_o = valid_Q[1];
end else begin
out_valid_stored_o = valid_Q[0];
end
end
//----------------------------------------------------------------------------
// input port
//----------------------------------------------------------------------------
// we accept data as long as our fifo is not full
// we don't care about clear here as the data will be received one cycle
// later anyway
assign in_ready_o = ~valid_Q[DEPTH-2];
//----------------------------------------------------------------------------
// FIFO management
//----------------------------------------------------------------------------
int j;
always_comb
begin
addr_int = addr_Q;
rdata_int = rdata_Q;
valid_int = valid_Q;
if (in_valid_i) begin
for(j = 0; j < DEPTH; j++) begin
if (~valid_Q[j]) begin
addr_int[j] = in_addr_i;
rdata_int[j] = in_rdata_i;
valid_int[j] = 1'b1;
break;
end
end
end
end
assign addr_next = {addr_int[0][63:2], 2'b00} + 64'h4;
assign out_addr_o = (valid_Q[0]) ? addr_Q[0] : in_addr_i;
// move everything by one step
always_comb
begin
addr_n = addr_int;
rdata_n = rdata_int;
valid_n = valid_int;
//----------------------------------------------------------------------------
// input port
//----------------------------------------------------------------------------
// we accept data as long as our fifo is not full
// we don't care about clear here as the data will be received one cycle
// later anyway
assign in_ready_o = ~valid_Q[DEPTH-2];
if (out_ready_i && out_valid_o) begin
begin
if (addr_int[0][1]) begin
// unaligned case
if (unaligned_is_compressed) begin
addr_n[0] = {addr_next[63:2], 2'b00};
end else begin
addr_n[0] = {addr_next[63:2], 2'b10};
end
//----------------------------------------------------------------------------
// FIFO management
//----------------------------------------------------------------------------
always_comb begin
addr_int = addr_Q;
rdata_int = rdata_Q;
valid_int = valid_Q;
for (int i = 0; i < DEPTH - 1; i++)
begin
rdata_n[i] = rdata_int[i + 1];
end
rdata_n[DEPTH - 1] = 32'b0;
if (in_valid_i) begin
for (int j = 0; j < DEPTH; j++) begin
if (~valid_Q[j]) begin
addr_int[j] = in_addr_i;
rdata_int[j] = in_rdata_i;
valid_int[j] = 1'b1;
break;
end
end
end
end
valid_n = {valid_int[1:DEPTH-1], 1'b0};
assign addr_next = {addr_int[0][63:2], 2'b00} + 64'h4;
// move everything by one step
always_comb begin
addr_n = addr_int;
rdata_n = rdata_int;
valid_n = valid_int;
if (out_ready_i && out_valid_o) begin
if (addr_int[0][1]) begin
// unaligned case
if (unaligned_is_compressed) begin
addr_n[0] = {addr_next[63:2], 2'b00};
end else begin
addr_n[0] = {addr_next[63:2], 2'b10};
end
// shift everything on ene step
for (int i = 0; i < DEPTH - 1; i++)
rdata_n[i] = rdata_int[i + 1];
rdata_n[DEPTH - 1] = 32'b0;
valid_n = {valid_int[1:DEPTH-1], 1'b0};
end else begin
if (aligned_is_compressed) begin
// just increase address, do not move to next entry in FIFO
addr_n[0] = {addr_int[0][63:2], 2'b10};
end else begin
// move to next entry in FIFO
addr_n[0] = {addr_next[63:2], 2'b00};
// shift entry
for (int i = 0; i < DEPTH - 1; i++)
rdata_n[i] = rdata_int[i + 1];
rdata_n[DEPTH - 1] = 32'b0;
valid_n = {valid_int[1:DEPTH-1], 1'b0};
end
end
end
// on a clear signal from outside we invalidate the content of the FIFO
// completely and start from an empty state
if (clear_i)
valid_n = '0;
end
//----------------------------------------------------------------------------
// registers
//----------------------------------------------------------------------------
always_ff @(posedge clk, negedge rst_n) begin
if(rst_n == 1'b0) begin
addr_Q <= '{default: '0};
rdata_Q <= '{default: '0};
valid_Q <= '0;
end else begin
if (aligned_is_compressed) begin
// just increase address, do not move to next entry in FIFO
addr_n[0] = {addr_int[0][63:2], 2'b10};
end else begin
// move to next entry in FIFO
addr_n[0] = {addr_next[63:2], 2'b00};
for (int i = 0; i < DEPTH - 1; i++) begin
rdata_n[i] = rdata_int[i + 1];
end
rdata_n[DEPTH - 1] = 32'b0;
valid_n = {valid_int[1:DEPTH-1], 1'b0};
addr_Q <= addr_n;
rdata_Q <= rdata_n;
valid_Q <= valid_n;
end
end
end
end
end
//----------------------------------------------------------------------------
// registers
//----------------------------------------------------------------------------
always_ff @(posedge clk, negedge rst_n)
begin
if(rst_n == 1'b0)
begin
addr_Q <= '{default: '0};
rdata_Q <= '{default: '0};
valid_Q <= '0;
end
else
begin
// on a clear signal from outside we invalidate the content of the FIFO
// completely and start from an empty state
if (clear_i) begin
valid_Q <= '0;
end else begin
addr_Q <= addr_n;
rdata_Q <= rdata_n;
valid_Q <= valid_n;
end
end
end
//----------------------------------------------------------------------------
// Assertions
//----------------------------------------------------------------------------
`ifndef SYNTHESIS
`ifndef VERILATOR
assert property (
@(posedge clk) (in_valid_i) |-> ((valid_Q[DEPTH-1] == 1'b0) || (clear_i == 1'b1)) );
`endif
`endif
//----------------------------------------------------------------------------
// Assertions
//----------------------------------------------------------------------------
`ifndef SYNTHESIS
`ifndef VERILATOR
assert property (
@(posedge clk) (in_valid_i) |-> ((valid_Q[DEPTH-1] == 1'b0) || (clear_i == 1'b1)) );
`endif
`endif
endmodule

View file

@ -58,9 +58,6 @@ module prefetch_buffer
logic fifo_ready;
logic fifo_clear;
logic valid_stored;
//---------------------------------
// Prefetch buffer status
//---------------------------------
@ -71,26 +68,23 @@ module prefetch_buffer
// Fetch FIFO
// consumes addresses and rdata
//---------------------------------
fetch_fifo fifo_i
(
.clk ( clk ),
.rst_n ( rst_n ),
fetch_fifo fifo_i (
.clk ( clk ),
.rst_n ( rst_n ),
.clear_i ( fifo_clear ),
.clear_i ( fifo_clear ),
.in_addr_i ( instr_addr_q ),
.in_rdata_i ( instr_rdata_i ),
.in_valid_i ( fifo_valid ),
.in_ready_o ( fifo_ready ),
.in_addr_i ( instr_addr_q ),
.in_rdata_i ( instr_rdata_i ),
.in_valid_i ( fifo_valid ),
.in_ready_o ( fifo_ready ),
.out_valid_o ( valid_o ),
.out_ready_i ( ready_i ),
.out_rdata_o ( rdata_o ),
.out_addr_o ( addr_o ),
.out_valid_stored_o ( valid_stored )
);
.out_valid_o ( valid_o ),
.out_ready_i ( ready_i ),
.out_rdata_o ( rdata_o ),
.out_addr_o ( addr_o )
);
//---------------

View file

@ -1,6 +1,4 @@
.text
nop
nop
nop
addi x1, x0, 1
addi x2, x0, 1