577 lines
21 KiB
Systemverilog
577 lines
21 KiB
Systemverilog
// SPDX-License-Identifier: Apache-2.0
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// Copyright 2020 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 el2_exu_alu_ctl
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import el2_pkg::*;
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#(
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`include "el2_param.vh"
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)
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(
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input logic clk, // Top level clock
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input logic rst_l, // Reset
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input logic scan_mode, // Scan control
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input logic flush_upper_x, // Branch flush from previous cycle
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input logic flush_lower_r, // Master flush of entire pipeline
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input logic enable, // Clock enable
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input logic valid_in, // Valid
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input el2_alu_pkt_t ap, // predecodes
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input logic csr_ren_in, // CSR select
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input logic [31:0] csr_rddata_in, // CSR data
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input logic signed [31:0] a_in, // A operand
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input logic [31:0] b_in, // B operand
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input logic [31:1] pc_in, // for pc=pc+2,4 calculations
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input el2_predict_pkt_t pp_in, // Predicted branch structure
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input logic [12:1] brimm_in, // Branch offset
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output logic [31:0] result_ff, // final result
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output logic flush_upper_out, // Branch flush
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output logic flush_final_out, // Branch flush or flush entire pipeline
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output logic [31:1] flush_path_out, // Branch flush PC
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output logic [31:1] pc_ff, // flopped PC
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output logic pred_correct_out, // NPC control
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output el2_predict_pkt_t predict_p_out // Predicted branch structure
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);
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logic [31:0] zba_a_in;
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logic [31:0] aout;
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logic cout,ov,neg;
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logic [31:0] lout;
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logic [31:0] sout;
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logic sel_shift;
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logic sel_adder;
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logic slt_one;
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logic actual_taken;
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logic [31:1] pcout;
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logic cond_mispredict;
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logic target_mispredict;
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logic eq, ne, lt, ge;
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logic any_jal;
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logic [1:0] newhist;
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logic sel_pc;
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logic [31:0] csr_write_data;
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logic [31:0] result;
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// *** Start - BitManip ***
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// Zbb
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logic ap_clz;
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logic ap_ctz;
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logic ap_cpop;
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logic ap_sext_b;
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logic ap_sext_h;
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logic ap_min;
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logic ap_max;
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logic ap_rol;
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logic ap_ror;
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logic ap_rev8;
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logic ap_orc_b;
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logic ap_zbb;
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// Zbs
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logic ap_bset;
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logic ap_bclr;
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logic ap_binv;
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logic ap_bext;
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// Zbp
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logic ap_pack;
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logic ap_packu;
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logic ap_packh;
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// Zba
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logic ap_sh1add;
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logic ap_sh2add;
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logic ap_sh3add;
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logic ap_zba;
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if (pt.BITMANIP_ZBB == 1)
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begin
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assign ap_clz = ap.clz;
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assign ap_ctz = ap.ctz;
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assign ap_cpop = ap.cpop;
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assign ap_sext_b = ap.sext_b;
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assign ap_sext_h = ap.sext_h;
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assign ap_min = ap.min;
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assign ap_max = ap.max;
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end
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else
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begin
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assign ap_clz = 1'b0;
