lm32_dcache.v

changeset 24
c336e674a37e
parent 23
252df75c8f67
child 25
7422134cbfea
     1.1 diff -r 252df75c8f67 -r c336e674a37e lm32_dcache.v
     1.2 --- a/lm32_dcache.v	Sun Mar 06 21:17:31 2011 +0000
     1.3 +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.4 @@ -1,542 +0,0 @@
     1.5 -// =============================================================================
     1.6 -//                           COPYRIGHT NOTICE
     1.7 -// Copyright 2006 (c) Lattice Semiconductor Corporation
     1.8 -// ALL RIGHTS RESERVED
     1.9 -// This confidential and proprietary software may be used only as authorised by
    1.10 -// a licensing agreement from Lattice Semiconductor Corporation.
    1.11 -// The entire notice above must be reproduced on all authorized copies and
    1.12 -// copies may only be made to the extent permitted by a licensing agreement from
    1.13 -// Lattice Semiconductor Corporation.
    1.14 -//
    1.15 -// Lattice Semiconductor Corporation        TEL : 1-800-Lattice (USA and Canada)
    1.16 -// 5555 NE Moore Court                            408-826-6000 (other locations)
    1.17 -// Hillsboro, OR 97124                     web  : http://www.latticesemi.com/
    1.18 -// U.S.A                                   email: techsupport@latticesemi.com
    1.19 -// =============================================================================/
    1.20 -//                         FILE DETAILS
    1.21 -// Project          : LatticeMico32
    1.22 -// File             : lm32_dcache.v
    1.23 -// Title            : Data cache
    1.24 -// Dependencies     : lm32_include.v
    1.25 -// Version          : 6.1.17
    1.26 -//                  : Initial Release
    1.27 -// Version          : 7.0SP2, 3.0
    1.28 -//                  : No Change
    1.29 -// Version	    : 3.1
    1.30 -//                  : Support for user-selected resource usage when implementing
    1.31 -//                  : cache memory. Additional parameters must be defined when
    1.32 -//                  : invoking lm32_ram.v
    1.33 -// =============================================================================
    1.34 -								 
    1.35 -`include "lm32_include.v"
    1.36 -
    1.37 -`ifdef CFG_DCACHE_ENABLED
    1.38 -
    1.39 -`define LM32_DC_ADDR_OFFSET_RNG          addr_offset_msb:addr_offset_lsb
    1.40 -`define LM32_DC_ADDR_SET_RNG             addr_set_msb:addr_set_lsb
    1.41 -`define LM32_DC_ADDR_TAG_RNG             addr_tag_msb:addr_tag_lsb
    1.42 -`define LM32_DC_ADDR_IDX_RNG             addr_set_msb:addr_offset_lsb
    1.43 -
    1.44 -`define LM32_DC_TMEM_ADDR_WIDTH          addr_set_width
    1.45 -`define LM32_DC_TMEM_ADDR_RNG            (`LM32_DC_TMEM_ADDR_WIDTH-1):0
    1.46 -`define LM32_DC_DMEM_ADDR_WIDTH          (addr_offset_width+addr_set_width)
    1.47 -`define LM32_DC_DMEM_ADDR_RNG            (`LM32_DC_DMEM_ADDR_WIDTH-1):0
    1.48 -
    1.49 -`define LM32_DC_TAGS_WIDTH               (addr_tag_width+1)
    1.50 -`define LM32_DC_TAGS_RNG                 (`LM32_DC_TAGS_WIDTH-1):0
    1.51 -`define LM32_DC_TAGS_TAG_RNG             (`LM32_DC_TAGS_WIDTH-1):1
    1.52 -`define LM32_DC_TAGS_VALID_RNG           0
    1.53 -
    1.54 -`define LM32_DC_STATE_RNG                2:0
    1.55 -`define LM32_DC_STATE_FLUSH              3'b001
    1.56 -`define LM32_DC_STATE_CHECK              3'b010
    1.57 -`define LM32_DC_STATE_REFILL             3'b100
    1.58 -
    1.59 -/////////////////////////////////////////////////////
    1.60 -// Module interface
    1.61 -/////////////////////////////////////////////////////
