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[/] [openrisc/] [trunk/] [or1200/] [rtl/] [verilog/] [or1200_dc_fsm.v] - Rev 134
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////////////////////////////////////////////////////////////////////// //// //// //// OR1200's DC FSM //// //// //// //// This file is part of the OpenRISC 1200 project //// //// http://www.opencores.org/cores/or1k/ //// //// //// //// Description //// //// Data cache state machine //// //// //// //// To Do: //// //// - make it smaller and faster //// //// //// //// Author(s): //// //// - Damjan Lampret, lampret@opencores.org //// //// //// ////////////////////////////////////////////////////////////////////// //// //// //// Copyright (C) 2000 Authors and OPENCORES.ORG //// //// //// //// This source file may be used and distributed without //// //// restriction provided that this copyright statement is not //// //// removed from the file and that any derivative work contains //// //// the original copyright notice and the associated disclaimer. //// //// //// //// This source file is free software; you can redistribute it //// //// and/or modify it under the terms of the GNU Lesser General //// //// Public License as published by the Free Software Foundation; //// //// either version 2.1 of the License, or (at your option) any //// //// later version. //// //// //// //// This source is distributed in the hope that it will be //// //// useful, but WITHOUT ANY WARRANTY; without even the implied //// //// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR //// //// PURPOSE. See the GNU Lesser General Public License for more //// //// details. //// //// //// //// You should have received a copy of the GNU Lesser General //// //// Public License along with this source; if not, download it //// //// from http://www.opencores.org/lgpl.shtml //// //// //// ////////////////////////////////////////////////////////////////////// // // CVS Revision History // // $Log: not supported by cvs2svn $ // Revision 1.8 2004/04/05 08:29:57 lampret // Merged branch_qmem into main tree. // // Revision 1.7.4.1 2003/07/08 15:36:37 lampret // Added embedded memory QMEM. // // Revision 1.7 2002/03/29 15:16:55 lampret // Some of the warnings fixed. // // Revision 1.6 2002/03/28 19:10:40 lampret // Optimized cache controller FSM. // // Revision 1.1.1.1 2002/03/21 16:55:45 lampret // First import of the "new" XESS XSV environment. // // // Revision 1.5 2002/02/11 04:33:17 lampret // Speed optimizations (removed duplicate _cyc_ and _stb_). Fixed D/IMMU cache-inhibit attr. // // Revision 1.4 2002/02/01 19:56:54 lampret // Fixed combinational loops. // // Revision 1.3 2002/01/28 01:15:59 lampret // Changed 'void' nop-ops instead of insn[0] to use insn[16]. Debug unit stalls the tick timer. Prepared new flag generation for add and and insns. Blocked DC/IC while they are turned off. Fixed I/D MMU SPRs layout except WAYs. TODO: smart IC invalidate, l.j 2 and TLB ways. // // Revision 1.2 2002/01/14 06:18:22 lampret // Fixed mem2reg bug in FAST implementation. Updated debug unit to work with new genpc/if. // // Revision 1.1 2002/01/03 08:16:15 lampret // New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs. // // Revision 1.9 2001/10/21 17:57:16 lampret // Removed params from generic_XX.v. Added translate_off/on in sprs.v and