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assign ap_ctz = 1'b0;
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assign ap_cpop = 1'b0;
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assign ap_sext_b = 1'b0;
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assign ap_sext_h = 1'b0;
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assign ap_min = 1'b0;
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assign ap_max = 1'b0;
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end
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if ( (pt.BITMANIP_ZBB == 1) | (pt.BITMANIP_ZBP == 1) )
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begin
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assign ap_rol = ap.rol;
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assign ap_ror = ap.ror;
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assign ap_rev8 = ap.grev & (b_in[4:0] == 5'b11000);
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assign ap_orc_b = ap.gorc & (b_in[4:0] == 5'b00111);
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assign ap_zbb = ap.zbb;
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end
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else
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begin
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assign ap_rol = 1'b0;
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assign ap_ror = 1'b0;
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assign ap_rev8 = 1'b0;
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assign ap_orc_b = 1'b0;
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assign ap_zbb = 1'b0;
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end
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if (pt.BITMANIP_ZBS == 1)
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begin
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assign ap_bset = ap.bset;
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assign ap_bclr = ap.bclr;
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assign ap_binv = ap.binv;
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assign ap_bext = ap.bext;
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end
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else
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begin
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assign ap_bset = 1'b0;
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assign ap_bclr = 1'b0;
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assign ap_binv = 1'b0;
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assign ap_bext = 1'b0;
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end
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if (pt.BITMANIP_ZBP == 1)
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begin
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assign ap_packu = ap.packu;
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end
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else
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begin
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assign ap_packu = 1'b0;
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end
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if ( (pt.BITMANIP_ZBB == 1) | (pt.BITMANIP_ZBP == 1) | (pt.BITMANIP_ZBE == 1) | (pt.BITMANIP_ZBF == 1) )
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begin
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assign ap_pack = ap.pack;
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assign ap_packh = ap.packh;
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end
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else
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begin
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assign ap_pack = 1'b0;
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assign ap_packh = 1'b0;
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end
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if (pt.BITMANIP_ZBA == 1)
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begin
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assign ap_sh1add = ap.sh1add;
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assign ap_sh2add = ap.sh2add;
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assign ap_sh3add = ap.sh3add;
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assign ap_zba = ap.zba;
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end
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else
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begin
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assign ap_sh1add = 1'b0;
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assign ap_sh2add = 1'b0;
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assign ap_sh3add = 1'b0;
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assign ap_zba = 1'b0;
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end
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// *** End - BitManip ***
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rvdffpcie #(31) i_pc_ff (.*, .clk(clk), .en(enable), .din(pc_in[31:1]), .dout(pc_ff[31:1])); // any PC is run through here - doesn't have to be alu
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rvdffe #(32) i_result_ff (.*, .clk(clk), .en(enable & valid_in), .din(result[31:0]), .dout(result_ff[31:0]));
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// immediates are just muxed into rs2
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// add => add=1;
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// sub => add=1; sub=1;
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// and => lctl=3
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// or => lctl=2
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// xor => lctl=1
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// sll => sctl=3
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// srl => sctl=2
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// sra => sctl=1
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// slt => slt
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// lui => lctl=2; or x0, imm20 previously << 12
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// auipc => add; add pc, imm20 previously << 12
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// beq => bctl=4; add; add x0, pc, sext(offset[12:1])
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// bne => bctl=3; add; add x0, pc, sext(offset[12:1])
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// blt => bctl=2; add; add x0, pc, sext(offset[12:1])
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// bge => bctl=1; add; add x0, pc, sext(offset[12:1])
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// jal => rs1=pc {pc[31:1],1'b0}, rs2=sext(offset20:1]); rd=pc+[2,4]
