458 lines
16 KiB
Systemverilog
458 lines
16 KiB
Systemverilog
// Copyright © 2019-2023
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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`include "VX_platform.vh"
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`TRACING_OFF
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module VX_rr_arbiter #(
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parameter NUM_REQS = 1,
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parameter LOCK_ENABLE = 0,
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parameter MODEL = 1,
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parameter LOG_NUM_REQS = `LOG2UP(NUM_REQS)
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) (
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input wire clk,
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input wire reset,
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input wire [NUM_REQS-1:0] requests,
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output wire [LOG_NUM_REQS-1:0] grant_index,
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output wire [NUM_REQS-1:0] grant_onehot,
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output wire grant_valid,
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input wire grant_unlock
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);
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if (NUM_REQS == 1) begin
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`UNUSED_VAR (clk)
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`UNUSED_VAR (reset)
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`UNUSED_VAR (grant_unlock)
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assign grant_index = '0;
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assign grant_onehot = requests;
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assign grant_valid = requests[0];
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end else if (NUM_REQS == 2) begin
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reg [LOG_NUM_REQS-1:0] grant_index_r;
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reg [NUM_REQS-1:0] grant_onehot_r;
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reg [LOG_NUM_REQS-1:0] state;
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always @(*) begin
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casez ({state, requests})
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3'b0_01,
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3'b1_?1: begin grant_onehot_r = 2'b01; grant_index_r = LOG_NUM_REQS'(0); end
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default: begin grant_onehot_r = 2'b10; grant_index_r = LOG_NUM_REQS'(1); end
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endcase
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end
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always @(posedge clk) begin
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if (reset) begin
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state <= '0;
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end else if (!LOCK_ENABLE || grant_unlock) begin
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state <= grant_index_r;
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end
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end
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assign grant_index = grant_index_r;
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assign grant_onehot = grant_onehot_r;
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assign grant_valid = (| requests);
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end /*else if (NUM_REQS == 3) begin
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reg [LOG_NUM_REQS-1:0] grant_index_r;
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reg [NUM_REQS-1:0] grant_onehot_r;
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reg [LOG_NUM_REQS-1:0] state;
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always @(*) begin
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casez ({state, requests})
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5'b00_001,
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5'b01_0?1,
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5'b10_??1: begin grant_onehot_r = 3'b001; grant_index_r = LOG_NUM_REQS'(0); end
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5'b00_?1?,
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5'b01_010,
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5'b10_?10: begin grant_onehot_r = 3'b010; grant_index_r = LOG_NUM_REQS'(1); end
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default: begin grant_onehot_r = 3'b100; grant_index_r = LOG_NUM_REQS'(2); end
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endcase
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end
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always @(posedge clk) begin
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if (reset) begin
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state <= '0;
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end else if (!LOCK_ENABLE || grant_unlock) begin
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state <= grant_index_r;
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end
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end
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assign grant_index = grant_index_r;
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assign grant_onehot = grant_onehot_r;
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assign grant_valid = (| requests);
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end */else if (NUM_REQS == 4) begin
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reg [LOG_NUM_REQS-1:0] grant_index_r;
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reg [NUM_REQS-1:0] grant_onehot_r;
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reg [LOG_NUM_REQS-1:0] state;
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always @(*) begin
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casez ({state, requests})
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6'b00_0001,
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6'b01_00?1,
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6'b10_0??1,
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6'b11_???1: begin grant_onehot_r = 4'b0001; grant_index_r = LOG_NUM_REQS'(0); end
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6'b00_??1?,
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6'b01_0010,
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6'b10_0?10,
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6'b11_??10: begin grant_onehot_r = 4'b0010; grant_index_r = LOG_NUM_REQS'(1); end
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6'b00_?10?,
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6'b01_?1??,
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6'b10_0100,
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6'b11_?100: begin grant_onehot_r = 4'b0100; grant_index_r = LOG_NUM_REQS'(2); end
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default: begin grant_onehot_r = 4'b1000; grant_index_r = LOG_NUM_REQS'(3); end
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endcase
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end
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always @(posedge clk) begin
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if (reset) begin
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state <= '0;
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end else if (!LOCK_ENABLE || grant_unlock) begin
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state <= grant_index_r;
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end