id.v. Removed spr_addr from dc.v and ic.v. Fixed CR+LF. // // Revision 1.8 2001/10/19 23:28:46 lampret // Fixed some synthesis warnings. Configured with caches and MMUs. // // Revision 1.7 2001/10/14 13:12:09 lampret // MP3 version. // // Revision 1.1.1.1 2001/10/06 10:18:35 igorm // no message // // Revision 1.2 2001/08/09 13:39:33 lampret // Major clean-up. // // Revision 1.1 2001/07/20 00:46:03 lampret // Development version of RTL. Libraries are missing. // // // synopsys translate_off `include "timescale.v" // synopsys translate_on `include "or1200_defines.v" `define OR1200_DCFSM_IDLE 3'd0 `define OR1200_DCFSM_CLOAD 3'd1 `define OR1200_DCFSM_LREFILL3 3'd2 `define OR1200_DCFSM_CSTORE 3'd3 `define OR1200_DCFSM_SREFILL4 3'd4 // // Data cache FSM for cache line of 16 bytes (4x singleword) // module or1200_dc_fsm( // Clock and reset clk, rst, // Internal i/f to top level DC dc_en, dcqmem_cycstb_i, dcqmem_ci_i, dcqmem_we_i, dcqmem_sel_i, tagcomp_miss, biudata_valid, biudata_error, start_addr, saved_addr, dcram_we, biu_read, biu_write, first_hit_ack, first_miss_ack, first_miss_err, burst, tag_we, dc_addr ); // // I/O // input clk; input rst; input dc_en; input dcqmem_cycstb_i; input dcqmem_ci_i; input dcqmem_we_i; input [3:0] dcqmem_sel_i; input tagcomp_miss; input biudata_valid; input biudata_error; input [31:0] start_addr; output [31:0] saved_addr; output [3:0] dcram_we; output biu_read; output biu_write; output first_hit_ack; output first_miss_ack; output first_miss_err; output burst; output tag_we; output [31:0] dc_addr; // // Internal wires and regs // reg [31:0] saved_addr_r; reg [2:0] state; reg [2:0] cnt; reg hitmiss_eval; reg store; reg load; reg cache_inhibit; wire first_store_hit_ack; // // Generate of DCRAM write enables // assign dcram_we = {4{load & biudata_valid & !cache_inhibit}} | {4{first_store_hit_ack}} & dcqmem_sel_i; assign tag_we = biu_read & biudata_valid & !cache_inhibit; // // BIU read and write // assign biu_read = (hitmiss_eval & tagcomp_miss) | (!hitmiss_eval & load); assign biu_write = store; assign dc_addr = (biu_read | biu_write) & !hitmiss_eval ? saved_addr : start_addr; assign saved_addr = saved_addr_r; // // Assert for cache hit first word ready // Assert for store cache hit first word ready // Assert for cache miss first word stored/loaded OK // Assert for cache miss first word stored/loaded with an error // assign first_hit_ack = (state == `OR1200_DCFSM_CLOAD) & !tagcomp_miss & !cache_inhibit & !dcqmem_ci_i | first_store_hit_ack; assign first_store_hit_ack = (state == `OR1200_DCFSM_CSTORE) & !tagcomp_miss & biudata_valid & !cache_inhibit & !dcqmem_ci_i; assign first_miss_ack = ((state == `OR1200_DCFSM_CLOAD) | (state == `OR1200_DCFSM_CSTORE)) & biudata_valid; assign first_miss_err = ((state == `OR1200_DCFSM_CLOAD) | (state == `OR1200_DCFSM_CSTORE)) & biudata_error; // // Assert burst when doing reload of complete cache line // assign burst = (state == `OR1200_DCFSM_CLOAD) & tagcomp_miss & !cache_inhibit | (state == `OR1200_DCFSM_LREFILL3) `ifdef OR1200_DC_STORE_REFILL | (state == `OR1200_DCFSM_SREFILL4) `endif ; // // Main DC FSM // always @(posedge clk or posedge rst) begin if (rst) begin state <= #1 `OR1200_DCFSM_IDLE; saved_addr_r <= #1 32'b0; hitmiss_eval <= #1 1'b0; store <= #1 1'b0; load <= #1 1'b0; cnt <= #1 3'b000; cache_inhibit <= #1 