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ao486_MiSTer/rtl/ao486/memory/memory_write.v

233 lines
7.2 KiB
Verilog

/*
* Copyright (c) 2014, Aleksander Osman
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
`include "defines.v"
//PARSED_COMMENTS: this file contains parsed script comments
module memory_write(
input clk,
input rst_n,
// write step
input wr_reset,
//RESP:
input write_do,
output write_done,
output write_page_fault,
output write_ac_fault,
input [1:0] write_cpl,
input [31:0] write_address,
input [2:0] write_length,
input write_lock,
input write_rmw,
input [31:0] write_data,
//END
//REQ: done at least one cycle later, do has to wait for doing
output tlbwrite_do,
input tlbwrite_done,
input tlbwrite_page_fault,
input tlbwrite_ac_fault,
output [1:0] tlbwrite_cpl,
output [31:0] tlbwrite_address,
output [2:0] tlbwrite_length,
output [2:0] tlbwrite_length_full,
output tlbwrite_lock,
output tlbwrite_rmw,
output [31:0] tlbwrite_data
//END
);
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
reg [1:0] state;
reg [23:0] buffer;
reg [2:0] length_2_reg;
reg [31:0] address_2_reg;
reg reset_waiting;
reg page_fault;
reg ac_fault;
//------------------------------------------------------------------------------
wire [4:0] left_in_line;
wire [2:0] length_1;
wire [2:0] length_2;
wire [31:0] address_2;
//------------------------------------------------------------------------------
assign write_page_fault = tlbwrite_page_fault || page_fault;
assign write_ac_fault = tlbwrite_ac_fault || ac_fault;
assign left_in_line = 5'd16 - { 1'b0, write_address[3:0] };
assign length_1 = (left_in_line >= { 2'd0, write_length })? write_length : left_in_line[2:0];
assign length_2 = write_length - length_1;
assign address_2 = { write_address[31:4], 4'd0 } + 32'd16;
assign tlbwrite_cpl = write_cpl;
assign tlbwrite_length_full = write_length;
assign tlbwrite_lock = write_lock;
assign tlbwrite_rmw = write_rmw;
//------------------------------------------------------------------------------
localparam [1:0] STATE_IDLE = 2'd0;
localparam [1:0] STATE_FIRST_WAIT = 2'd1;
localparam [1:0] STATE_SECOND = 2'd2;
always @(posedge clk) begin
if(rst_n == 1'b0) reset_waiting <= `FALSE;
else if(wr_reset && state != STATE_IDLE) reset_waiting <= `TRUE;
else if(state == STATE_IDLE) reset_waiting <= `FALSE;
end
always @(posedge clk) begin
if(rst_n == 1'b0) page_fault <= `FALSE;
else if(wr_reset) page_fault <= `FALSE;
else if(tlbwrite_page_fault && ~(reset_waiting)) page_fault <= `TRUE;
end
always @(posedge clk) begin
if(rst_n == 1'b0) ac_fault <= `FALSE;
else if(wr_reset) ac_fault <= `FALSE;
else if(tlbwrite_ac_fault && ~(reset_waiting)) ac_fault <= `TRUE;
end
//------------------------------------------------------------------------------
// synthesis translate_off
wire _unused_ok = &{ 1'b0, address_2[3:0], 1'b0 };
// synthesis translate_on
//------------------------------------------------------------------------------
/*
tlbwrite_cpl -- constant assign from read
tlbwrite_address -- set
tlbwrite_length -- set
tlbwrite_length_full -- constant assign from read
tlbwrite_lock -- constant assign from read
tlbwrite_rmw -- constant assign from read
tlbwrite_data -- set
*/
/*******************************************************************************SCRIPT
IF(state == STATE_IDLE);
IF(length_1 == 3'd1); SAVE(buffer, write_data[31:8]);
ELSE_IF(length_1 == 3'd2); SAVE(buffer, { 8'd0, write_data[31:16] });
ELSE(); SAVE(buffer, { 16'd0, write_data[31:24] });
ENDIF();
SAVE(length_2_reg, length_2);
SAVE(address_2_reg, { address_2[31:4], 4'd0 });
SET(tlbwrite_address, write_address);
SET(tlbwrite_length, length_1);
SET(tlbwrite_data, write_data);
IF(write_do && ~(wr_reset) && ~(write_page_fault) && ~(write_ac_fault));
SET(tlbwrite_do);
SAVE(state, STATE_FIRST_WAIT);
ENDIF();
ENDIF();
*/
/*******************************************************************************SCRIPT
IF(state == STATE_FIRST_WAIT);
SET(tlbwrite_do);
SET(tlbwrite_address, write_address);
SET(tlbwrite_length, length_1);
SET(tlbwrite_data, write_data);
IF(tlbwrite_page_fault || tlbwrite_ac_fault);
SAVE(state, STATE_IDLE);
ELSE_IF(tlbwrite_done && length_2_reg != 3'd0);
SAVE(state, STATE_SECOND);
ELSE_IF(tlbwrite_done);
IF(reset_waiting == `FALSE); SET(write_done); ENDIF(); //does not depend on: wr_reset == `FALSE
SAVE(state, STATE_IDLE);
ENDIF();
ENDIF();
*/
/*******************************************************************************SCRIPT
IF(state == STATE_SECOND);
SET(tlbwrite_do);
SET(tlbwrite_address, address_2_reg);
SET(tlbwrite_length, length_2_reg);
SET(tlbwrite_data, { 8'd0, buffer });
IF(tlbwrite_page_fault || tlbwrite_ac_fault || tlbwrite_done);
SAVE(state, STATE_IDLE);
ENDIF();
IF(tlbwrite_done && reset_waiting == `FALSE); //does not depend on: wr_reset == `FALSE
SET(write_done);
ENDIF();
ENDIF();
*/
//------------------------------------------------------------------------------
`include "autogen/memory_write.v"
endmodule