Subversion Repositories rf6809

// ============================================================================
//        __
//   \\__/ o\    (C) 2012-2022  Robert Finch, Waterloo
//    \  __ /    All rights reserved.
//     \/_//     robfinch<remove>@finitron.ca
//       ||
//
//
// BSD 3-Clause License
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
//
// 2. 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.
//
// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// 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.
//                                                                          
// ============================================================================
//
module scratchmem(rst_i, clk_i, cti_i, bok_o, cs_i, cyc_i, stb_i, ack_o, we_i, adr_i, dat_i, dat_o, sp);
input rst_i;
input clk_i;
input [2:0] cti_i;
output bok_o;
input cs_i;
input cyc_i;
input stb_i;
output ack_o;
input we_i;
input [13:0] adr_i;
input [11:0] dat_i;
output reg [11:0] dat_o;
input [23:0] sp;

integer n;

reg [11:0] rommem [16383:0];
reg [13:0] radr;


initial begin
        for (n = 0; n < 16384; n = n + 1)
                rommem[n] <= 'h00;
`include "d:/cores2022/rf6809/software/a09/a09/debug/boot_rom.ver";
end

wire cs = cs_i && cyc_i && stb_i;
assign bok_o = cs_i;
reg csd = 1'b0;
reg wed = 1'b0;
reg [13:0] adrd = 16'h00;
reg [11:0] datid = 8'h00;
reg [11:0] datod = 'h00;

reg [2:0] cnt;

ack_gen #(
        .READ_STAGES(2),
        .WRITE_STAGES(1),
        .REGISTER_OUTPUT(1)
) ag1
(
        .clk_i(clk_i),
        .ce_i(1'b1),
        .i(cs && cnt != 3'b101),
        .we_i(we_i && cs && cnt != 3'b101),
        .o(ack_o),
        .rid_i(0),
        .wid_i(0),
        .rid_o(),
        .wid_o()
);


always @(posedge clk_i)
        csd <= cs;
always @(posedge clk_i)
        wed <= we_i;
always @(posedge clk_i)
        adrd <= adr_i;
always @(posedge clk_i)
        datid <= dat_i;

always @(posedge clk_i)
        if (cs & we_i) begin
                $display ("wrote to scratchmem: %h=%h", adr_i, dat_i);
                /*
                if (adr_i[14:3]==15'h3e9 && dat_i==64'h00) begin
                  $display("3e9=00");
                  $finish;
                end
                */
        end
        
genvar g;
generate begin : gRom
for (g = 0; g < 1; g = g + 1)
always @(posedge clk_i)
        if (csd && wed)
                rommem[adrd[13:0]][g*12+11:g*12] <= datid[11:0];
end
endgenerate

wire pe_cs;
edge_det u1(.rst(rst_i), .clk(clk_i), .ce(1'b1), .i(cs), .pe(pe_cs), .ne(), .ee() );

reg [13:0] ctr;
always @(posedge clk_i)
if (rst_i) begin
        cnt <= 3'd0;
        ctr <= 14'd0;
end
else begin
        if (pe_cs) begin
                if (cti_i==3'b000)
                        ctr <= adr_i[13:0];
                else
                        ctr <= adr_i[13:0] + 12'd1;
                cnt <= 3'b000;
        end
        else if (cs && cnt[2:0]!=3'b100 && cti_i!=3'b000) begin
                ctr <= ctr + 2'd1;
                cnt <= cnt + 3'd1;
        end
end

always @(posedge clk_i)
        radr <= pe_cs ? adr_i[13:0] : ctr;

reg [13:0] spr;
always @(posedge clk_i)
        spr <= sp[13:0];

always @(posedge clk_i)
if (rst_i)
        datod <= 12'h00;
else begin
        datod <= rommem[radr[13:0]];
        if (!we_i & cs)
                $display("read from scratchmem: %h=%h", radr, rommem[radr[13:0]]);
//      $display("-------------- Stack --------------");
//      for (n = -6; n < 8; n = n + 1) begin
//              $display("%c%c %h %h", n==0 ? "-": " ", n==0 ?">" : " ",spr + n, rommem[spr+n]);
//      end
end

always @(posedge clk_i)
if (rst_i)
        dat_o <= 'h00;
else begin
        if (cs_i)
                dat_o <= datod;
        else
                dat_o <= 'd0;
end

endmodule