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[/] [ao486/] [trunk/] [rtl/] [soc/] [pc_dma/] [pc_dma.v] - Blame information for rev 2

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1 2 alfik 
/*
2 
 * Copyright (c) 2014, Aleksander Osman
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions are met:
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 *
8 
 * * Redistributions of source code must retain the above copyright notice, this
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 *   list of conditions and the following disclaimer.
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 *
11 
 * * Redistributions in binary form must reproduce the above copyright notice,
12 
 *   this list of conditions and the following disclaimer in the documentation
13 
 *   and/or other materials provided with the distribution.
14 
 *
15 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 
 */
26 
 
27 
module pc_dma(
28 
    input               clk,
29 
    input               rst_n,
30 
 
31 
    //000h - 00Fh for slave DMA
32 
    input       [3:0]   slave_address,
33 
    input               slave_read,
34 
    output reg  [7:0]   slave_readdata,
35 
    input               slave_write,
36 
    input       [7:0]   slave_writedata,
37 
 
38 
    //080h - 08Fh for DMA page
39 
    input       [3:0]   page_address,
40 
    input               page_read,
41 
    output reg  [7:0]   page_readdata,
42 
    input               page_write,
43 
    input       [7:0]   page_writedata,
44 
 
45 
    //0C0h - 0DFh for master DMA
46 
    input       [4:0]   master_address,
47 
    input               master_read,
48 
    output reg  [7:0]   master_readdata,
49 
    input               master_write,
50 
    input       [7:0]   master_writedata,
51 
 
52 
    //master
53 
    output reg  [31:0]  avm_address,
54 
    input               avm_waitrequest,
55 
    output reg          avm_read,
56 
    input               avm_readdatavalid,
57 
    input       [7:0]   avm_readdata,
58 
    output reg          avm_write,
59 
    output reg  [7:0]   avm_writedata,
60 
 
61 
    //floppy 8-bit dma channel
62 
    input               dma_floppy_req,
63 
    output reg          dma_floppy_ack,
64 
    output reg          dma_floppy_terminal,
65 
    output reg  [7:0]   dma_floppy_readdata,
66 
    input       [7:0]   dma_floppy_writedata,
67 
 
68 
    //soundblaster 8-bit dma channel
69 
    input               dma_soundblaster_req,
70 
    output reg          dma_soundblaster_ack,
71 
    output reg          dma_soundblaster_terminal,
72 
    output reg  [7:0]   dma_soundblaster_readdata,
73 
    input       [7:0]   dma_soundblaster_writedata
74 
);
75 
 
76 
//------------------------------------------------------------------------------
77 
 
78 
`define SDRAM_BASE      32'h08000000
79 
 
80 
//------------------------------------------------------------------------------
81 
 
82 
reg slave_read_last;
83 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) slave_read_last <= 1'b0; else if(slave_read_last) slave_read_last <= 1'b0; else slave_read_last <= slave_read; end
84 
wire slave_read_valid = slave_read && slave_read_last == 1'b0;
85 
 
86 
//not needed: reg page_read_last;
87 
 
88 
reg master_read_last;
89 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) master_read_last <= 1'b0; else if(master_read_last) master_read_last <= 1'b0; else master_read_last <= master_read; end
90 
wire master_read_valid = master_read && master_read_last == 1'b0;
91 
 
92 
//------------------------------------------------------------------------------
93 
 
94 
wire pag_extra_0_address =
95 
    page_address == 4'h0 || page_address == 4'h4 || page_address == 4'h5 || page_address == 4'h6 ||
96 
    page_address == 4'h8 || page_address == 4'hC || page_address == 4'hD || page_address == 4'hE;
97 
 
98 
reg [7:0] pag_extra_0;
99 
always @(posedge clk or negedge rst_n) begin
100 
    if(rst_n == 1'b0)                           pag_extra_0 <= 8'd0;
101 
    else if(page_write && pag_extra_0_address)  pag_extra_0 <= page_writedata;
102 
end
103 
 
104 
wire [7:0] pag_readdata_prepared =
105 
    (page_address == 4'h1)?        sla_page_2 :
106 
    (page_address == 4'h2)?        sla_page_3 :
107 
    (page_address == 4'h3)?        sla_page_1 :
108 
    (page_address == 4'h7)?        sla_page_0 :
109 
    (page_address == 4'h9)?        mas_page_2 :
110 
    (page_address == 4'hA)?        mas_page_3 :
111 
    (page_address == 4'hB)?        mas_page_1 :
112 
    (page_address == 4'hF)?        mas_page_0 :
113 
                                   pag_extra_0;
114 
 
115 
always @(posedge clk or negedge rst_n) begin
116 
    if(rst_n == 1'b0)   page_readdata <= 8'd0;
117 
    else                page_readdata <= pag_readdata_prepared;
118 
end
119 
 
120 
//------------------------------------------------------------------------------
121 
 
122 
reg [7:0] sla_page_0;
123 
reg [7:0] sla_page_1;
124 
reg [7:0] sla_page_2;
125 
reg [7:0] sla_page_3;
126 
 
127 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_page_0 <= 8'd0; else if(page_write && page_address == 4'h7) sla_page_0 <= page_writedata; end
128 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_page_1 <= 8'd0; else if(page_write && page_address == 4'h3) sla_page_1 <= page_writedata; end
129 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_page_2 <= 8'd0; else if(page_write && page_address == 4'h1) sla_page_2 <= page_writedata; end
130 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_page_3 <= 8'd0; else if(page_write && page_address == 4'h2) sla_page_3 <= page_writedata; end
131 
 
