Files
vortex/hw/rtl/VX_lsu_unit.v
2020-08-14 21:50:14 -07:00

228 lines
9.2 KiB
Verilog

`include "VX_define.vh"
module VX_lsu_unit #(
parameter CORE_ID = 0
) (
`SCOPE_SIGNALS_LSU_IO
input wire clk,
input wire reset,
// Dcache interface
VX_cache_core_req_if dcache_req_if,
VX_cache_core_rsp_if dcache_rsp_if,
// inputs
VX_lsu_req_if lsu_req_if,
// outputs
VX_exu_to_cmt_if lsu_commit_if
);
wire valid_in;
wire ready_in;
wire [`NUM_THREADS-1:0] req_thread_mask;
wire req_rw;
wire [`NUM_THREADS-1:0][29:0] req_addr;
wire [`NUM_THREADS-1:0][1:0] req_offset;
wire [`NUM_THREADS-1:0][3:0] req_byteen;
wire [`NUM_THREADS-1:0][31:0] req_data;
wire [1:0] req_sext;
wire [`NR_BITS-1:0] req_rd;
wire [`NW_BITS-1:0] req_wid;
wire [`ISTAG_BITS-1:0] req_issue_tag;
wire req_wb;
wire [31:0] req_pc;
wire [`NUM_THREADS-1:0][31:0] full_address;
for (genvar i = 0; i < `NUM_THREADS; i++) begin
assign full_address[i] = lsu_req_if.base_addr[i] + lsu_req_if.offset;
end
reg [1:0] mem_req_sext;
always @(*) begin
case (lsu_req_if.byteen)
`BYTEEN_SB: mem_req_sext = 2'h1;
`BYTEEN_SH: mem_req_sext = 2'h2;
default: mem_req_sext = 2'h0;
endcase
end
wire [`NUM_THREADS-1:0][29:0] mem_req_addr;
wire [`NUM_THREADS-1:0][1:0] mem_req_offset;
wire [`NUM_THREADS-1:0][3:0] mem_req_byteen;
wire [`NUM_THREADS-1:0][31:0] mem_req_data;
reg [3:0] wmask;
always @(*) begin
case (`BYTEEN_TYPE(lsu_req_if.byteen))
0: wmask = 4'b0001;
1: wmask = 4'b0011;
default: wmask = 4'b1111;
endcase
end
for (genvar i = 0; i < `NUM_THREADS; i++) begin
assign mem_req_addr[i] = full_address[i][31:2];
assign mem_req_offset[i] = full_address[i][1:0];
assign mem_req_byteen[i] = wmask << full_address[i][1:0];
assign mem_req_data[i] = lsu_req_if.store_data[i] << {mem_req_offset[i], 3'b0};
end
`IGNORE_WARNINGS_BEGIN
wire [`NUM_THREADS-1:0][31:0] req_address;
`IGNORE_WARNINGS_END
// use a skid buffer because the dcache's ready signal is combinational
// use buffer size of two for stall-free execution
VX_elastic_buffer #(
.DATAW (`NW_BITS + `NUM_THREADS + `ISTAG_BITS + (`NUM_THREADS * 32) + 2 + 1 + (`NUM_THREADS * (30 + 2 + 4 + 32)) + `NR_BITS + 1 + 32),
.SIZE (2)
) input_buffer (
.clk (clk),
.reset (reset),
.valid_in (lsu_req_if.valid),
.ready_in (lsu_req_if.ready),
.data_in ({lsu_req_if.wid, lsu_req_if.thread_mask, lsu_req_if.issue_tag, full_address, mem_req_sext, lsu_req_if.rw, mem_req_addr, mem_req_offset, mem_req_byteen, mem_req_data, lsu_req_if.rd, lsu_req_if.wb, lsu_req_if.curr_PC}),
.data_out ({req_wid, req_thread_mask, req_issue_tag, req_address, req_sext, req_rw, req_addr, req_offset, req_byteen, req_data, req_rd, req_wb, req_pc}),
