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Added look-ahead write interface

This commit is contained in:
Clifford Wolf 2015-06-07 12:11:20 +02:00
parent e84f044bc5
commit bbbcea2faa
3 changed files with 73 additions and 58 deletions
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23
dhrystone/testbench.v
View File

@ -19,8 +19,12 @@ module testbench;
wire [31:0] mem_wdata;
wire [3:0] mem_wstrb;
reg [31:0] mem_rdata;
wire mem_la_read;
wire mem_la_write;
wire [31:0] mem_la_addr;
wire [31:0] mem_la_wdata;
wire [3:0] mem_la_wstrb;
picorv32 uut (
.clk (clk ),
@ -34,7 +38,10 @@ module testbench;
.mem_wstrb (mem_wstrb ),
.mem_rdata (mem_rdata ),
.mem_la_read (mem_la_read ),
.mem_la_addr(mem_la_addr)
.mem_la_write(mem_la_write),
.mem_la_addr (mem_la_addr ),
.mem_la_wdata(mem_la_wdata),
.mem_la_wstrb(mem_la_wstrb)
);
reg [31:0] memory [0:64*1024/4-1];
@ -45,19 +52,19 @@ module testbench;
always @(posedge clk) begin
if (mem_la_read)
mem_rdata <= memory[mem_la_addr >> 2];
if (mem_valid) begin
case (mem_addr)
if (mem_la_write) begin
case (mem_la_addr)
32'h1000_0000: begin
`ifndef TIMING
$write("%c", mem_wdata);
$write("%c", mem_la_wdata);
$fflush();
`endif
end
default: begin
if (mem_wstrb[0]) memory[mem_addr >> 2][ 7: 0] <= mem_wdata[ 7: 0];
if (mem_wstrb[1]) memory[mem_addr >> 2][15: 8] <= mem_wdata[15: 8];
if (mem_wstrb[2]) memory[mem_addr >> 2][23:16] <= mem_wdata[23:16];
if (mem_wstrb[3]) memory[mem_addr >> 2][31:24] <= mem_wdata[31:24];
if (mem_la_wstrb[0]) memory[mem_la_addr >> 2][ 7: 0] <= mem_la_wdata[ 7: 0];
if (mem_la_wstrb[1]) memory[mem_la_addr >> 2][15: 8] <= mem_la_wdata[15: 8];
if (mem_la_wstrb[2]) memory[mem_la_addr >> 2][23:16] <= mem_la_wdata[23:16];
if (mem_la_wstrb[3]) memory[mem_la_addr >> 2][31:24] <= mem_la_wdata[31:24];
end
endcase
end

32
picorv32.v
View File

@ -43,7 +43,10 @@ module picorv32 #(
// look-ahead interface
output mem_la_read,
output [31:0] mem_la_addr
output mem_la_write,
output [31:0] mem_la_addr,
output reg [31:0] mem_la_wdata,
output reg [ 3:0] mem_la_wstrb
);
localparam integer regfile_size = ENABLE_REGS_16_31 ? 32 : 16;
localparam integer regindex_bits = ENABLE_REGS_16_31 ? 5 : 4;
@ -69,22 +72,29 @@ module picorv32 #(
wire mem_done = mem_ready && ((mem_state[0] && (mem_do_rinst || mem_do_rdata)) || mem_state == 2);
assign mem_la_write = resetn && !mem_state && mem_do_wdata;
assign mem_la_read = resetn && !mem_state && (mem_do_rinst || mem_do_prefetch || mem_do_rdata);
assign mem_la_addr = mem_do_prefetch || mem_do_rinst ? next_pc : {reg_op1[31:2], 2'b00};
assign mem_la_addr = (mem_do_prefetch || mem_do_rinst) ? next_pc : {reg_op1[31:2], 2'b00};
always @* begin
(* full_case *)
case (mem_wordsize)
0: begin
mem_la_wdata = reg_op2;
mem_la_wstrb = 4'b1111;
mem_buffer = mem_rdata;
end
1: begin
mem_la_wdata = {2{reg_op2[15:0]}};
mem_la_wstrb = reg_op1[1] ? 4'b1100 : 4'b0011;
case (reg_op1[1])
1'b0: mem_buffer = mem_rdata[15: 0];
1'b1: mem_buffer = mem_rdata[31:16];
endcase
end
2: begin
mem_la_wdata = {4{reg_op2[7:0]}};
mem_la_wstrb = 4'b0001 << reg_op1[1:0];
case (reg_op1[1:0])
2'b00: mem_buffer = mem_rdata[ 7: 0];
2'b01: mem_buffer = mem_rdata[15: 8];
@ -102,6 +112,8 @@ module picorv32 #(
end else case (mem_state)
0: begin
mem_addr <= mem_la_addr;
mem_wdata <= mem_la_wdata;
mem_wstrb <= mem_la_wstrb;
if (mem_do_prefetch || mem_do_rinst || mem_do_rdata) begin
mem_valid <= 1;
mem_instr <= mem_do_prefetch || mem_do_rinst;
@ -110,23 +122,7 @@ module picorv32 #(
end
if (mem_do_wdata) begin
mem_valid <= 1;
mem_addr <= {reg_op1[31:2], 2'b00};
mem_instr <= 0;
(* full_case *)
case (mem_wordsize)
0: begin
mem_wdata <= reg_op2;
mem_wstrb <= 4'b1111;
end
1: begin
mem_wdata <= {2{reg_op2[15:0]}};
mem_wstrb <= reg_op1[1] ? 4'b1100 : 4'b0011;
end
2: begin
mem_wdata <= {4{reg_op2[7:0]}};
mem_wstrb <= 4'b0001 << reg_op1[1:0];
end
endcase
mem_state <= 2;
end
end