132 
reg [7:0] mas_page_0;
133 
reg [7:0] mas_page_1;
134 
reg [7:0] mas_page_2;
135 
reg [7:0] mas_page_3;
136 
 
137 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) mas_page_0 <= 8'd0; else if(page_write && page_address == 4'hF) mas_page_0 <= page_writedata; end
138 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) mas_page_1 <= 8'd0; else if(page_write && page_address == 4'hB) mas_page_1 <= page_writedata; end
139 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) mas_page_2 <= 8'd0; else if(page_write && page_address == 4'h9) mas_page_2 <= page_writedata; end
140 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) mas_page_3 <= 8'd0; else if(page_write && page_address == 4'hA) mas_page_3 <= page_writedata; end
141 
 
142 
 
143 
//------------------------------------------------------------------------------
144 
 
145 
wire [7:0] sla_readdata_prepared =
146 
    (slave_address == 4'h0 && sla_flip_flop == 1'b0)?    sla_current_address_0[7:0] :
147 
    (slave_address == 4'h0 && sla_flip_flop == 1'b1)?    sla_current_address_0[15:8] :
148 
    (slave_address == 4'h2 && sla_flip_flop == 1'b0)?    sla_current_address_1[7:0] :
149 
    (slave_address == 4'h2 && sla_flip_flop == 1'b1)?    sla_current_address_1[15:8] :
150 
    (slave_address == 4'h4 && sla_flip_flop == 1'b0)?    sla_current_address_2[7:0] :
151 
    (slave_address == 4'h4 && sla_flip_flop == 1'b1)?    sla_current_address_2[15:8] :
152 
    (slave_address == 4'h6 && sla_flip_flop == 1'b0)?    sla_current_address_3[7:0] :
153 
    (slave_address == 4'h6 && sla_flip_flop == 1'b1)?    sla_current_address_3[15:8] :
154 
 
155 
    (slave_address == 4'h1 && sla_flip_flop == 1'b0)?    sla_current_counter_0[7:0] :
156 
    (slave_address == 4'h1 && sla_flip_flop == 1'b1)?    sla_current_counter_0[15:8] :
157 
    (slave_address == 4'h3 && sla_flip_flop == 1'b0)?    sla_current_counter_1[7:0] :
158 
    (slave_address == 4'h3 && sla_flip_flop == 1'b1)?    sla_current_counter_1[15:8] :
159 
    (slave_address == 4'h5 && sla_flip_flop == 1'b0)?    sla_current_counter_2[7:0] :
160 
    (slave_address == 4'h5 && sla_flip_flop == 1'b1)?    sla_current_counter_2[15:8] :
161 
    (slave_address == 4'h7 && sla_flip_flop == 1'b0)?    sla_current_counter_3[7:0] :
162 
    (slave_address == 4'h7 && sla_flip_flop == 1'b1)?    sla_current_counter_3[15:8] :
163 
 
164 
    (slave_address == 4'h8)?                            { sla_pending, sla_terminated } :
165 
 
166 
    (slave_address == 4'hF)?                            { 4'hF, sla_mask } :
167 
                                                        8'd0; //temp reg
168 
 
169 
always @(posedge clk or negedge rst_n) begin
170 
    if(rst_n == 1'b0)   slave_readdata <= 8'd0;
171 
    else                slave_readdata <= sla_readdata_prepared;
172 
end
173 
 
174 
wire sla_reset = slave_write && slave_address == 4'hD;
175 
 
176 
wire sla_flop_flop_flip = (slave_read_valid || slave_write) && (slave_address <= 4'h7);
177 
 
178 
reg sla_flip_flop;
179 
always @(posedge clk or negedge rst_n) begin
180 
    if(rst_n == 1'b0)                               sla_flip_flop <= 1'b0;
181 
    else if(sla_reset)                              sla_flip_flop <= 1'b0;
182 
    else if(slave_write && slave_address == 4'hC)   sla_flip_flop <= 1'b0;
183 
    else if(sla_flop_flop_flip)                     sla_flip_flop <= ~(sla_flip_flop);
184 
end
185 
 
186 
reg [15:0] sla_base_address_1;
187 
reg [15:0] sla_base_address_2;
188 
 
189 
always @(posedge clk or negedge rst_n) begin
190 
    if(rst_n == 1'b0) sla_base_address_1 <= 16'd0;
191 
    else if(slave_write && slave_address == 4'h2 && sla_flip_flop == 1'b0)  sla_base_address_1 <= { sla_base_address_1[15:8], slave_writedata };
192 
    else if(slave_write && slave_address == 4'h2 && sla_flip_flop == 1'b1)  sla_base_address_1 <= { slave_writedata, sla_base_address_1[7:0] };
193 
end
194 
always @(posedge clk or negedge rst_n) begin
195 
    if(rst_n == 1'b0) sla_base_address_2 <= 16'd0;
196 
    else if(slave_write && slave_address == 4'h4 && sla_flip_flop == 1'b0)  sla_base_address_2 <= { sla_base_address_2[15:8], slave_writedata };
197 
    else if(slave_write && slave_address == 4'h4 && sla_flip_flop == 1'b1)  sla_base_address_2 <= { slave_writedata, sla_base_address_2[7:0] };
198 
end
199 
 
200 
reg [15:0] sla_current_address_0;
201 
reg [15:0] sla_current_address_1;
202 
reg [15:0] sla_current_address_2;
203 
reg [15:0] sla_current_address_3;
204 
 