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// jalr => rs1=rs1, rs2=sext(offset20:1]); rd=pc+[2,4]
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assign zba_a_in[31:0] = ( {32{ ap_sh1add}} & {a_in[30:0],1'b0} ) |
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( {32{ ap_sh2add}} & {a_in[29:0],2'b0} ) |
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( {32{ ap_sh3add}} & {a_in[28:0],3'b0} ) |
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( {32{~ap_zba }} & a_in[31:0] );
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logic [31:0] bm;
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assign bm[31:0] = ( ap.sub ) ? ~b_in[31:0] : b_in[31:0];
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assign {cout, aout[31:0]} = {1'b0, zba_a_in[31:0]} + {1'b0, bm[31:0]} + {32'b0, ap.sub};
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assign ov = (~a_in[31] & ~bm[31] & aout[31]) |
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( a_in[31] & bm[31] & ~aout[31] );
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assign lt = (~ap.unsign & (neg ^ ov)) |
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( ap.unsign & ~cout);
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assign eq = (a_in[31:0] == b_in[31:0]);
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assign ne = ~eq;
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assign neg = aout[31];
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assign ge = ~lt;
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assign lout[31:0] = ( {32{csr_ren_in }} & csr_rddata_in[31:0] ) |
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( {32{ap.land & ~ap_zbb}} & a_in[31:0] & b_in[31:0] ) |
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( {32{ap.lor & ~ap_zbb}} & (a_in[31:0] | b_in[31:0]) ) |
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( {32{ap.lxor & ~ap_zbb}} & (a_in[31:0] ^ b_in[31:0]) ) |
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( {32{ap.land & ap_zbb}} & a_in[31:0] & ~b_in[31:0] ) |
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( {32{ap.lor & ap_zbb}} & (a_in[31:0] | ~b_in[31:0]) ) |
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( {32{ap.lxor & ap_zbb}} & (a_in[31:0] ^ ~b_in[31:0]) );
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// * * * * * * * * * * * * * * * * * * BitManip : ROL,ROR * * * * * * * * * * * * * * * * * *
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// * * * * * * * * * * * * * * * * * * BitManip : ZBEXT * * * * * * * * * * * * * * * * * *
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logic [5:0] shift_amount;
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logic [31:0] shift_mask;
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logic [62:0] shift_extend;
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logic [62:0] shift_long;
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assign shift_amount[5:0] = ( { 6{ap.sll}} & (6'd32 - {1'b0,b_in[4:0]}) ) | // [5] unused
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( { 6{ap.srl}} & {1'b0,b_in[4:0]} ) |
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( { 6{ap.sra}} & {1'b0,b_in[4:0]} ) |
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( { 6{ap_rol}} & (6'd32 - {1'b0,b_in[4:0]}) ) |
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( { 6{ap_ror}} & {1'b0,b_in[4:0]} ) |
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( { 6{ap_bext}} & {1'b0,b_in[4:0]} );
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assign shift_mask[31:0] = ( 32'hffffffff << ({5{ap.sll}} & b_in[4:0]) );
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assign shift_extend[31:0] = a_in[31:0];
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assign shift_extend[62:32] = ( {31{ap.sra}} & {31{a_in[31]}} ) |
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( {31{ap.sll}} & a_in[30:0] ) |
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( {31{ap_rol}} & a_in[30:0] ) |
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( {31{ap_ror}} & a_in[30:0] );
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assign shift_long[62:0] = ( shift_extend[62:0] >> shift_amount[4:0] ); // 62-32 unused
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assign sout[31:0] = shift_long[31:0] & shift_mask[31:0];
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// * * * * * * * * * * * * * * * * * * BitManip : CLZ,CTZ * * * * * * * * * * * * * * * * * *
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logic bitmanip_clz_ctz_sel;
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logic [31:0] bitmanip_a_reverse_ff;
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logic [31:0] bitmanip_lzd_in;
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logic [5:0] bitmanip_dw_lzd_enc;
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logic [5:0] bitmanip_clz_ctz_result;
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assign bitmanip_clz_ctz_sel = ap_clz | ap_ctz;
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assign bitmanip_a_reverse_ff[31:0] = {a_in[0], a_in[1], a_in[2], a_in[3], a_in[4], a_in[5], a_in[6], a_in[7],
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a_in[8], a_in[9], a_in[10], a_in[11], a_in[12], a_in[13], a_in[14], a_in[15],
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a_in[16], a_in[17], a_in[18], a_in[19], a_in[20], a_in[21], a_in[22], a_in[23],
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a_in[24], a_in[25], a_in[26], a_in[27], a_in[28], a_in[29], a_in[30], a_in[31]};
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assign bitmanip_lzd_in[31:0] = ( {32{ap_clz}} & a_in[31:0] ) |
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( {32{ap_ctz}} & bitmanip_a_reverse_ff[31:0]);
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logic [31:0] bitmanip_lzd_os;
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integer i;
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logic found;
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always_comb
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begin
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bitmanip_lzd_os[31:0] = bitmanip_lzd_in[31:0];
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bitmanip_dw_lzd_enc[5:0]= 6'b0;
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found = 1'b0;
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for (int i=0; i<32 && found==0; i++) begin
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if (bitmanip_lzd_os[31] == 1'b0) begin
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bitmanip_dw_lzd_enc[5:0]= bitmanip_dw_lzd_enc[5:0] + 6'b00_0001;
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bitmanip_lzd_os[31:0] = bitmanip_lzd_os[31:0] << 1;
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end
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else
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found=1'b1;