    1.62 -
    1.63 -module lm32_dcache ( 
    1.64 -    // ----- Inputs -----
    1.65 -    clk_i,
    1.66 -    rst_i,    
    1.67 -    stall_a,
    1.68 -    stall_x,
    1.69 -    stall_m,
    1.70 -    address_x,
    1.71 -    address_m,
    1.72 -    load_q_m,
    1.73 -    store_q_m,
    1.74 -    store_data,
    1.75 -    store_byte_select,
    1.76 -    refill_ready,
    1.77 -    refill_data,
    1.78 -    dflush,
    1.79 -    // ----- Outputs -----
    1.80 -    stall_request,
    1.81 -    restart_request,
    1.82 -    refill_request,
    1.83 -    refill_address,
    1.84 -    refilling,
    1.85 -    load_data
    1.86 -    );
    1.87 -
    1.88 -/////////////////////////////////////////////////////
    1.89 -// Parameters
    1.90 -/////////////////////////////////////////////////////
    1.91 -
    1.92 -parameter associativity = 1;                            // Associativity of the cache (Number of ways)
    1.93 -parameter sets = 512;                                   // Number of sets
    1.94 -parameter bytes_per_line = 16;                          // Number of bytes per cache line
    1.95 -parameter base_address = 0;                             // Base address of cachable memory
    1.96 -parameter limit = 0;                                    // Limit (highest address) of cachable memory
    1.97 -
    1.98 -localparam addr_offset_width = clogb2(bytes_per_line)-1-2;
    1.99 -localparam addr_set_width = clogb2(sets)-1;
   1.100 -localparam addr_offset_lsb = 2;
   1.101 -localparam addr_offset_msb = (addr_offset_lsb+addr_offset_width-1);
   1.102 -localparam addr_set_lsb = (addr_offset_msb+1);
   1.103 -localparam addr_set_msb = (addr_set_lsb+addr_set_width-1);
   1.104 -localparam addr_tag_lsb = (addr_set_msb+1);
   1.105 -localparam addr_tag_msb = clogb2(`CFG_DCACHE_LIMIT-`CFG_DCACHE_BASE_ADDRESS)-1;
   1.106 -localparam addr_tag_width = (addr_tag_msb-addr_tag_lsb+1);
   1.107 -
   1.108 -/////////////////////////////////////////////////////
   1.109 -// Inputs
   1.110 -/////////////////////////////////////////////////////
   1.111 -
   1.112 -input clk_i;                                            // Clock
   1.113 -input rst_i;                                            // Reset
   1.114 -
   1.115 -input stall_a;                                          // Stall A stage
   1.116 -input stall_x;                                          // Stall X stage
   1.117 -input stall_m;                                          // Stall M stage
   1.118 -
   1.119 -input [`LM32_WORD_RNG] address_x;                       // X stage load/store address
   1.120 -input [`LM32_WORD_RNG] address_m;                       // M stage load/store address
   1.121 -input load_q_m;                                         // Load instruction in M stage
   1.122 -input store_q_m;                                        // Store instruction in M stage
   1.123 -input [`LM32_WORD_RNG] store_data;                      // Data to store
   1.124 -input [`LM32_BYTE_SELECT_RNG] store_byte_select;        // Which bytes in store data should be modified
   1.125 -
   1.126 -input refill_ready;                                     // Indicates next word of refill data is ready
   1.127 -input [`LM32_WORD_RNG] refill_data;                     // Refill data
   1.128 -
   1.129 -input dflush;                                           // Indicates cache should be flushed
   1.130 -
   1.131 -/////////////////////////////////////////////////////
   1.132 -// Outputs
   1.133 -/////////////////////////////////////////////////////