205 
always @(posedge clk or negedge rst_n) begin
206 
    if(rst_n == 1'b0) sla_current_address_0 <= 16'd0;
207 
    else if(slave_write && slave_address == 4'h0 && sla_flip_flop == 1'b0)  sla_current_address_0 <= { sla_current_address_0[15:8], slave_writedata };
208 
    else if(slave_write && slave_address == 4'h0 && sla_flip_flop == 1'b1)  sla_current_address_0 <= { slave_writedata, sla_current_address_0[7:0] };
209 
end
210 
always @(posedge clk or negedge rst_n) begin
211 
    if(rst_n == 1'b0) sla_current_address_1 <= 16'd0;
212 
    else if(slave_write && slave_address == 4'h2 && sla_flip_flop == 1'b0)  sla_current_address_1 <= { sla_current_address_1[15:8], slave_writedata };
213 
    else if(slave_write && slave_address == 4'h2 && sla_flip_flop == 1'b1)  sla_current_address_1 <= { slave_writedata, sla_current_address_1[7:0] };
214 
 
215 
    else if(dma_soundblaster_tc && sla_auto_1)         sla_current_address_1 <= sla_base_address_1;
216 
    else if(dma_soundblaster_update && ~(sla_decrement_1))                  sla_current_address_1 <= sla_current_address_1 + 16'd1;
217 
    else if(dma_soundblaster_update &&   sla_decrement_1)                   sla_current_address_1 <= sla_current_address_1 - 16'd1;
218 
end
219 
always @(posedge clk or negedge rst_n) begin
220 
    if(rst_n == 1'b0) sla_current_address_2 <= 16'd0;
221 
    else if(slave_write && slave_address == 4'h4 && sla_flip_flop == 1'b0)  sla_current_address_2 <= { sla_current_address_2[15:8], slave_writedata };
222 
    else if(slave_write && slave_address == 4'h4 && sla_flip_flop == 1'b1)  sla_current_address_2 <= { slave_writedata, sla_current_address_2[7:0] };
223 
 
224 
    else if(dma_floppy_tc && sla_auto_2)    sla_current_address_2 <= sla_base_address_2;
225 
 
226 
    else if(dma_floppy_update && ~(sla_decrement_2))                        sla_current_address_2 <= sla_current_address_2 + 16'd1;
227 
    else if(dma_floppy_update &&   sla_decrement_2)                         sla_current_address_2 <= sla_current_address_2 - 16'd1;
228 
end
229 
always @(posedge clk or negedge rst_n) begin
230 
    if(rst_n == 1'b0) sla_current_address_3 <= 16'd0;
231 
    else if(slave_write && slave_address == 4'h6 && sla_flip_flop == 1'b0)  sla_current_address_3 <= { sla_current_address_3[15:8], slave_writedata };
232 
    else if(slave_write && slave_address == 4'h6 && sla_flip_flop == 1'b1)  sla_current_address_3 <= { slave_writedata, sla_current_address_3[7:0] };
233 
end
234 
 
235 
reg [15:0] sla_base_counter_1;
236 
reg [15:0] sla_base_counter_2;
237 
 
238 
always @(posedge clk or negedge rst_n) begin
239 
    if(rst_n == 1'b0) sla_base_counter_1 <= 16'd0;
240 
    else if(slave_write && slave_address == 4'h3 && sla_flip_flop == 1'b0)  sla_base_counter_1 <= { sla_base_counter_1[15:8], slave_writedata };
241 
    else if(slave_write && slave_address == 4'h3 && sla_flip_flop == 1'b1)  sla_base_counter_1 <= { slave_writedata, sla_base_counter_1[7:0] };
242 
end
243 
always @(posedge clk or negedge rst_n) begin
244 
    if(rst_n == 1'b0) sla_base_counter_2 <= 16'd0;
245 
    else if(slave_write && slave_address == 4'h5 && sla_flip_flop == 1'b0)  sla_base_counter_2 <= { sla_base_counter_2[15:8], slave_writedata };
246 
    else if(slave_write && slave_address == 4'h5 && sla_flip_flop == 1'b1)  sla_base_counter_2 <= { slave_writedata, sla_base_counter_2[7:0] };
247 
end
248 
 
249 
reg [15:0] sla_current_counter_0;
250 
reg [15:0] sla_current_counter_1;
251 
reg [15:0] sla_current_counter_2;
252 
reg [15:0] sla_current_counter_3;
253 
 
254 
always @(posedge clk or negedge rst_n) begin
255 
    if(rst_n == 1'b0) sla_current_counter_0 <= 16'd0;
256 
    else if(slave_write && slave_address == 4'h1 && sla_flip_flop == 1'b0)  sla_current_counter_0 <= { sla_current_counter_0[15:8], slave_writedata };
257 
    else if(slave_write && slave_address == 4'h1 && sla_flip_flop == 1'b1)  sla_current_counter_0 <= { slave_writedata, sla_current_counter_0[7:0] };
258 
end
259 
always @(posedge clk or negedge rst_n) begin
260 
    if(rst_n == 1'b0) sla_current_counter_1 <= 16'd0;
261 
    else if(slave_write && slave_address == 4'h3 && sla_flip_flop == 1'b0)  sla_current_counter_1 <= { sla_current_counter_1[15:8], slave_writedata };
262 
    else if(slave_write && slave_address == 4'h3 && sla_flip_flop == 1'b1)  sla_current_counter_1 <= { slave_writedata, sla_current_counter_1[7:0] };
263 
 