1'b0; end else case (state) // synopsys parallel_case `OR1200_DCFSM_IDLE : if (dc_en & dcqmem_cycstb_i & dcqmem_we_i) begin // store state <= #1 `OR1200_DCFSM_CSTORE; saved_addr_r <= #1 start_addr; hitmiss_eval <= #1 1'b1; store <= #1 1'b1; load <= #1 1'b0; cache_inhibit <= #1 1'b0; end else if (dc_en & dcqmem_cycstb_i) begin // load state <= #1 `OR1200_DCFSM_CLOAD; saved_addr_r <= #1 start_addr; hitmiss_eval <= #1 1'b1; store <= #1 1'b0; load <= #1 1'b1; cache_inhibit <= #1 1'b0; end else begin // idle hitmiss_eval <= #1 1'b0; store <= #1 1'b0; load <= #1 1'b0; cache_inhibit <= #1 1'b0; end `OR1200_DCFSM_CLOAD: begin // load if (dcqmem_cycstb_i & dcqmem_ci_i) cache_inhibit <= #1 1'b1; if (hitmiss_eval) saved_addr_r[31:13] <= #1 start_addr[31:13]; if ((hitmiss_eval & !dcqmem_cycstb_i) || // load aborted (usually caused by DMMU) (biudata_error) || // load terminated with an error ((cache_inhibit | dcqmem_ci_i) & biudata_valid)) begin // load from cache-inhibited area state <= #1 `OR1200_DCFSM_IDLE; hitmiss_eval <= #1 1'b0; load <= #1 1'b0; cache_inhibit <= #1 1'b0; end else if (tagcomp_miss & biudata_valid) begin // load missed, finish current external load and refill state <= #1 `OR1200_DCFSM_LREFILL3; saved_addr_r[3:2] <= #1 saved_addr_r[3:2] + 1'd1; hitmiss_eval <= #1 1'b0; cnt <= #1 `OR1200_DCLS-2; cache_inhibit <= #1 1'b0; end else if (!tagcomp_miss & !dcqmem_ci_i) begin // load hit, finish immediately state <= #1 `OR1200_DCFSM_IDLE; hitmiss_eval <= #1 1'b0; load <= #1 1'b0; cache_inhibit <= #1 1'b0; end else // load in-progress hitmiss_eval <= #1 1'b0; end `OR1200_DCFSM_LREFILL3 : begin if (biudata_valid && (|cnt)) begin // refill ack, more loads to come cnt <= #1 cnt - 3'd1; saved_addr_r[3:2] <= #1 saved_addr_r[3:2] + 1'd1; end else if (biudata_valid) begin // last load of line refill state <= #1 `OR1200_DCFSM_IDLE; load <= #1 1'b0; end end `OR1200_DCFSM_CSTORE: begin // store if (dcqmem_cycstb_i & dcqmem_ci_i) cache_inhibit <= #1 1'b1; if (hitmiss_eval) saved_addr_r[31:13] <= #1 start_addr[31:13]; if ((hitmiss_eval & !dcqmem_cycstb_i) || // store aborted (usually caused by DMMU) (biudata_error) || // store terminated with an error ((cache_inhibit | dcqmem_ci_i) & biudata_valid)) begin // store to cache-inhibited area state <= #1 `OR1200_DCFSM_IDLE; hitmiss_eval <= #1 1'b0; store <= #1 1'b0; cache_inhibit <= #1 1'b0; end `ifdef OR1200_DC_STORE_REFILL else if (tagcomp_miss & biudata_valid) begin // store missed, finish write-through and doq load refill state <= #1 `OR1200_DCFSM_SREFILL4; hitmiss_eval <= #1 1'b0; store <= #1 1'b0; load <= #1 1'b1; cnt <= #1 `OR1200_DCLS-1; cache_inhibit <= #1 1'b0; end `endif else if (biudata_valid) begin // store hit, finish write-through state <= #1 `OR1200_DCFSM_IDLE; hitmiss_eval <= #1 1'b0; store <= #1 1'b0; cache_inhibit <= #1 1'b0; end else // store write-through in-progress hitmiss_eval <= #1 1'b0; end `ifdef OR1200_DC_STORE_REFILL `OR1200_DCFSM_SREFILL4 : begin if (biudata_valid && (|cnt)) begin // refill ack, more loads to come cnt <= #1 cnt - 1'd1; saved_addr_r[3:2] <= #1 saved_addr_r[3:2] + 1'd1; end else if (biudata_valid) begin // last load of line refill state <= #1 `OR1200_DCFSM_IDLE; load <= #1 1'b0; end end `endif default: state <= #1 `OR1200_DCFSM_IDLE; endcase end endmodule
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