119 lines
5.2 KiB
Systemverilog
119 lines
5.2 KiB
Systemverilog
// SPDX-License-Identifier: Apache-2.0
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// Copyright 2019 Western Digital Corporation or its affiliates.
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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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//
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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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module exu_mul_ctl
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import swerv_types::*;
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(
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input logic clk, // Top level clock
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input logic active_clk, // Level 1 active clock
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input logic clk_override, // Override clock enables
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input logic rst_l, // Reset
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input logic scan_mode, // Scan mode
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input logic [31:0] a, // A operand
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input logic [31:0] b, // B operand
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input logic [31:0] lsu_result_dc3, // Load result used in E1 bypass
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input logic freeze, // Pipeline freeze
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input mul_pkt_t mp, // valid, rs1_sign, rs2_sign, low, load_mul_rs1_bypass_e1, load_mul_rs2_bypass_e1
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output logic [31:0] out // Result
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);
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logic valid_e1, valid_e2;
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logic mul_c1_e1_clken, mul_c1_e2_clken, mul_c1_e3_clken;
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logic exu_mul_c1_e1_clk, exu_mul_c1_e2_clk, exu_mul_c1_e3_clk;
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logic [31:0] a_ff_e1, a_e1;
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logic [31:0] b_ff_e1, b_e1;
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logic load_mul_rs1_bypass_e1, load_mul_rs2_bypass_e1;
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logic rs1_sign_e1, rs1_neg_e1;
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logic rs2_sign_e1, rs2_neg_e1;
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logic signed [32:0] a_ff_e2, b_ff_e2;
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logic [63:0] prod_e3;
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logic low_e1, low_e2, low_e3;
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// --------------------------- Clock gating ----------------------------------
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// C1 clock enables
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assign mul_c1_e1_clken = (mp.valid | clk_override) & ~freeze;
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assign mul_c1_e2_clken = (valid_e1 | clk_override) & ~freeze;
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assign mul_c1_e3_clken = (valid_e2 | clk_override) & ~freeze;
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// C1 - 1 clock pulse for data
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rvclkhdr exu_mul_c1e1_cgc (.*, .en(mul_c1_e1_clken), .l1clk(exu_mul_c1_e1_clk));
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rvclkhdr exu_mul_c1e2_cgc (.*, .en(mul_c1_e2_clken), .l1clk(exu_mul_c1_e2_clk));
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rvclkhdr exu_mul_c1e3_cgc (.*, .en(mul_c1_e3_clken), .l1clk(exu_mul_c1_e3_clk));
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// --------------------------- Input flops ----------------------------------
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rvdffs #(1) valid_e1_ff (.*, .din(mp.valid), .dout(valid_e1), .clk(active_clk), .en(~freeze));
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rvdff #(1) rs1_sign_e1_ff (.*, .din(mp.rs1_sign), .dout(rs1_sign_e1), .clk(exu_mul_c1_e1_clk));
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rvdff #(1) rs2_sign_e1_ff (.*, .din(mp.rs2_sign), .dout(rs2_sign_e1), .clk(exu_mul_c1_e1_clk));
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rvdff #(1) low_e1_ff (.*, .din(mp.low), .dout(low_e1), .clk(exu_mul_c1_e1_clk));
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rvdff #(1) ld_rs1_byp_e1_ff (.*, .din(mp.load_mul_rs1_bypass_e1), .dout(load_mul_rs1_bypass_e1), .clk(exu_mul_c1_e1_clk));
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rvdff #(1) ld_rs2_byp_e1_ff (.*, .din(mp.load_mul_rs2_bypass_e1), .dout(load_mul_rs2_bypass_e1), .clk(exu_mul_c1_e1_clk));
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rvdffe #(32) a_e1_ff (.*, .din(a[31:0]), .dout(a_ff_e1[31:0]), .en(mul_c1_e1_clken));
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rvdffe #(32) b_e1_ff (.*, .din(b[31:0]), .dout(b_ff_e1[31:0]), .en(mul_c1_e1_clken));
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// --------------------------- E1 Logic Stage ----------------------------------
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assign a_e1[31:0] = (load_mul_rs1_bypass_e1) ? lsu_result_dc3[31:0] : a_ff_e1[31:0];
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assign b_e1[31:0] = (load_mul_rs2_bypass_e1) ? lsu_result_dc3[31:0] : b_ff_e1[31:0];
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assign rs1_neg_e1 = rs1_sign_e1 & a_e1[31];
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assign rs2_neg_e1 = rs2_sign_e1 & b_e1[31];
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rvdffs #(1) valid_e2_ff (.*, .din(valid_e1), .dout(valid_e2), .clk(active_clk), .en(~freeze));
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rvdff #(1) low_e2_ff (.*, .din(low_e1), .dout(low_e2), .clk(exu_mul_c1_e2_clk));
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rvdffe #(33) a_e2_ff (.*, .din({rs1_neg_e1, a_e1[31:0]}), .dout(a_ff_e2[32:0]), .en(mul_c1_e2_clken));
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rvdffe #(33) b_e2_ff (.*, .din({rs2_neg_e1, b_e1[31:0]}), .dout(b_ff_e2[32:0]), .en(mul_c1_e2_clken));
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// ---------------------- E2 Logic Stage --------------------------
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logic signed [65:0] prod_e2;
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assign prod_e2[65:0] = a_ff_e2 * b_ff_e2;
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rvdff #(1) low_e3_ff (.*, .din(low_e2), .dout(low_e3), .clk(exu_mul_c1_e3_clk));
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rvdffe #(64) prod_e3_ff (.*, .din(prod_e2[63:0]), .dout(prod_e3[63:0]), .en(mul_c1_e3_clken));
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// ----------------------- E3 Logic Stage -------------------------
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assign out[31:0] = low_e3 ? prod_e3[31:0] : prod_e3[63:32];
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endmodule // exu_mul_ctl
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