264 
    else if(dma_soundblaster_tc && sla_auto_1)                              sla_current_counter_1 <= sla_base_counter_1;
265 
    else if(dma_soundblaster_update)                                        sla_current_counter_1 <= sla_current_counter_1 - 16'd1;
266 
end
267 
always @(posedge clk or negedge rst_n) begin
268 
    if(rst_n == 1'b0) sla_current_counter_2 <= 16'd0;
269 
    else if(slave_write && slave_address == 4'h5 && sla_flip_flop == 1'b0)  sla_current_counter_2 <= { sla_current_counter_2[15:8], slave_writedata };
270 
    else if(slave_write && slave_address == 4'h5 && sla_flip_flop == 1'b1)  sla_current_counter_2 <= { slave_writedata, sla_current_counter_2[7:0] };
271 
 
272 
    else if(dma_floppy_tc && sla_auto_2)    sla_current_counter_2 <= sla_base_counter_2;
273 
    else if(dma_floppy_update)                                              sla_current_counter_2 <= sla_current_counter_2 - 16'd1;
274 
end
275 
always @(posedge clk or negedge rst_n) begin
276 
    if(rst_n == 1'b0)   sla_current_counter_3 <= 16'd0;
277 
    else if(slave_write && slave_address == 4'h7 && sla_flip_flop == 1'b0)  sla_current_counter_3 <= { sla_current_counter_3[15:8], slave_writedata };
278 
    else if(slave_write && slave_address == 4'h7 && sla_flip_flop == 1'b1)  sla_current_counter_3 <= { slave_writedata, sla_current_counter_3[7:0] };
279 
end
280 
 
281 
reg sla_disabled;
282 
always @(posedge clk or negedge rst_n) begin
283 
    if(rst_n == 1'b0)   sla_disabled <= 1'b0;
284 
    else if(sla_reset)  sla_disabled <= 1'b0;
285 
    else if(slave_write && slave_address == 4'h8) sla_disabled <= slave_writedata[2];
286 
end
287 
 
288 
wire [3:0] sla_writedata_bits =
289 
    (slave_writedata[1:0] == 2'd0)?     4'b0001 :
290 
    (slave_writedata[1:0] == 2'd1)?     4'b0010 :
291 
    (slave_writedata[1:0] == 2'd2)?     4'b0100 :
292 
                                        4'b1000;
293 
 
294 
wire [3:0] sla_pending_next =
295 
    { sla_pending[3], dma_floppy_req | dma_floppy_state != 3'd0, dma_soundblaster_req | dma_soundblaster_state != 3'd0, sla_pending[0] };
296 
 
297 
reg [3:0] sla_pending;
298 
always @(posedge clk or negedge rst_n) begin
299 
    if(rst_n == 1'b0)   sla_pending <= 4'd0;
300 
    else if(sla_reset)  sla_pending <= 4'd0;
301 
    else if(slave_write && slave_address == 4'h9 && slave_writedata[2])     sla_pending <= sla_pending | sla_writedata_bits;
302 
    else if(slave_write && slave_address == 4'h9 && ~(slave_writedata[2]))  sla_pending <= sla_pending & ~(sla_writedata_bits);
303 
    else                                                                    sla_pending <= sla_pending_next;
304 
end
305 
 
306 
reg [3:0] sla_mask;
307 
always @(posedge clk or negedge rst_n) begin
308 
    if(rst_n == 1'b0)   sla_mask <= 4'hF;
309 
    else if(sla_reset)  sla_mask <= 4'hF;
310 
    else if(slave_write && slave_address == 4'hE)                           sla_mask <= 4'h0;
311 
    else if(slave_write && slave_address == 4'hF)                           sla_mask <= slave_writedata[3:0];
312 
    else if(slave_write && slave_address == 4'hA && slave_writedata[2])     sla_mask <= sla_mask | sla_writedata_bits;
313 
    else if(slave_write && slave_address == 4'hA && ~(slave_writedata[2]))  sla_mask <= sla_mask & ~(sla_writedata_bits);
314 
 
315 
    else if(dma_soundblaster_tc && ~(sla_auto_1))    sla_mask <= sla_mask | 4'b0010;
316 
    else if(dma_floppy_tc && ~(sla_auto_2))          sla_mask <= sla_mask | 4'b0100;
317 
end
318 
 
319 
reg sla_decrement_1;
320 
reg sla_decrement_2;
321 
 
322 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_decrement_1 <= 1'd0; else if(slave_write && slave_address == 4'hB && slave_writedata[1:0] == 2'd1) sla_decrement_1 <= slave_writedata[5]; end
323 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_decrement_2 <= 1'd0; else if(slave_write && slave_address == 4'hB && slave_writedata[1:0] == 2'd2) sla_decrement_2 <= slave_writedata[5]; end
324 
 
325 
reg sla_auto_1;
326 
reg sla_auto_2;
327 
 
328 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_auto_1 <= 1'd0; else if(slave_write && slave_address == 4'hB && slave_writedata[1:0] == 2'd1) sla_auto_1 <= slave_writedata[4]; end
329 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_auto_2 <= 1'd0; else if(slave_write && slave_address == 4'hB && slave_writedata[1:0] == 2'd2) sla_auto_2 <= slave_writedata[4]; end
330 
 