   1.134 -
   1.135 -output stall_request;                                   // Request pipeline be stalled because cache is busy
   1.136 -wire   stall_request;
   1.137 -output restart_request;                                 // Request to restart instruction that caused the cache miss
   1.138 -reg    restart_request;
   1.139 -output refill_request;                                  // Request a refill 
   1.140 -reg    refill_request;
   1.141 -output [`LM32_WORD_RNG] refill_address;                 // Address to refill from
   1.142 -reg    [`LM32_WORD_RNG] refill_address;
   1.143 -output refilling;                                       // Indicates if the cache is currently refilling
   1.144 -reg    refilling;
   1.145 -output [`LM32_WORD_RNG] load_data;                      // Data read from cache
   1.146 -wire   [`LM32_WORD_RNG] load_data;
   1.147 -
   1.148 -/////////////////////////////////////////////////////
   1.149 -// Internal nets and registers 
   1.150 -/////////////////////////////////////////////////////
   1.151 -
   1.152 -wire read_port_enable;                                  // Cache memory read port clock enable
   1.153 -wire write_port_enable;                                 // Cache memory write port clock enable
   1.154 -wire [0:associativity-1] way_tmem_we;                   // Tag memory write enable
   1.155 -wire [0:associativity-1] way_dmem_we;                   // Data memory write enable
   1.156 -wire [`LM32_WORD_RNG] way_data[0:associativity-1];      // Data read from data memory
   1.157 -wire [`LM32_DC_TAGS_TAG_RNG] way_tag[0:associativity-1];// Tag read from tag memory
   1.158 -wire [0:associativity-1] way_valid;                     // Indicates which ways are valid
   1.159 -wire [0:associativity-1] way_match;                     // Indicates which ways matched
   1.160 -wire miss;                                              // Indicates no ways matched
   1.161 -
   1.162 -wire [`LM32_DC_TMEM_ADDR_RNG] tmem_read_address;        // Tag memory read address
   1.163 -wire [`LM32_DC_TMEM_ADDR_RNG] tmem_write_address;       // Tag memory write address
   1.164 -wire [`LM32_DC_DMEM_ADDR_RNG] dmem_read_address;        // Data memory read address
   1.165 -wire [`LM32_DC_DMEM_ADDR_RNG] dmem_write_address;       // Data memory write address
   1.166 -wire [`LM32_DC_TAGS_RNG] tmem_write_data;               // Tag memory write data        
   1.167 -reg [`LM32_WORD_RNG] dmem_write_data;                   // Data memory write data
   1.168 -
   1.169 -reg [`LM32_DC_STATE_RNG] state;                         // Current state of FSM
   1.170 -wire flushing;                                          // Indicates if cache is currently flushing
   1.171 -wire check;                                             // Indicates if cache is currently checking for hits/misses
   1.172 -wire refill;                                            // Indicates if cache is currently refilling
   1.173 -
   1.174 -wire valid_store;                                       // Indicates if there is a valid store instruction
   1.175 -reg [associativity-1:0] refill_way_select;              // Which way should be refilled
   1.176 -reg [`LM32_DC_ADDR_OFFSET_RNG] refill_offset;           // Which word in cache line should be refilled
   1.177 -wire last_refill;                                       // Indicates when on last cycle of cache refill
   1.178 -reg [`LM32_DC_TMEM_ADDR_RNG] flush_set;                 // Which set is currently being flushed
   1.179 -
   1.180 -genvar i, j;