.ready_out (ready_in),
.valid_out (valid_in)
);
reg [`ISSUEQ_SIZE-1:0][`NUM_THREADS-1:0] mem_rsp_mask_buf;
reg [`ISSUEQ_SIZE-1:0][`NUM_THREADS-1:0][31:0] mem_rsp_data_prev_buf;
reg [`NUM_THREADS-1:0][1:0] mem_rsp_offset_buf [`ISSUEQ_SIZE-1:0];
reg [1:0] mem_rsp_sext_buf [`ISSUEQ_SIZE-1:0];
reg [`NW_BITS-1:0] mem_rsp_wid_buf [`ISSUEQ_SIZE-1:0];
reg [31:0] mem_rsp_curr_PC_buf [`ISSUEQ_SIZE-1:0];
reg [`NR_BITS-1:0] mem_rsp_rd_buf [`ISSUEQ_SIZE-1:0];
reg [`NUM_THREADS-1:0][31:0] mem_rsp_data_curr;
wire [`ISTAG_BITS-1:0] rsp_issue_tag = dcache_rsp_if.tag[0][`ISTAG_BITS-1:0];
wire [`NUM_THREADS-1:0] mem_rsp_mask = mem_rsp_mask_buf [rsp_issue_tag];
wire [`NUM_THREADS-1:0][1:0] mem_rsp_offset = mem_rsp_offset_buf [rsp_issue_tag];
wire [1:0] mem_rsp_sext = mem_rsp_sext_buf [rsp_issue_tag];
wire [`NUM_THREADS-1:0][31:0] mem_rsp_data_prev= mem_rsp_data_prev_buf [rsp_issue_tag];
wire [`NW_BITS-1:0] mem_rsp_wid = mem_rsp_wid_buf [rsp_issue_tag];
wire [31:0] mem_rsp_curr_PC = mem_rsp_curr_PC_buf [rsp_issue_tag];
wire [`NR_BITS-1:0] mem_rsp_rd = mem_rsp_rd_buf [rsp_issue_tag];
wire dcache_req_fire = (| dcache_req_if.valid) && dcache_req_if.ready;
wire dcache_rsp_fire = (| dcache_rsp_if.valid) && dcache_rsp_if.ready;
wire [`NUM_THREADS-1:0] mem_rsp_mask_n = mem_rsp_mask & ~dcache_rsp_if.valid;
always @(posedge clk) begin
if (dcache_req_fire && (0 == req_rw)) begin
mem_rsp_mask_buf [req_issue_tag] <= req_thread_mask;
mem_rsp_data_prev_buf [req_issue_tag] <= 0;
end
if (dcache_rsp_fire) begin
mem_rsp_mask_buf [rsp_issue_tag] <= mem_rsp_mask_n;
mem_rsp_data_prev_buf [rsp_issue_tag] <= mem_rsp_data_curr | mem_rsp_data_prev;
end
end
always @(posedge clk) begin
if (dcache_req_fire && (0 == req_rw)) begin
mem_rsp_offset_buf [req_issue_tag] <= req_offset;
mem_rsp_sext_buf [req_issue_tag] <= req_sext;
mem_rsp_wid_buf [req_issue_tag] <= req_wid;
mem_rsp_curr_PC_buf [req_issue_tag] <= req_pc;
mem_rsp_rd_buf [req_issue_tag] <= req_rd;
end
end
wire stall_in;
// Core Request
assign dcache_req_if.valid = {`NUM_THREADS{valid_in && ~stall_in}} & req_thread_mask;
assign dcache_req_if.rw = {`NUM_THREADS{req_rw}};
assign dcache_req_if.byteen = req_byteen;
assign dcache_req_if.addr = req_addr;
assign dcache_req_if.data = req_data;
assign ready_in = dcache_req_if.ready && ~stall_in;
`ifdef DBG_CORE_REQ_INFO
assign dcache_req_if.tag = {req_pc, req_wb, req_rd, req_wid, req_issue_tag};
`else
assign dcache_req_if.tag = req_issue_tag;
`endif
// Core Response
for (genvar i = 0; i < `NUM_THREADS; i++) begin