331 
reg [1:0] sla_transfer_1;
332 
reg [1:0] sla_transfer_2;
333 
 
334 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_transfer_1 <= 2'd0; else if(slave_write && slave_address == 4'hB && slave_writedata[1:0] == 2'd1) sla_transfer_1 <= slave_writedata[3:2]; end
335 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) sla_transfer_2 <= 2'd0; else if(slave_write && slave_address == 4'hB && slave_writedata[1:0] == 2'd2) sla_transfer_2 <= slave_writedata[3:2]; end
336 
 
337 
reg [3:0] sla_terminated;
338 
always @(posedge clk or negedge rst_n) begin
339 
    if(rst_n == 1'b0)                                   sla_terminated <= 4'h0;
340 
    else if(sla_reset)                                  sla_terminated <= 4'h0;
341 
    else if(slave_read_valid && slave_address == 4'h8)  sla_terminated <= 4'd0;
342 
    else if(dma_soundblaster_tc)                        sla_terminated <= sla_terminated | 4'b0010;
343 
    else if(dma_floppy_tc)                              sla_terminated <= sla_terminated | 4'b0100;
344 
end
345 
 
346 
//0: idle
347 
//1: prepare read avm (goto 2) or write avm (goto 6)
348 
 
349 
//2: read avm until ~(waitrequest); goto 3
350 
//3: read avm until readdatavalid; goto 4
351 
 
352 
//4: ack; update address; update counter (1 cycle); if tc goto 0
353 
//5: wait for dma_req; goto 1
354 
 
355 
//6: write avm unit ~(waitrequest); goto 4
356 
 
357 
//7: verify or illegal transfer type
358 
 
359 
wire dma_floppy_update = dma_floppy_state == 3'd4;
360 
wire dma_floppy_tc     = dma_floppy_update && sla_current_counter_2 == 16'h0000;
361 
 
362 
wire dma_soundblaster_update = dma_soundblaster_state == 3'd4;
363 
wire dma_soundblaster_tc     = dma_soundblaster_update && sla_current_counter_1 == 16'h0000;
364 
 
365 
wire dma_floppy_start       = sla_disabled == 1'b0 && dma_floppy_state == 3'd0 && dma_soundblaster_state == 3'd0 && sla_pending[2] && ~(sla_mask[2]) && (sla_pending[1] == 1'b0 || sla_mask[1]);
366 
wire dma_soundblaster_start = sla_disabled == 1'b0 && dma_floppy_state == 3'd0 && dma_soundblaster_state == 3'd0 && sla_pending[1] && ~(sla_mask[1]);
367 
 
368 
always @(posedge clk or negedge rst_n) begin
369 
    if(rst_n == 1'b0)                                   dma_floppy_terminal <= 1'b0;
370 
    else if(dma_floppy_state == 3'd4 && dma_floppy_tc)  dma_floppy_terminal <= 1'b1;
371 
    else                                                dma_floppy_terminal <= 1'b0;
372 
end
373 
always @(posedge clk or negedge rst_n) begin
374 
    if(rst_n == 1'b0)                                               dma_soundblaster_terminal <= 1'b0;
375 
    else if(dma_soundblaster_state == 3'd4 && dma_soundblaster_tc)  dma_soundblaster_terminal <= 1'b1;
376 
    else                                                            dma_soundblaster_terminal <= 1'b0;
377 
end
378 
 
379 
reg [2:0] dma_floppy_state;
380 
always @(posedge clk or negedge rst_n) begin
381 
    if(rst_n == 1'b0)   dma_floppy_state <= 3'd0;
382 
    else if(sla_reset)  dma_floppy_state <= 3'd0;
383 
 
384 
    else if(~(mas_not_ready) && dma_floppy_start)                   dma_floppy_state <= 3'd1;
385 
 
386 
    else if(dma_floppy_state == 3'd1 && sla_transfer_2 == 2'd2)     dma_floppy_state <= 3'd2; //read avm
387 
    else if(dma_floppy_state == 3'd2 && avm_waitrequest == 1'b0)    dma_floppy_state <= 3'd3;
388 
    else if(dma_floppy_state == 3'd3 && avm_readdatavalid)          dma_floppy_state <= 3'd4;
389 
 
390 
    else if(dma_floppy_state == 3'd4 && dma_floppy_tc)              dma_floppy_state <= 3'd0;
391 
    else if(dma_floppy_state == 3'd4 && ~(dma_floppy_tc))           dma_floppy_state <= 3'd5;
392 
    else if(dma_floppy_state == 3'd5 && dma_floppy_req)             dma_floppy_state <= 3'd1;
393 
 
394 
    else if(dma_floppy_state == 3'd1 && sla_transfer_2 == 2'd1)     dma_floppy_state <= 3'd6; //write avm
395 
    else if(dma_floppy_state == 3'd6 && avm_waitrequest == 1'b0)    dma_floppy_state <= 3'd4;
396 
 
397 
    else if(dma_floppy_state == 3'd1)                               dma_floppy_state <= 3'd7; //verify or illegal transfer type
398 
    else if(dma_floppy_state == 3'd7)                               dma_floppy_state <= 3'd4;
399 
end
400 
 
401 
reg [2:0] dma_soundblaster_state;
402 
always @(posedge clk or negedge rst_n) begin
403 
    if(rst_n == 1'b0)   dma_soundblaster_state <= 3'd0;
404 
    else if(sla_reset)  dma_soundblaster_state <= 3'd0;
405 
 
406 
    else if(~(mas_not_ready) && dma_soundblaster_start)                 dma_soundblaster_state <= 3'd1;
407 
 