   1.181 -
   1.182 -/////////////////////////////////////////////////////
   1.183 -// Functions
   1.184 -/////////////////////////////////////////////////////
   1.185 -
   1.186 -`include "lm32_functions.v"
   1.187 -
   1.188 -/////////////////////////////////////////////////////
   1.189 -// Instantiations
   1.190 -/////////////////////////////////////////////////////
   1.191 -
   1.192 -   generate
   1.193 -      for (i = 0; i < associativity; i = i + 1)    
   1.194 -	begin : memories
   1.195 -	   // Way data
   1.196 -           if (`LM32_DC_DMEM_ADDR_WIDTH < 11)
   1.197 -             begin : data_memories
   1.198 -		lm32_ram 
   1.199 -		  #(
   1.200 -		    // ----- Parameters -------
   1.201 -		    .data_width (32),
   1.202 -		    .address_width (`LM32_DC_DMEM_ADDR_WIDTH)
   1.203 -`ifdef PLATFORM_LATTICE
   1.204 -			,
   1.205 - `ifdef CFG_DCACHE_DAT_USE_DP_TRUE
   1.206 -		    .RAM_IMPLEMENTATION ("EBR"),
   1.207 -		    .RAM_TYPE ("RAM_DP_TRUE")
   1.208 - `else
   1.209 -  `ifdef CFG_DCACHE_DAT_USE_SLICE
   1.210 -		    .RAM_IMPLEMENTATION ("SLICE")
   1.211 -  `else
   1.212 -		    .RAM_IMPLEMENTATION ("AUTO")
   1.213 -  `endif
   1.214 - `endif
   1.215 -`endif
   1.216 -		    ) way_0_data_ram 
   1.217 -		    (
   1.218 -		     // ----- Inputs -------
   1.219 -		     .read_clk (clk_i),
   1.220 -		     .write_clk (clk_i),
   1.221 -		     .reset (rst_i),
   1.222 -		     .read_address (dmem_read_address),
   1.223 -		     .enable_read (read_port_enable),
   1.224 -		     .write_address (dmem_write_address),
   1.225 -		     .enable_write (write_port_enable),
   1.226 -		     .write_enable (way_dmem_we[i]),
   1.227 -		     .write_data (dmem_write_data),    
   1.228 -		     // ----- Outputs -------
   1.229 -		     .read_data (way_data[i])
   1.230 -		     );    
   1.231 -             end
   1.232 -           else
   1.233 -             begin
   1.234 -		for (j = 0; j < 4; j = j + 1)    
   1.235 -		  begin : byte_memories
   1.236 -		     lm32_ram 
   1.237 -		       #(
   1.238 -			 // ----- Parameters -------
   1.239 -			 .data_width (8),
   1.240 -			 .address_width (`LM32_DC_DMEM_ADDR_WIDTH)
   1.241 -`ifdef PLATFORM_LATTICE
   1.242 -			 ,
   1.243 - `ifdef CFG_DCACHE_DAT_USE_DP_TRUE
   1.244 -			 .RAM_IMPLEMENTATION ("EBR"),
   1.245 -			 .RAM_TYPE ("RAM_DP_TRUE")
   1.246 - `else
   1.247 -  `ifdef CFG_DCACHE_DAT_USE_SLICE
   1.248 -			 .RAM_IMPLEMENTATION ("SLICE")
   1.249 -  `else
   1.250 -			 .RAM_IMPLEMENTATION ("AUTO")
   1.251 -  `endif
   1.252 - `endif
   1.253 -`endif
   1.254 -			 ) way_0_data_ram 
   1.255 -			 (
   1.256 -			  // ----- Inputs -------
   1.257 -			  .read_clk (clk_i),
   1.258 -			  .write_clk (clk_i),
   1.259 -			  .reset (rst_i),
   1.260 -			  .read_address (dmem_read_address),
   1.261 -			  .enable_read (read_port_enable),
   1.262 -			  .write_address (dmem_write_address),
   1.263 -			  .enable_write (write_port_enable),
   1.264 -			  .write_enable (way_dmem_we[i] & (store_byte_select[j] | refill)),
   1.265 -			  .write_data (dmem_write_data[(j+1)*8-1:j*8]),    
   1.266 -			  // ----- Outputs -------
   1.267 -			  .read_data (way_data[i][(j+1)*8-1:j*8])
   1.268 -			  );
   1.269 -		  end
   1.270 -             end
   1.271 -	   
   1.272 -	   // Way tags
   1.273 -	   lm32_ram 
   1.274 -	     #(
   1.275 -	       // ----- Parameters -------
   1.276 -	       .data_width (`LM32_DC_TAGS_WIDTH),
   1.277 -	       .address_width (`LM32_DC_TMEM_ADDR_WIDTH)
   1.278 -`ifdef PLATFORM_LATTICE
   1.279 -			 ,
   1.280 - `ifdef CFG_DCACHE_DAT_USE_DP_TRUE