wire [31:0] rsp_data_shifted = dcache_rsp_if.data[i] >> {mem_rsp_offset[i], 3'b0};
always @(*) begin
case (mem_rsp_sext)
1: mem_rsp_data_curr[i] = {{24{rsp_data_shifted[7]}}, rsp_data_shifted[7:0]};
2: mem_rsp_data_curr[i] = {{16{rsp_data_shifted[15]}}, rsp_data_shifted[15:0]};
default: mem_rsp_data_curr[i] = rsp_data_shifted;
endcase
end
end
reg is_load_rsp;
reg [`NUM_THREADS-1:0][31:0] load_data;
reg [`ISTAG_BITS-1:0] rsp_issue_tag_r;
always @(posedge clk) begin
if (reset) begin
is_load_rsp <= 0;
end else begin
is_load_rsp <= dcache_rsp_fire && (0 == mem_rsp_mask_n);
load_data <= mem_rsp_data_curr | mem_rsp_data_prev;
rsp_issue_tag_r <= rsp_issue_tag;
end
end
wire is_store_req = dcache_req_fire && req_rw;
assign stall_in = is_load_rsp && valid_in && req_rw; // LOAD has priority
assign lsu_commit_if.valid = is_load_rsp || is_store_req;
assign lsu_commit_if.issue_tag = is_load_rsp ? rsp_issue_tag_r : req_issue_tag;
assign lsu_commit_if.data = load_data;
// Can accept new cache response?
assign dcache_rsp_if.ready = 1'b1;
// scope registration
`SCOPE_ASSIGN (scope_dcache_req_valid, dcache_req_if.valid);
`SCOPE_ASSIGN (scope_dcache_req_addr, req_address);
`SCOPE_ASSIGN (scope_dcache_req_rw, dcache_req_if.rw );
`SCOPE_ASSIGN (scope_dcache_req_byteen,dcache_req_if.byteen);
`SCOPE_ASSIGN (scope_dcache_req_data, dcache_req_if.data);
`SCOPE_ASSIGN (scope_dcache_req_tag, dcache_req_if.tag);
`SCOPE_ASSIGN (scope_dcache_req_ready, dcache_req_if.ready);
`SCOPE_ASSIGN (scope_dcache_req_wid, req_wid);
`SCOPE_ASSIGN (scope_dcache_req_curr_PC, req_pc);
`SCOPE_ASSIGN (scope_dcache_rsp_valid, dcache_rsp_if.valid);
`SCOPE_ASSIGN (scope_dcache_rsp_data, dcache_rsp_if.data);
`SCOPE_ASSIGN (scope_dcache_rsp_tag, dcache_rsp_if.tag);
`SCOPE_ASSIGN (scope_dcache_rsp_ready, dcache_rsp_if.ready);
`UNUSED_VAR (mem_rsp_wid)
`UNUSED_VAR (mem_rsp_curr_PC)
`UNUSED_VAR (mem_rsp_rd)
`UNUSED_VAR (req_wb)
`ifdef DBG_PRINT_CORE_DCACHE
always @(posedge clk) begin
if ((| dcache_req_if.valid) && dcache_req_if.ready) begin
$display("%t: D$%0d req: wid=%0d, PC=%0h, tmask=%b, addr=%0h, tag=%0h, rd=%0d, rw=%0b, byteen=%0h, data=%0h",
$time, CORE_ID, req_wid, req_pc, dcache_req_if.valid, req_address, dcache_req_if.tag, req_rd, dcache_req_if.rw, dcache_req_if.byteen, dcache_req_if.data);
end
if ((| dcache_rsp_if.valid) && dcache_rsp_if.ready) begin
$display("%t: D$%0d rsp: valid=%b, wid=%0d, PC=%0h, tag=%0h, rd=%0d, data=%0h",
$time, CORE_ID, dcache_rsp_if.valid, mem_rsp_wid, mem_rsp_curr_PC, dcache_rsp_if.tag, mem_rsp_rd, dcache_rsp_if.data);
end
end
`endif
endmodule