408 
    else if(dma_soundblaster_state == 3'd1 && sla_transfer_1 == 2'd2)   dma_soundblaster_state <= 3'd2; //read avm
409 
    else if(dma_soundblaster_state == 3'd2 && avm_waitrequest == 1'b0)  dma_soundblaster_state <= 3'd3;
410 
    else if(dma_soundblaster_state == 3'd3 && avm_readdatavalid)        dma_soundblaster_state <= 3'd4;
411 
 
412 
    else if(dma_soundblaster_state == 3'd4 && dma_soundblaster_tc)      dma_soundblaster_state <= 3'd0;
413 
    else if(dma_soundblaster_state == 3'd4 && ~(dma_soundblaster_tc))   dma_soundblaster_state <= 3'd5;
414 
    else if(dma_soundblaster_state == 3'd5 && dma_soundblaster_req)     dma_soundblaster_state <= 3'd1;
415 
 
416 
    else if(dma_soundblaster_state == 3'd1 && sla_transfer_1 == 2'd1)   dma_soundblaster_state <= 3'd6; //write avm
417 
    else if(dma_soundblaster_state == 3'd6 && avm_waitrequest == 1'b0)  dma_soundblaster_state <= 3'd4;
418 
 
419 
    else if(dma_soundblaster_state == 3'd1)                             dma_soundblaster_state <= 3'd7; //verify or illegal transfer type
420 
    else if(dma_soundblaster_state == 3'd7)                             dma_soundblaster_state <= 3'd4;
421 
end
422 
 
423 
always @(posedge clk or negedge rst_n) begin
424 
    if(rst_n == 1'b0)                                           dma_floppy_ack <= 1'd0;
425 
     else if(dma_floppy_state == 3'd3 && avm_readdatavalid)     dma_floppy_ack <= 1'b1;
426 
     else if(dma_floppy_state == 3'd6 && ~(avm_waitrequest))    dma_floppy_ack <= 1'b1;
427 
     else if(dma_floppy_state == 3'd7)                          dma_floppy_ack <= 1'b1;
428 
     else                                                       dma_floppy_ack <= 1'b0;
429 
end
430 
 
431 
always @(posedge clk or negedge rst_n) begin
432 
    if(rst_n == 1'b0)                                               dma_soundblaster_ack <= 1'd0;
433 
    else if(dma_soundblaster_state == 3'd3 && avm_readdatavalid)    dma_soundblaster_ack <= 1'b1;
434 
    else if(dma_soundblaster_state == 3'd6 && ~(avm_waitrequest))   dma_soundblaster_ack <= 1'b1;
435 
    else if(dma_soundblaster_state == 3'd7)                         dma_soundblaster_ack <= 1'b1;
436 
    else                                                            dma_soundblaster_ack <= 1'b0;
437 
end
438 
 
439 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) dma_floppy_readdata       <= 8'd0; else if(avm_readdatavalid) dma_floppy_readdata       <= avm_readdata; end
440 
always @(posedge clk or negedge rst_n) begin if(rst_n == 1'b0) dma_soundblaster_readdata <= 8'd0; else if(avm_readdatavalid) dma_soundblaster_readdata <= avm_readdata; end
441 
 
442 
//------------------------------------------------------------------------------
443 
 
444 
always @(posedge clk or negedge rst_n) begin
445 
    if(rst_n == 1'b0)                       avm_address <= `SDRAM_BASE | 32'd0;
446 
    else if(dma_soundblaster_state == 3'd1) avm_address <= `SDRAM_BASE | { 8'd0, sla_page_1, sla_current_address_1 };
447 
    else if(dma_floppy_state == 3'd1)       avm_address <= `SDRAM_BASE | { 8'd0, sla_page_2, sla_current_address_2 };
448 
end
449 
 
450 
 
451 
always @(posedge clk or negedge rst_n) begin
452 
    if(rst_n == 1'b0)   avm_read <= 1'd0;
453 
 
454 
    else if(dma_soundblaster_state == 3'd1 && sla_transfer_1 == 2'd2)   avm_read <= 1'b1;
455 
    else if(dma_soundblaster_state == 3'd2 && avm_waitrequest == 1'b0)  avm_read <= 1'b0;
456 
 
457 
    else if(dma_floppy_state == 3'd1 && sla_transfer_2 == 2'd2)         avm_read <= 1'b1;
458 
    else if(dma_floppy_state == 3'd2 && avm_waitrequest == 1'b0)        avm_read <= 1'b0;
459 
end
460 
 
461 
always @(posedge clk or negedge rst_n) begin
462 
    if(rst_n == 1'b0)   avm_write <= 1'd0;
463 
 
464 
    else if(dma_soundblaster_state == 3'd1 && sla_transfer_1 == 2'd1)   avm_write <= 1'b1;
465 
    else if(dma_soundblaster_state == 3'd6 && avm_waitrequest == 1'b0)  avm_write <= 1'b0;
466 
 
467 
    else if(dma_floppy_state == 3'd1 && sla_transfer_2 == 2'd1)         avm_write <= 1'b1;
468 
    else if(dma_floppy_state == 3'd6 && avm_waitrequest == 1'b0)        avm_write <= 1'b0;
469 
end
470 
 
471 
always @(posedge clk or negedge rst_n) begin
472 
    if(rst_n == 1'b0)                                                   avm_writedata <= 8'd0;
473 
    else if(dma_soundblaster_state == 3'd1 && sla_transfer_1 == 2'd1)   avm_writedata <= dma_soundblaster_writedata;
474 
    else if(dma_floppy_state == 3'd1 && sla_transfer_2 == 2'd1)         avm_writedata <= dma_floppy_writedata;
475 
end
476 
 