30
scripts/synth_vivado_soc.v
View File

@ -5,7 +5,7 @@ module test_soc (
input resetn,
output trap,
output [7:0] out_byte,
output out_byte_en,
output reg out_byte_en,
output monitor_valid,
output [31:0] monitor_addr,
@ -20,8 +20,12 @@ module test_soc (
wire [31:0] mem_wdata;
wire [3:0] mem_wstrb;
reg [31:0] mem_rdata;
wire mem_la_read;
wire mem_la_write;
wire [31:0] mem_la_addr;
wire [31:0] mem_la_wdata;
wire [3:0] mem_la_wstrb;
picorv32 uut (
.clk (clk ),
@ -35,7 +39,10 @@ module test_soc (
.mem_wstrb (mem_wstrb ),
.mem_rdata (mem_rdata ),
.mem_la_read (mem_la_read ),
.mem_la_addr(mem_la_addr)
.mem_la_write(mem_la_write),
.mem_la_addr (mem_la_addr ),
.mem_la_wdata(mem_la_wdata),
.mem_la_wstrb(mem_la_wstrb)
);
assign monitor_valid = mem_valid;
@ -46,17 +53,22 @@ module test_soc (
initial $readmemh("../firmware/firmware.hex", memory);
assign mem_ready = 1;
assign out_byte = mem_wdata[7:0];
assign out_byte_en = mem_addr == 32'h1000_0000;
always @(posedge clk) begin
out_byte_en <= 0;
if (mem_la_read)
mem_rdata <= memory[mem_la_addr >> 2];
if (mem_valid && (mem_addr >> 2) < MEM_SIZE) begin
if (mem_wstrb[0]) memory[mem_addr >> 2][ 7: 0] <= mem_wdata[ 7: 0];
if (mem_wstrb[1]) memory[mem_addr >> 2][15: 8] <= mem_wdata[15: 8];
if (mem_wstrb[2]) memory[mem_addr >> 2][23:16] <= mem_wdata[23:16];
if (mem_wstrb[3]) memory[mem_addr >> 2][31:24] <= mem_wdata[31:24];
else
if (mem_la_write && (mem_la_addr >> 2) < MEM_SIZE) begin
if (mem_la_wstrb[0]) memory[mem_la_addr >> 2][ 7: 0] <= mem_la_wdata[ 7: 0];
if (mem_la_wstrb[1]) memory[mem_la_addr >> 2][15: 8] <= mem_la_wdata[15: 8];
if (mem_la_wstrb[2]) memory[mem_la_addr >> 2][23:16] <= mem_la_wdata[23:16];
if (mem_la_wstrb[3]) memory[mem_la_addr >> 2][31:24] <= mem_la_wdata[31:24];
end
else
if (mem_la_write && mem_la_addr == 32'h1000_0000) begin
out_byte_en <= 1;
end
end
endmodule