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end
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end
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assign bitmanip_clz_ctz_result[5:0] = {6{bitmanip_clz_ctz_sel}} & {bitmanip_dw_lzd_enc[5],( {5{~bitmanip_dw_lzd_enc[5]}} & bitmanip_dw_lzd_enc[4:0] )};
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// * * * * * * * * * * * * * * * * * * BitManip : CPOP * * * * * * * * * * * * * * * * * *
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logic [5:0] bitmanip_cpop;
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logic [5:0] bitmanip_cpop_result;
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integer bitmanip_cpop_i;
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always_comb
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begin
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bitmanip_cpop[5:0] = 6'b0;
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for (bitmanip_cpop_i=0; bitmanip_cpop_i<32; bitmanip_cpop_i++)
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begin
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bitmanip_cpop[5:0] = bitmanip_cpop[5:0] + {5'b0,a_in[bitmanip_cpop_i]};
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end // FOR bitmanip_cpop_i
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end // ALWAYS_COMB
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assign bitmanip_cpop_result[5:0] = {6{ap_cpop}} & bitmanip_cpop[5:0];
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// * * * * * * * * * * * * * * * * * * BitManip : SEXT_B,SEXT_H * * * * * * * * * * * * * * * * *
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logic [31:0] bitmanip_sext_result;
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assign bitmanip_sext_result[31:0] = ( {32{ap_sext_b}} & { {24{a_in[7]}} ,a_in[7:0] } ) |
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( {32{ap_sext_h}} & { {16{a_in[15]}},a_in[15:0] } );
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// * * * * * * * * * * * * * * * * * * BitManip : MIN,MAX,MINU,MAXU * * * * * * * * * * * * * * *
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logic bitmanip_minmax_sel;
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logic [31:0] bitmanip_minmax_result;
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assign bitmanip_minmax_sel = ap_min | ap_max;
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logic bitmanip_minmax_sel_a;
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assign bitmanip_minmax_sel_a = ge ^ ap_min;
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assign bitmanip_minmax_result[31:0] = ({32{bitmanip_minmax_sel & bitmanip_minmax_sel_a}} & a_in[31:0]) |
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({32{bitmanip_minmax_sel & ~bitmanip_minmax_sel_a}} & b_in[31:0]);
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// * * * * * * * * * * * * * * * * * * BitManip : PACK, PACKU, PACKH * * * * * * * * * * * * * * *
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logic [31:0] bitmanip_pack_result;
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logic [31:0] bitmanip_packu_result;
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logic [31:0] bitmanip_packh_result;
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assign bitmanip_pack_result[31:0] = {32{ap_pack}} & {b_in[15:0], a_in[15:0]};
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assign bitmanip_packu_result[31:0] = {32{ap_packu}} & {b_in[31:16],a_in[31:16]};
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assign bitmanip_packh_result[31:0] = {32{ap_packh}} & {16'b0,b_in[7:0],a_in[7:0]};
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// * * * * * * * * * * * * * * * * * * BitManip : REV, ORC_B * * * * * * * * * * * * * * * * * *
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logic [31:0] bitmanip_rev8_result;
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logic [31:0] bitmanip_orc_b_result;
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assign bitmanip_rev8_result[31:0] = {32{ap_rev8}} & {a_in[7:0],a_in[15:8],a_in[23:16],a_in[31:24]};
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// uint32_t gorc32(uint32_t rs1, uint32_t rs2)
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// {
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// uint32_t x = rs1;
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// int shamt = rs2 & 31; ORC.B ORC16
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// if (shamt & 1) x |= ((x & 0x55555555) << 1) | ((x & 0xAAAAAAAA) >> 1); 1 0
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// if (shamt & 2) x |= ((x & 0x33333333) << 2) | ((x & 0xCCCCCCCC) >> 2); 1 0
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// if (shamt & 4) x |= ((x & 0x0F0F0F0F) << 4) | ((x & 0xF0F0F0F0) >> 4); 1 0
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// if (shamt & 8) x |= ((x & 0x00FF00FF) << 8) | ((x & 0xFF00FF00) >> 8); 0 0
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// if (shamt & 16) x |= ((x & 0x0000FFFF) << 16) | ((x & 0xFFFF0000) >> 16); 0 1
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// return x;
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// }
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// BEFORE 31 , 30 , 29 , 28 , 27 , 26, 25, 24
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// shamt[0] b = a31|a30,a31|a30,a29|a28,a29|a28, a27|a26,a27|a26,a25|a24,a25|a24
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// shamt[1] c = b31|b29,b30|b28,b31|b29,b30|b28, b27|b25,b26|b24,b27|b25,b26|b24
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// shamt[2] d = c31|c27,c30|c26,c29|c25,c28|c24, c31|c27,c30|c26,c29|c25,c28|c24
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//
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// Expand d31 = c31 | c27;
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// = b31 | b29 | b27 | b25;
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// = a31|a30 | a29|a28 | a27|a26 | a25|a24
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assign bitmanip_orc_b_result[31:0] = {32{ap_orc_b}} & { {8{| a_in[31:24]}}, {8{| a_in[23:16]}}, {8{| a_in[15:8]}}, {8{| a_in[7:0]}} };
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// * * * * * * * * * * * * * * * * * * BitManip : ZBSET, ZBCLR, ZBINV * * * * * * * * * * * * * *
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logic [31:0] bitmanip_sb_1hot;
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logic [31:0] bitmanip_sb_data;
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assign bitmanip_sb_1hot[31:0] = ( 32'h00000001 << b_in[4:0] );
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assign bitmanip_sb_data[31:0] = ( {32{ap_bset}} & ( a_in[31:0] | bitmanip_sb_1hot[31:0]) ) |
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( {32{ap_bclr}} & ( a_in[31:0] & ~bitmanip_sb_1hot[31:0]) ) |