477 
//------------------------------------------------------------------------------
478 
//------------------------------------------------------------------------------
479 
//------------------------------------------------------------------------------
480 
 
481 
wire [7:0] mas_readdata_prepared =
482 
    (master_address == 5'h00 && mas_flip_flop == 1'b0)?     mas_current_address_0[7:0] :
483 
    (master_address == 5'h00 && mas_flip_flop == 1'b1)?     mas_current_address_0[15:8] :
484 
    (master_address == 5'h04 && mas_flip_flop == 1'b0)?     mas_current_address_1[7:0] :
485 
    (master_address == 5'h04 && mas_flip_flop == 1'b1)?     mas_current_address_1[15:8] :
486 
    (master_address == 5'h08 && mas_flip_flop == 1'b0)?     mas_current_address_2[7:0] :
487 
    (master_address == 5'h08 && mas_flip_flop == 1'b1)?     mas_current_address_2[15:8] :
488 
    (master_address == 5'h0C && mas_flip_flop == 1'b0)?     mas_current_address_3[7:0] :
489 
    (master_address == 5'h0C && mas_flip_flop == 1'b1)?     mas_current_address_3[15:8] :
490 
 
491 
    (master_address == 5'h02 && mas_flip_flop == 1'b0)?     mas_current_counter_0[7:0] :
492 
    (master_address == 5'h02 && mas_flip_flop == 1'b1)?     mas_current_counter_0[15:8] :
493 
    (master_address == 5'h06 && mas_flip_flop == 1'b0)?     mas_current_counter_1[7:0] :
494 
    (master_address == 5'h06 && mas_flip_flop == 1'b1)?     mas_current_counter_1[15:8] :
495 
    (master_address == 5'h0A && mas_flip_flop == 1'b0)?     mas_current_counter_2[7:0] :
496 
    (master_address == 5'h0A && mas_flip_flop == 1'b1)?     mas_current_counter_2[15:8] :
497 
    (master_address == 5'h0E && mas_flip_flop == 1'b0)?     mas_current_counter_3[7:0] :
498 
    (master_address == 5'h0E && mas_flip_flop == 1'b1)?     mas_current_counter_3[15:8] :
499 
 
500 
    (master_address == 5'h10)?                              { mas_pending, 4'd0 } :
501 
 
502 
    (master_address == 5'h1E)?                              { 4'hF, mas_mask } :
503 
                                                            8'd0; //temp reg
504 
 
505 
always @(posedge clk or negedge rst_n) begin
506 
    if(rst_n == 1'b0)   master_readdata <= 8'd0;
507 
    else                master_readdata <= mas_readdata_prepared;
508 
end
509 
 
510 
wire mas_reset = master_write && master_address == 5'h1A;
511 
 
512 
wire mas_flop_flop_flip = (master_read_valid || master_write) && master_address[0] == 1'b0 && (master_address <= 5'h0E);
513 
 
514 
reg mas_flip_flop;
515 
always @(posedge clk or negedge rst_n) begin
516 
    if(rst_n == 1'b0)                                   mas_flip_flop <= 1'b0;
517 
    else if(mas_reset)                                  mas_flip_flop <= 1'b0;
518 
    else if(master_write && master_address == 5'h18)    mas_flip_flop <= 1'b0;
519 
    else if(mas_flop_flop_flip)                         mas_flip_flop <= ~(mas_flip_flop);
520 
end
521 
 
522 
reg [15:0] mas_current_address_0;
523 
reg [15:0] mas_current_address_1;
524 
reg [15:0] mas_current_address_2;
525 
reg [15:0] mas_current_address_3;
526 
 
527 
always @(posedge clk or negedge rst_n) begin
528 
    if(rst_n == 1'b0) mas_current_address_0 <= 16'd0;
529 
    else if(master_write && master_address == 5'h00 && mas_flip_flop == 1'b0)  mas_current_address_0 <= { mas_current_address_0[15:8], master_writedata };
530 
    else if(master_write && master_address == 5'h00 && mas_flip_flop == 1'b1)  mas_current_address_0 <= { master_writedata, mas_current_address_0[7:0] };
531 
end
532 
always @(posedge clk or negedge rst_n) begin
533 
    if(rst_n == 1'b0) mas_current_address_1 <= 16'd0;
534 
    else if(master_write && master_address == 5'h04 && mas_flip_flop == 1'b0)  mas_current_address_1 <= { mas_current_address_1[15:8], master_writedata };
535 
    else if(master_write && master_address == 5'h04 && mas_flip_flop == 1'b1)  mas_current_address_1 <= { master_writedata, mas_current_address_1[7:0] };
536 
end
537 
always @(posedge clk or negedge rst_n) begin
538 
    if(rst_n == 1'b0) mas_current_address_2 <= 16'd0;
539 
    else if(master_write && master_address == 5'h08 && mas_flip_flop == 1'b0)  mas_current_address_2 <= { mas_current_address_2[15:8], master_writedata };
540 
    else if(master_write && master_address == 5'h08 && mas_flip_flop == 1'b1)  mas_current_address_2 <= { master_writedata, mas_current_address_2[7:0] };
541 
end
542 
always @(posedge clk or negedge rst_n) begin
543 
    if(rst_n == 1'b0) mas_current_address_3 <= 16'd0;
544 
    else if(master_write && master_address == 5'h0C && mas_flip_flop == 1'b0)  mas_current_address_3 <= { mas_current_address_3[15:8], master_writedata };
545 
    else if(master_write && master_address == 5'h0C && mas_flip_flop == 1'b1)  mas_current_address_3 <= { master_writedata, mas_current_address_3[7:0] };
546 
end
547 
 