   1.281 -	       .RAM_IMPLEMENTATION ("EBR"),
   1.282 -	       .RAM_TYPE ("RAM_DP_TRUE")
   1.283 - `else
   1.284 -  `ifdef CFG_DCACHE_DAT_USE_SLICE
   1.285 -	       .RAM_IMPLEMENTATION ("SLICE")
   1.286 -  `else
   1.287 -	       .RAM_IMPLEMENTATION ("AUTO")
   1.288 -  `endif
   1.289 - `endif
   1.290 -`endif
   1.291 -	       ) way_0_tag_ram 
   1.292 -	       (
   1.293 -		// ----- Inputs -------
   1.294 -		.read_clk (clk_i),
   1.295 -		.write_clk (clk_i),
   1.296 -		.reset (rst_i),
   1.297 -		.read_address (tmem_read_address),
   1.298 -		.enable_read (read_port_enable),
   1.299 -		.write_address (tmem_write_address),
   1.300 -		.enable_write (`TRUE),
   1.301 -		.write_enable (way_tmem_we[i]),
   1.302 -		.write_data (tmem_write_data),
   1.303 -		// ----- Outputs -------
   1.304 -		.read_data ({way_tag[i], way_valid[i]})
   1.305 -		);
   1.306 -	end
   1.307 -      
   1.308 -   endgenerate
   1.309 -
   1.310 -/////////////////////////////////////////////////////
   1.311 -// Combinational logic
   1.312 -/////////////////////////////////////////////////////
   1.313 -
   1.314 -// Compute which ways in the cache match the address being read
   1.315 -generate
   1.316 -    for (i = 0; i < associativity; i = i + 1)
   1.317 -    begin : match
   1.318 -assign way_match[i] = ({way_tag[i], way_valid[i]} == {address_m[`LM32_DC_ADDR_TAG_RNG], `TRUE});
   1.319 -    end
   1.320 -endgenerate
   1.321 -
   1.322 -// Select data from way that matched the address being read     
   1.323 -generate
   1.324 -    if (associativity == 1)    
   1.325 -	 begin : data_1
   1.326 -assign load_data = way_data[0];
   1.327 -    end
   1.328 -    else if (associativity == 2)
   1.329 -	 begin : data_2
   1.330 -assign load_data = way_match[0] ? way_data[0] : way_data[1]; 
   1.331 -    end
   1.332 -endgenerate
   1.333 -
   1.334 -generate
   1.335 -    if (`LM32_DC_DMEM_ADDR_WIDTH < 11)
   1.336 -    begin
   1.337 -// Select data to write to data memories
   1.338 -always @(*)
   1.339 -begin
   1.340 -    if (refill == `TRUE)
   1.341 -        dmem_write_data = refill_data;
   1.342 -    else
   1.343 -    begin
   1.344 -        dmem_write_data[`LM32_BYTE_0_RNG] = store_byte_select[0] ? store_data[`LM32_BYTE_0_RNG] : load_data[`LM32_BYTE_0_RNG];
   1.345 -        dmem_write_data[`LM32_BYTE_1_RNG] = store_byte_select[1] ? store_data[`LM32_BYTE_1_RNG] : load_data[`LM32_BYTE_1_RNG];
   1.346 -        dmem_write_data[`LM32_BYTE_2_RNG] = store_byte_select[2] ? store_data[`LM32_BYTE_2_RNG] : load_data[`LM32_BYTE_2_RNG];
   1.347 -        dmem_write_data[`LM32_BYTE_3_RNG] = store_byte_select[3] ? store_data[`LM32_BYTE_3_RNG] : load_data[`LM32_BYTE_3_RNG];
   1.348 -    end
   1.349 -end
   1.350 -    end
   1.351 -    else
   1.352 -    begin
   1.353 -// Select data to write to data memories - FIXME: Should use different write ports on dual port RAMs, but they don't work
   1.354 -always @(*)
   1.355 -begin
   1.356 -    if (refill == `TRUE)
   1.357 -        dmem_write_data = refill_data;
   1.358 -    else
   1.359 -        dmem_write_data = store_data;
   1.360 -end
   1.361 -    end
   1.362 -endgenerate
   1.363 -
   1.364 -// Compute address to use to index into the data memories
   1.365 -generate 
   1.366 -     if (bytes_per_line > 4)
   1.367 -assign dmem_write_address = (refill == `TRUE) 
   1.368 -                            ? {refill_address[`LM32_DC_ADDR_SET_RNG], refill_offset}
   1.369 -                            : address_m[`LM32_DC_ADDR_IDX_RNG];
   1.370 -    else