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end
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assign grant_index = grant_index_r;
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assign grant_onehot = grant_onehot_r;
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assign grant_valid = (| requests);
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end /*else if (NUM_REQS == 5) begin
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reg [LOG_NUM_REQS-1:0] grant_index_r;
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reg [NUM_REQS-1:0] grant_onehot_r;
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reg [LOG_NUM_REQS-1:0] state;
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always @(*) begin
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casez ({state, requests})
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8'b000_00001,
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8'b001_000?1,
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8'b010_00??1,
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8'b011_0???1,
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8'b100_????1: begin grant_onehot_r = 5'b00001; grant_index_r = LOG_NUM_REQS'(0); end
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8'b000_???1?,
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8'b001_00010,
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8'b010_00?10,
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8'b011_0??10,
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8'b100_???10: begin grant_onehot_r = 5'b00010; grant_index_r = LOG_NUM_REQS'(1); end
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8'b000_??10?,
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8'b001_??1??,
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8'b010_00100,
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8'b011_0?100,
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8'b100_??100: begin grant_onehot_r = 5'b00100; grant_index_r = LOG_NUM_REQS'(2); end
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8'b000_?100?,
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8'b001_?10??,
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8'b010_?1???,
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8'b011_01000,
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8'b100_?1000: begin grant_onehot_r = 5'b01000; grant_index_r = LOG_NUM_REQS'(3); end
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default: begin grant_onehot_r = 5'b10000; grant_index_r = LOG_NUM_REQS'(4); end
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endcase
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end
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always @(posedge clk) begin
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if (reset) begin
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state <= '0;
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end else if (!LOCK_ENABLE || grant_unlock) begin
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state <= grant_index_r;
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end
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end
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assign grant_index = grant_index_r;
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assign grant_onehot = grant_onehot_r;
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assign grant_valid = (| requests);
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end else if (NUM_REQS == 6) begin
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reg [LOG_NUM_REQS-1:0] grant_index_r;
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reg [NUM_REQS-1:0] grant_onehot_r;
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reg [LOG_NUM_REQS-1:0] state;
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always @(*) begin
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casez ({state, requests})
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9'b000_000001,
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9'b001_0000?1,
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9'b010_000??1,
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9'b011_00???1,
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9'b100_0????1,
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9'b101_?????1: begin grant_onehot_r = 6'b000001; grant_index_r = LOG_NUM_REQS'(0); end
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9'b000_????1?,
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9'b001_000010,
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9'b010_000?10,
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9'b011_00??10,
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9'b100_0???10,
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9'b101_????10: begin grant_onehot_r = 6'b000010; grant_index_r = LOG_NUM_REQS'(1); end
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9'b000_???10?,
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9'b001_???1??,
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9'b010_000100,
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9'b011_00?100,
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9'b100_0??100,
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9'b101_???100: begin grant_onehot_r = 6'b000100; grant_index_r = LOG_NUM_REQS'(2); end
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9'b000_??100?,
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9'b001_??10??,
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9'b010_??1???,
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9'b011_001000,
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9'b100_0?1000,
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9'b101_??1000: begin grant_onehot_r = 6'b001000; grant_index_r = LOG_NUM_REQS'(3); end
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9'b000_?1000?,
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9'b001_?100??,
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9'b010_?10???,
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9'b011_?1????,
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9'b100_010000,
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9'b101_?10000: begin grant_onehot_r = 6'b010000; grant_index_r = LOG_NUM_REQS'(4); end
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default: begin grant_onehot_r = 6'b100000; grant_index_r = LOG_NUM_REQS'(5); end
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endcase
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end
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always @(posedge clk) begin
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if (reset) begin
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state <= '0;
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end else if (!LOCK_ENABLE || grant_unlock) begin
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state <= grant_index_r;
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end
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end
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assign grant_index = grant_index_r;
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assign grant_onehot = grant_onehot_r;
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assign grant_valid = (| requests);
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end else if (NUM_REQS == 7) begin
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reg [LOG_NUM_REQS-1:0] grant_index_r;
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reg [NUM_REQS-1:0] grant_onehot_r;
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reg [LOG_NUM_REQS-1:0] state;
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always @(*) begin
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casez ({state, requests})