548 
reg [15:0] mas_current_counter_0;
549 
reg [15:0] mas_current_counter_1;
550 
reg [15:0] mas_current_counter_2;
551 
reg [15:0] mas_current_counter_3;
552 
 
553 
always @(posedge clk or negedge rst_n) begin
554 
    if(rst_n == 1'b0) mas_current_counter_0 <= 16'd0;
555 
    else if(master_write && master_address == 5'h02 && mas_flip_flop == 1'b0)  mas_current_counter_0 <= { mas_current_counter_0[15:8], master_writedata };
556 
    else if(master_write && master_address == 5'h02 && mas_flip_flop == 1'b1)  mas_current_counter_0 <= { master_writedata, mas_current_counter_0[7:0] };
557 
end
558 
always @(posedge clk or negedge rst_n) begin
559 
    if(rst_n == 1'b0) mas_current_counter_1 <= 16'd0;
560 
    else if(master_write && master_address == 5'h06 && mas_flip_flop == 1'b0)  mas_current_counter_1 <= { mas_current_counter_1[15:8], master_writedata };
561 
    else if(master_write && master_address == 5'h06 && mas_flip_flop == 1'b1)  mas_current_counter_1 <= { master_writedata, mas_current_counter_1[7:0] };
562 
end
563 
always @(posedge clk or negedge rst_n) begin
564 
    if(rst_n == 1'b0) mas_current_counter_2 <= 16'd0;
565 
    else if(master_write && master_address == 5'h0A && mas_flip_flop == 1'b0)  mas_current_counter_2 <= { mas_current_counter_2[15:8], master_writedata };
566 
    else if(master_write && master_address == 5'h0A && mas_flip_flop == 1'b1)  mas_current_counter_2 <= { master_writedata, mas_current_counter_2[7:0] };
567 
end
568 
always @(posedge clk or negedge rst_n) begin
569 
    if(rst_n == 1'b0)   mas_current_counter_3 <= 16'd0;
570 
    else if(master_write && master_address == 5'h0E && mas_flip_flop == 1'b0)  mas_current_counter_3 <= { mas_current_counter_3[15:8], master_writedata };
571 
    else if(master_write && master_address == 5'h0E && mas_flip_flop == 1'b1)  mas_current_counter_3 <= { master_writedata, mas_current_counter_3[7:0] };
572 
end
573 
 
574 
reg mas_disabled;
575 
always @(posedge clk or negedge rst_n) begin
576 
    if(rst_n == 1'b0)                                   mas_disabled <= 1'b0;
577 
    else if(mas_reset)                                  mas_disabled <= 1'b0;
578 
    else if(master_write && master_address == 5'h10)    mas_disabled <= master_writedata[2];
579 
end
580 
 
581 
wire [3:0] mas_writedata_bits =
582 
    (master_writedata[1:0] == 2'd0)?    4'b0001 :
583 
    (master_writedata[1:0] == 2'd1)?    4'b0010 :
584 
    (master_writedata[1:0] == 2'd2)?    4'b0100 :
585 
                                        4'b1000;
586 
 
587 
wire [3:0] mas_pending_next =
588 
    { mas_pending[3:1], dma_floppy_start || dma_soundblaster_start || dma_floppy_state != 3'd0 || dma_soundblaster_state != 3'd0 };
589 
 
590 
reg [3:0] mas_pending;
591 
always @(posedge clk or negedge rst_n) begin
592 
    if(rst_n == 1'b0)   mas_pending <= 4'd0;
593 
    else if(mas_reset)  mas_pending <= 4'd0;
594 
    else if(master_write && master_address == 5'h12 && master_writedata[2])     mas_pending <= mas_pending | mas_writedata_bits;
595 
    else if(master_write && master_address == 5'h12 && ~(master_writedata[2]))  mas_pending <= mas_pending & ~(mas_writedata_bits);
596 
    else                                                                        mas_pending <= mas_pending_next;
597 
end
598 
 
599 
reg [3:0] mas_mask;
600 
always @(posedge clk or negedge rst_n) begin
601 
    if(rst_n == 1'b0)   mas_mask <= 4'hF;
602 
    else if(mas_reset)  mas_mask <= 4'hF;
603 
    else if(master_write && master_address == 5'h1C)                            mas_mask <= 4'h0;
604 
    else if(master_write && master_address == 5'h1E)                            mas_mask <= master_writedata[3:0];
605 
    else if(master_write && master_address == 5'h14 && master_writedata[2])     mas_mask <= mas_mask | mas_writedata_bits;
606 
    else if(master_write && master_address == 5'h14 && ~(master_writedata[2]))  mas_mask <= mas_mask & ~(mas_writedata_bits);
607 
end
608 
 
609 
wire mas_not_ready = mas_disabled || mas_mask[0];
610 
 
611 
//------------------------------------------------------------------------------
612 
 
613 
// synthesis translate_off
614 
wire _unused_ok = &{ 1'b0, page_read, 1'b0 };
615 
// synthesis translate_on
616 
 
617 
//------------------------------------------------------------------------------
618 
 
619 
endmodule

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