   1.371 -assign dmem_write_address = (refill == `TRUE) 
   1.372 -                            ? refill_address[`LM32_DC_ADDR_SET_RNG]
   1.373 -                            : address_m[`LM32_DC_ADDR_IDX_RNG];
   1.374 -endgenerate
   1.375 -assign dmem_read_address = address_x[`LM32_DC_ADDR_IDX_RNG];
   1.376 -// Compute address to use to index into the tag memories   
   1.377 -assign tmem_write_address = (flushing == `TRUE)
   1.378 -                            ? flush_set
   1.379 -                            : refill_address[`LM32_DC_ADDR_SET_RNG];
   1.380 -assign tmem_read_address = address_x[`LM32_DC_ADDR_SET_RNG];
   1.381 -
   1.382 -// Compute signal to indicate when we are on the last refill accesses
   1.383 -generate 
   1.384 -    if (bytes_per_line > 4)                            
   1.385 -assign last_refill = refill_offset == {addr_offset_width{1'b1}};
   1.386 -    else
   1.387 -assign last_refill = `TRUE;
   1.388 -endgenerate
   1.389 -
   1.390 -// Compute data and tag memory access enable
   1.391 -assign read_port_enable = (stall_x == `FALSE);
   1.392 -assign write_port_enable = (refill_ready == `TRUE) || !stall_m;
   1.393 -
   1.394 -// Determine when we have a valid store
   1.395 -assign valid_store = (store_q_m == `TRUE) && (check == `TRUE);
   1.396 -
   1.397 -// Compute data and tag memory write enables
   1.398 -generate
   1.399 -    if (associativity == 1) 
   1.400 -    begin : we_1     
   1.401 -assign way_dmem_we[0] = (refill_ready == `TRUE) || ((valid_store == `TRUE) && (way_match[0] == `TRUE));
   1.402 -assign way_tmem_we[0] = (refill_ready == `TRUE) || (flushing == `TRUE);
   1.403 -    end 
   1.404 -    else 
   1.405 -    begin : we_2
   1.406 -assign way_dmem_we[0] = ((refill_ready == `TRUE) && (refill_way_select[0] == `TRUE)) || ((valid_store == `TRUE) && (way_match[0] == `TRUE));
   1.407 -assign way_dmem_we[1] = ((refill_ready == `TRUE) && (refill_way_select[1] == `TRUE)) || ((valid_store == `TRUE) && (way_match[1] == `TRUE));
   1.408 -assign way_tmem_we[0] = ((refill_ready == `TRUE) && (refill_way_select[0] == `TRUE)) || (flushing == `TRUE);
   1.409 -assign way_tmem_we[1] = ((refill_ready == `TRUE) && (refill_way_select[1] == `TRUE)) || (flushing == `TRUE);
   1.410 -    end
   1.411 -endgenerate
   1.412 -
   1.413 -// On the last refill cycle set the valid bit, for all other writes it should be cleared
   1.414 -assign tmem_write_data[`LM32_DC_TAGS_VALID_RNG] = ((last_refill == `TRUE) || (valid_store == `TRUE)) && (flushing == `FALSE);
   1.415 -assign tmem_write_data[`LM32_DC_TAGS_TAG_RNG] = refill_address[`LM32_DC_ADDR_TAG_RNG];
   1.416 -
   1.417 -// Signals that indicate which state we are in
   1.418 -assign flushing = state[0];
   1.419 -assign check = state[1];
   1.420 -assign refill = state[2];
   1.421 -
   1.422 -assign miss = (~(|way_match)) && (load_q_m == `TRUE) && (stall_m == `FALSE);
   1.423 -assign stall_request = (check == `FALSE);
   1.424 -                      
   1.425 -/////////////////////////////////////////////////////
   1.426 -// Sequential logic
   1.427 -/////////////////////////////////////////////////////
   1.428 -
   1.429 -// Record way selected for replacement on a cache miss
   1.430 -generate
   1.431 -    if (associativity >= 2) 
   1.432 -    begin : way_select      
   1.433 -always @(posedge clk_i `CFG_RESET_SENSITIVITY)
   1.434 -begin
   1.435 -    if (rst_i == `TRUE)
   1.436 -        refill_way_select <= {{associativity-1{1'b0}}, 1'b1};
   1.437 -    else
   1.438 -    begin        
   1.439 -        if (refill_request == `TRUE)