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10'b000_000001,
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10'b001_0000?1,
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10'b010_000??1,
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10'b011_00???1,
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10'b100_00???1,
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10'b101_0????1,
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10'b110_?????1: begin grant_onehot_r = 7'b0000001; grant_index_r = LOG_NUM_REQS'(0); end
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10'b000_?????1?,
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10'b001_0000010,
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10'b010_0000?10,
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10'b011_000??10,
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10'b100_00???10,
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10'b101_0????10,
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10'b110_?????10: begin grant_onehot_r = 7'b0000010; grant_index_r = LOG_NUM_REQS'(1); end
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10'b000_????10?,
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10'b001_????1??,
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10'b010_0000100,
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10'b011_000?100,
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10'b100_00??100,
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10'b101_0???100,
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10'b110_????100: begin grant_onehot_r = 7'b0000100; grant_index_r = LOG_NUM_REQS'(2); end
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10'b000_???100?,
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10'b001_???10??,
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10'b010_???1???,
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10'b011_0001000,
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10'b100_00?1000,
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10'b101_0??1000,
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10'b110_???1000: begin grant_onehot_r = 7'b0001000; grant_index_r = LOG_NUM_REQS'(3); end
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10'b000_??1000?,
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10'b001_??100??,
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10'b010_??10???,
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10'b011_??1????,
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10'b100_0010000,
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10'b101_0?10000,
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10'b110_??10000: begin grant_onehot_r = 7'b0010000; grant_index_r = LOG_NUM_REQS'(4); end
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10'b000_?10000?,
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10'b001_?1000??,
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10'b010_?100???,
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10'b011_?10????,
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10'b100_?1?????,
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10'b101_0100000,
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10'b110_?100000: begin grant_onehot_r = 7'b0100000; grant_index_r = LOG_NUM_REQS'(5); end
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default: begin grant_onehot_r = 7'b1000000; grant_index_r = LOG_NUM_REQS'(6); end
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endcase
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end
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always @(posedge clk) begin
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if (reset) begin
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state <= '0;
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end else if (!LOCK_ENABLE || grant_unlock) begin
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state <= grant_index_r;
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end
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end
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assign grant_index = grant_index_r;
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assign grant_onehot = grant_onehot_r;
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assign grant_valid = (| requests);
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end */else if (NUM_REQS == 8) begin
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reg [LOG_NUM_REQS-1:0] grant_index_r;
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reg [NUM_REQS-1:0] grant_onehot_r;
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reg [LOG_NUM_REQS-1:0] state;
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always @(*) begin
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casez ({state, requests})
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11'b000_00000001,
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11'b001_000000?1,
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11'b010_00000??1,
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11'b011_0000???1,
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11'b100_000????1,
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11'b101_00?????1,
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11'b110_0??????1,
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11'b111_???????1: begin grant_onehot_r = 8'b00000001; grant_index_r = LOG_NUM_REQS'(0); end
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11'b000_??????1?,
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11'b001_00000010,
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11'b010_00000?10,
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11'b011_0000??10,
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11'b100_000???10,
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11'b101_00????10,
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11'b110_0?????10,
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11'b111_??????10: begin grant_onehot_r = 8'b00000010; grant_index_r = LOG_NUM_REQS'(1); end
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11'b000_?????10?,
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11'b001_?????1??,
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11'b010_00000100,
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11'b011_0000?100,
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11'b100_000??100,
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11'b101_00???100,
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11'b110_0????100,
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11'b111_?????100: begin grant_onehot_r = 8'b00000100; grant_index_r = LOG_NUM_REQS'(2); end
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11'b000_????100?,
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11'b001_????10??,
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11'b010_????1???,
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11'b011_00001000,
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11'b100_000?1000,
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11'b101_00??1000,
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11'b110_0???1000,
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11'b111_????1000: begin grant_onehot_r = 8'b00001000; grant_index_r = LOG_NUM_REQS'(3); end
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11'b000_???1000?,
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11'b001_???100??,
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11'b010_???10???,
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11'b011_???1????,
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11'b100_00010000,
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11'b101_00?10000,
