mirror of
https://github.com/UzixLS/TSConf_MiST.git
synced 2025-07-19 07:11:22 +03:00
111 lines
3.2 KiB
Verilog
111 lines
3.2 KiB
Verilog
/* This file is part of JT12.
|
|
|
|
JT12 is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
JT12 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 General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with JT12. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
Author: Jose Tejada Gomez. Twitter: @topapate
|
|
Version: 1.0
|
|
Date: 29-10-2018
|
|
|
|
*/
|
|
|
|
module jt12_eg_step(
|
|
input attack,
|
|
input [ 4:0] base_rate,
|
|
input [ 4:0] keycode,
|
|
input [14:0] eg_cnt,
|
|
input cnt_in,
|
|
input [ 1:0] ks,
|
|
output cnt_lsb,
|
|
output reg step,
|
|
output reg [5:0] rate,
|
|
output reg sum_up
|
|
);
|
|
|
|
reg [6:0] pre_rate;
|
|
|
|
always @(*) begin : pre_rate_calc
|
|
if( base_rate == 5'd0 )
|
|
pre_rate = 7'd0;
|
|
else
|
|
case( ks )
|
|
2'd3: pre_rate = { base_rate, 1'b0 } + { 1'b0, keycode };
|
|
2'd2: pre_rate = { base_rate, 1'b0 } + { 2'b0, keycode[4:1] };
|
|
2'd1: pre_rate = { base_rate, 1'b0 } + { 3'b0, keycode[4:2] };
|
|
2'd0: pre_rate = { base_rate, 1'b0 } + { 4'b0, keycode[4:3] };
|
|
endcase
|
|
end
|
|
|
|
always @(*)
|
|
rate = pre_rate[6] ? 6'd63 : pre_rate[5:0];
|
|
|
|
reg [2:0] cnt;
|
|
|
|
reg [4:0] mux_sel;
|
|
always @(*) begin
|
|
mux_sel = attack ? (rate[5:2]+4'd1): {1'b0,rate[5:2]};
|
|
end // always @(*)
|
|
|
|
always @(*)
|
|
case( mux_sel )
|
|
5'h0: cnt = eg_cnt[14:12];
|
|
5'h1: cnt = eg_cnt[13:11];
|
|
5'h2: cnt = eg_cnt[12:10];
|
|
5'h3: cnt = eg_cnt[11: 9];
|
|
5'h4: cnt = eg_cnt[10: 8];
|
|
5'h5: cnt = eg_cnt[ 9: 7];
|
|
5'h6: cnt = eg_cnt[ 8: 6];
|
|
5'h7: cnt = eg_cnt[ 7: 5];
|
|
5'h8: cnt = eg_cnt[ 6: 4];
|
|
5'h9: cnt = eg_cnt[ 5: 3];
|
|
5'ha: cnt = eg_cnt[ 4: 2];
|
|
5'hb: cnt = eg_cnt[ 3: 1];
|
|
default: cnt = eg_cnt[ 2: 0];
|
|
endcase
|
|
|
|
////////////////////////////////
|
|
reg [7:0] step_idx;
|
|
|
|
always @(*) begin : rate_step
|
|
if( rate[5:4]==2'b11 ) begin // 0 means 1x, 1 means 2x
|
|
if( rate[5:2]==4'hf && attack)
|
|
step_idx = 8'b11111111; // Maximum attack speed, rates 60&61
|
|
else
|
|
case( rate[1:0] )
|
|
2'd0: step_idx = 8'b00000000;
|
|
2'd1: step_idx = 8'b10001000; // 2
|
|
2'd2: step_idx = 8'b10101010; // 4
|
|
2'd3: step_idx = 8'b11101110; // 6
|
|
endcase
|
|
end
|
|
else begin
|
|
if( rate[5:2]==4'd0 && !attack)
|
|
step_idx = 8'b11111110; // limit slowest decay rate
|
|
else
|
|
case( rate[1:0] )
|
|
2'd0: step_idx = 8'b10101010; // 4
|
|
2'd1: step_idx = 8'b11101010; // 5
|
|
2'd2: step_idx = 8'b11101110; // 6
|
|
2'd3: step_idx = 8'b11111110; // 7
|
|
endcase
|
|
end
|
|
// a rate of zero keeps the level still
|
|
step = rate[5:1]==5'd0 ? 1'b0 : step_idx[ cnt ];
|
|
end
|
|
|
|
assign cnt_lsb = cnt[0];
|
|
always @(*) begin
|
|
sum_up = cnt[0] != cnt_in;
|
|
end
|
|
|
|
endmodule // eg_step
|