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( {32{ap_binv}} & ( a_in[31:0] ^ bitmanip_sb_1hot[31:0]) );
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assign sel_shift = ap.sll | ap.srl | ap.sra | ap_rol | ap_ror;
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assign sel_adder = (ap.add | ap.sub | ap_zba) & ~ap.slt & ~ap_min & ~ap_max;
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assign sel_pc = ap.jal | pp_in.pcall | pp_in.pja | pp_in.pret;
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assign csr_write_data[31:0]= (ap.csr_imm) ? b_in[31:0] : a_in[31:0];
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assign slt_one = ap.slt & lt;
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assign result[31:0] = lout[31:0] |
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({32{sel_shift}} & sout[31:0] ) |
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({32{sel_adder}} & aout[31:0] ) |
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({32{sel_pc}} & {pcout[31:1],1'b0} ) |
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({32{ap.csr_write}} & csr_write_data[31:0] ) |
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{31'b0, slt_one} |
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({32{ap_bext}} & {31'b0, sout[0]} ) |
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{26'b0, bitmanip_clz_ctz_result[5:0]} |
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{26'b0, bitmanip_cpop_result[5:0]} |
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bitmanip_sext_result[31:0] |
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bitmanip_minmax_result[31:0] |
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bitmanip_pack_result[31:0] |
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bitmanip_packu_result[31:0] |
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bitmanip_packh_result[31:0] |
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bitmanip_rev8_result[31:0] |
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bitmanip_orc_b_result[31:0] |
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bitmanip_sb_data[31:0];
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// *** branch handling ***
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assign any_jal = ap.jal |
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pp_in.pcall |
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pp_in.pja |
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pp_in.pret;
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assign actual_taken = (ap.beq & eq) |
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(ap.bne & ne) |
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(ap.blt & lt) |
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(ap.bge & ge) |
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any_jal;
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// for a conditional br pcout[] will be the opposite of the branch prediction
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// for jal or pcall, it will be the link address pc+2 or pc+4
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rvbradder ibradder (
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.pc ( pc_in[31:1] ),
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.offset ( brimm_in[12:1] ),
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.dout ( pcout[31:1] ));
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// pred_correct is for the npc logic
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// pred_correct indicates not to use the flush_path
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// for any_jal pred_correct==0
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assign pred_correct_out = (valid_in & ap.predict_nt & ~actual_taken & ~any_jal) |
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(valid_in & ap.predict_t & actual_taken & ~any_jal);
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// for any_jal adder output is the flush path
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assign flush_path_out[31:1]= (any_jal) ? aout[31:1] : pcout[31:1];
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// pcall and pret are included here
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assign cond_mispredict = (ap.predict_t & ~actual_taken) |
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(ap.predict_nt & actual_taken);
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// target mispredicts on ret's
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assign target_mispredict = pp_in.pret & (pp_in.prett[31:1] != aout[31:1]);
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assign flush_upper_out = (ap.jal | cond_mispredict | target_mispredict) & valid_in & ~flush_upper_x & ~flush_lower_r;
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assign flush_final_out = ( (ap.jal | cond_mispredict | target_mispredict) & valid_in & ~flush_upper_x ) | flush_lower_r;
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// .i 3
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// .o 2
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// .ilb hist[1] hist[0] taken
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// .ob newhist[1] newhist[0]
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// .type fd
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//
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// 00 0 01
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// 01 0 01
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// 10 0 00
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// 11 0 10
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// 00 1 10
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// 01 1 00
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// 10 1 11
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// 11 1 11
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assign newhist[1] = ( pp_in.hist[1] & pp_in.hist[0]) | (~pp_in.hist[0] & actual_taken);
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assign newhist[0] = (~pp_in.hist[1] & ~actual_taken) | ( pp_in.hist[1] & actual_taken);
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always_comb begin
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predict_p_out = pp_in;
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predict_p_out.misp = ~flush_upper_x & ~flush_lower_r & (cond_mispredict | target_mispredict);
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predict_p_out.ataken = actual_taken;
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predict_p_out.hist[1] = newhist[1];
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predict_p_out.hist[0] = newhist[0];
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end
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endmodule // el2_exu_alu_ctl
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