   1.440 -            refill_way_select <= {refill_way_select[0], refill_way_select[1]};
   1.441 -    end
   1.442 -end
   1.443 -    end 
   1.444 -endgenerate   
   1.445 -
   1.446 -// Record whether we are currently refilling
   1.447 -always @(posedge clk_i `CFG_RESET_SENSITIVITY)
   1.448 -begin
   1.449 -    if (rst_i == `TRUE)
   1.450 -        refilling <= `FALSE;
   1.451 -    else 
   1.452 -        refilling <= refill;
   1.453 -end
   1.454 -
   1.455 -// Instruction cache control FSM
   1.456 -always @(posedge clk_i `CFG_RESET_SENSITIVITY)
   1.457 -begin
   1.458 -    if (rst_i == `TRUE)
   1.459 -    begin
   1.460 -        state <= `LM32_DC_STATE_FLUSH;
   1.461 -        flush_set <= {`LM32_DC_TMEM_ADDR_WIDTH{1'b1}};
   1.462 -        refill_request <= `FALSE;
   1.463 -        refill_address <= {`LM32_WORD_WIDTH{1'bx}};
   1.464 -        restart_request <= `FALSE;
   1.465 -    end
   1.466 -    else 
   1.467 -    begin
   1.468 -        case (state)
   1.469 -
   1.470 -        // Flush the cache 
   1.471 -        `LM32_DC_STATE_FLUSH:
   1.472 -        begin
   1.473 -            if (flush_set == {`LM32_DC_TMEM_ADDR_WIDTH{1'b0}})
   1.474 -                state <= `LM32_DC_STATE_CHECK;
   1.475 -            flush_set <= flush_set - 1'b1;
   1.476 -        end
   1.477 -        
   1.478 -        // Check for cache misses
   1.479 -        `LM32_DC_STATE_CHECK:
   1.480 -        begin
   1.481 -            if (stall_a == `FALSE)
   1.482 -                restart_request <= `FALSE;
   1.483 -            if (miss == `TRUE)
   1.484 -            begin
   1.485 -                refill_request <= `TRUE;
   1.486 -                refill_address <= address_m;
   1.487 -                state <= `LM32_DC_STATE_REFILL;
   1.488 -            end
   1.489 -            else if (dflush == `TRUE)
   1.490 -                state <= `LM32_DC_STATE_FLUSH;
   1.491 -        end
   1.492 -
   1.493 -        // Refill a cache line
   1.494 -        `LM32_DC_STATE_REFILL:
   1.495 -        begin
   1.496 -            refill_request <= `FALSE;
   1.497 -            if (refill_ready == `TRUE)
   1.498 -            begin
   1.499 -                if (last_refill == `TRUE)
   1.500 -                begin
   1.501 -                    restart_request <= `TRUE;
   1.502 -                    state <= `LM32_DC_STATE_CHECK;
   1.503 -                end
   1.504 -            end
   1.505 -        end
   1.506 -        
   1.507 -        endcase        
   1.508 -    end
   1.509 -end
   1.510 -
   1.511 -generate
   1.512 -    if (bytes_per_line > 4)
   1.513 -    begin
   1.514 -// Refill offset
   1.515 -always @(posedge clk_i `CFG_RESET_SENSITIVITY)
   1.516 -begin
   1.517 -    if (rst_i == `TRUE)
   1.518 -        refill_offset <= {addr_offset_width{1'b0}};
   1.519 -    else 
   1.520 -    begin
   1.521 -        case (state)
   1.522 -        
   1.523 -        // Check for cache misses
   1.524 -        `LM32_DC_STATE_CHECK:
   1.525 -        begin
   1.526 -            if (miss == `TRUE)
   1.527 -                refill_offset <= {addr_offset_width{1'b0}};
   1.528 -        end
   1.529 -
   1.530 -        // Refill a cache line
   1.531 -        `LM32_DC_STATE_REFILL:
   1.532 -        begin
   1.533 -            if (refill_ready == `TRUE)
   1.534 -                refill_offset <= refill_offset + 1'b1;
   1.535 -        end
   1.536 -        
   1.537 -        endcase        
   1.538 -    end
   1.539 -end
   1.540 -    end
   1.541 -endgenerate
   1.542 -
   1.543 -endmodule
   1.544 -
   1.545 -`endif
   1.546 -