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11'b110_0??10000,
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11'b111_???10000: begin grant_onehot_r = 8'b00010000; grant_index_r = LOG_NUM_REQS'(4); end
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11'b000_??10000?,
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11'b001_??1000??,
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11'b010_??100???,
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11'b011_??10????,
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11'b100_??1?????,
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11'b101_00100000,
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11'b110_0?100000,
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11'b111_??100000: begin grant_onehot_r = 8'b00100000; grant_index_r = LOG_NUM_REQS'(5); end
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11'b000_?100000?,
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11'b001_?10000??,
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11'b010_?1000???,
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11'b011_?100????,
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11'b100_?10?????,
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11'b101_?1??????,
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11'b110_01000000,
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11'b111_?1000000: begin grant_onehot_r = 8'b01000000; grant_index_r = LOG_NUM_REQS'(6); end
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default: begin grant_onehot_r = 8'b10000000; grant_index_r = LOG_NUM_REQS'(7); end
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endcase
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end
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always @(posedge clk) begin
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if (reset) begin
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state <= '0;
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end else if (!LOCK_ENABLE || grant_unlock) begin
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state <= grant_index_r;
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end
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end
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assign grant_index = grant_index_r;
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assign grant_onehot = grant_onehot_r;
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assign grant_valid = (| requests);
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end else if (MODEL == 1) begin
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`IGNORE_UNOPTFLAT_BEGIN
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wire [NUM_REQS-1:0] mask_higher_pri_regs, unmask_higher_pri_regs;
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`IGNORE_UNOPTFLAT_END
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wire [NUM_REQS-1:0] grant_masked, grant_unmasked;
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reg [NUM_REQS-1:0] pointer_reg;
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wire [NUM_REQS-1:0] req_masked = requests & pointer_reg;
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assign mask_higher_pri_regs[NUM_REQS-1:1] = mask_higher_pri_regs[NUM_REQS-2:0] | req_masked[NUM_REQS-2:0];
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assign mask_higher_pri_regs[0] = 1'b0;
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assign grant_masked[NUM_REQS-1:0] = req_masked[NUM_REQS-1:0] & ~mask_higher_pri_regs[NUM_REQS-1:0];
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assign unmask_higher_pri_regs[NUM_REQS-1:1] = unmask_higher_pri_regs[NUM_REQS-2:0] | requests[NUM_REQS-2:0];
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assign unmask_higher_pri_regs[0] = 1'b0;
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assign grant_unmasked[NUM_REQS-1:0] = requests[NUM_REQS-1:0] & ~unmask_higher_pri_regs[NUM_REQS-1:0];
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wire no_req_masked = ~(|req_masked);
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assign grant_onehot = ({NUM_REQS{no_req_masked}} & grant_unmasked) | grant_masked;
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always @(posedge clk) begin
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if (reset) begin
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pointer_reg <= {NUM_REQS{1'b1}};
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end else if (!LOCK_ENABLE || grant_unlock) begin
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if (|req_masked) begin
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pointer_reg <= mask_higher_pri_regs;
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end else if (|requests) begin
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pointer_reg <= unmask_higher_pri_regs;
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end else begin
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pointer_reg <= pointer_reg;
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end
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end
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end
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assign grant_valid = (| requests);
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VX_onehot_encoder #(
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.N (NUM_REQS)
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) onehot_encoder (
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.data_in (grant_onehot),
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.data_out (grant_index),
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`UNUSED_PIN (valid_out)
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);
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end else begin
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reg [LOG_NUM_REQS-1:0] grant_index_r;
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reg [NUM_REQS-1:0] grant_onehot_r;
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reg [NUM_REQS-1:0] state;
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always @(*) begin
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grant_index_r = 'x;
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grant_onehot_r = 'x;
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for (integer i = 0; i < NUM_REQS; ++i) begin
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for (integer j = 0; j < NUM_REQS; ++j) begin
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if (state[i] && requests[(j + 1) % NUM_REQS]) begin
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grant_index_r = LOG_NUM_REQS'((j + 1) % NUM_REQS);
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grant_onehot_r = '0;
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grant_onehot_r[(j + 1) % NUM_REQS] = 1;
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end
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end
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end
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end
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always @(posedge clk) begin
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if (reset) begin
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state <= '0;
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end else if (!LOCK_ENABLE || grant_unlock) begin
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state <= grant_index_r;
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end
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end
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|
|
|
assign grant_index = grant_index_r;
|
|
assign grant_onehot = grant_onehot_r;
|
|
assign grant_valid = (| requests);
|
|
end
|
|
|
|
endmodule
|
|
`TRACING_ON
|