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dmitryr |
// ========== Copyright Header Begin ==========================================
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//
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// OpenSPARC T1 Processor File: sparc_exu_eclbyplog_rs1.v
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// Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
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// DO NOT ALTER OR REMOVE COPYRIGHT NOTICES.
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//
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// The above named program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public
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// License version 2 as published by the Free Software Foundation.
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//
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// The above named program is distributed in the hope that it will be
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// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public
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// License along with this work; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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//
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// ========== Copyright Header End ============================================
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////////////////////////////////////////////////////////////////////////
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/*
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// Module Name: sparc_exu_eclbyplog_rs1
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// Description: This block implements the bypass logic for a single
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// operand. It takes the destination registers of all
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// four forwarding sources and the rs. It also has the
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// thread for the instruction in each stage and whether
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// the instruction writes to the register file. It won't
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// bypass if bypass_enable is low or rs =0. This is for the
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// special case of rs1 which has two bypass sets. One uses
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// the pc as an input (other) and one does not.
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*/
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module sparc_exu_eclbyplog_rs1 (/*AUTOARG*/
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// Outputs
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rs_sel_mux1_m, rs_sel_mux1_w, rs_sel_mux1_w2, rs_sel_mux1_other,
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rs_sel_mux2_usemux1, rs_sel_mux2_rf, rs_sel_mux2_e,
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rs_sel_mux2_ld, rs_sel_longmux_g2, rs_sel_longmux_w2,
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rs_sel_longmux_ldxa, ecl_byp_rcc_mux1_sel_m,
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ecl_byp_rcc_mux1_sel_w, ecl_byp_rcc_mux1_sel_w2,
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ecl_byp_rcc_mux1_sel_other, ecl_byp_rcc_mux2_sel_usemux1,
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ecl_byp_rcc_mux2_sel_rf, ecl_byp_rcc_mux2_sel_e,
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ecl_byp_rcc_mux2_sel_ld,
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// Inputs
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sehold, use_other, rs, rd_e, rd_m, ecl_irf_rd_w, ld_rd_g,
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wb_byplog_rd_w2, wb_byplog_rd_g2, tid_d, thr_match_de,
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thr_match_dm, ecl_irf_tid_w, ld_thr_match_dg, wb_byplog_tid_w2,
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ld_thr_match_dg2, ifu_exu_kill_e, wb_e, bypass_m,
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lsu_exu_dfill_vld_g, bypass_w, wb_byplog_wen_w2, wb_byplog_wen_g2,
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ecl_byp_ldxa_g
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) ;
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input sehold;
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input use_other;
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input [4:0] rs; // source register
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input [4:0] rd_e; // destination regs for all stages
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input [4:0] rd_m;
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input [4:0] ecl_irf_rd_w;
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input [4:0] ld_rd_g;
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input [4:0] wb_byplog_rd_w2;
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input [4:0] wb_byplog_rd_g2;
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input [1:0] tid_d;
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input thr_match_de;
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input thr_match_dm;
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input [1:0] ecl_irf_tid_w;
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input ld_thr_match_dg;
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input [1:0] wb_byplog_tid_w2;
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input ld_thr_match_dg2;
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input ifu_exu_kill_e;
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input wb_e; // whether each stage writes to reg
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input bypass_m; // file
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input lsu_exu_dfill_vld_g;
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input bypass_w;
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input wb_byplog_wen_w2;
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input wb_byplog_wen_g2;
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input ecl_byp_ldxa_g;
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output rs_sel_mux1_m;
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output rs_sel_mux1_w;
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output rs_sel_mux1_w2;
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output rs_sel_mux1_other;
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output rs_sel_mux2_usemux1;
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output rs_sel_mux2_rf;
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output rs_sel_mux2_e;
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output rs_sel_mux2_ld;
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output rs_sel_longmux_g2;
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output rs_sel_longmux_w2;
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output rs_sel_longmux_ldxa;
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output ecl_byp_rcc_mux1_sel_m;
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output ecl_byp_rcc_mux1_sel_w;
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output ecl_byp_rcc_mux1_sel_w2;
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output ecl_byp_rcc_mux1_sel_other;
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output ecl_byp_rcc_mux2_sel_usemux1;
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output ecl_byp_rcc_mux2_sel_rf;
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output ecl_byp_rcc_mux2_sel_e;
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output ecl_byp_rcc_mux2_sel_ld;
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wire use_e, use_m, use_w, use_w2, use_rf, use_ld, use_ldxa;
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wire match_e, match_m, match_w, match_w2, match_ld; // outputs of comparison
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wire match_g2;
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wire bypass; // boolean that allows bypassing
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wire rs_is_nonzero;
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wire rcc_bypass;
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// Don't bypass if rs == 0 or we are supposed to use other
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assign rs_is_nonzero = rs[0]|rs[1]|rs[2]|rs[3]|rs[4];
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assign bypass = rs_is_nonzero & ~use_other & ~sehold;
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// Normal pipe priority: E, M, W, RF
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// Ld priority: LD, RF
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// W2 priority: W2, RF
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assign use_e = match_e & wb_e & ~ifu_exu_kill_e;
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assign use_m = match_m & bypass_m & ~use_e;
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assign use_w = match_w & bypass_w & ~use_m & ~use_e;
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assign use_ld = match_ld & lsu_exu_dfill_vld_g & ~ecl_byp_ldxa_g;
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assign use_ldxa = match_ld & ecl_byp_ldxa_g;
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assign use_w2 = (match_w2 & wb_byplog_wen_w2 | match_g2 & wb_byplog_wen_g2) & ~use_e & ~use_m;
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assign use_rf = ~use_w2 & ~use_w & ~use_m & ~use_e & ~use_ld & ~use_ldxa;
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// mux1[M, W, W2, OTHER(optional)]
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// mux2[mux1, RF, E, LD]
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assign rs_sel_mux2_e = (use_e & bypass);
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assign rs_sel_mux2_rf = ((use_rf | ~bypass) & ~use_other);
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assign rs_sel_mux2_ld = (use_ld & ~use_e & ~use_w & ~use_m & ~use_w2 & bypass);
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assign rs_sel_mux2_usemux1 = (use_other & ~sehold) | (~rs_sel_mux1_other & ~use_e);
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assign rs_sel_mux1_other = ~((use_m | use_w | use_w2 | use_ldxa) & bypass);
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assign rs_sel_mux1_w2 = ((use_ldxa | use_w2) & bypass);
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assign rs_sel_mux1_w = (use_w & ~use_w2 & ~use_ldxa & bypass);
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assign rs_sel_mux1_m = (use_m & ~use_w2 & ~use_ldxa & bypass);
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assign rs_sel_longmux_ldxa = use_ldxa;
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assign rs_sel_longmux_g2 = match_g2 & wb_byplog_wen_g2 & ~use_ldxa;
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assign rs_sel_longmux_w2 = ~use_ldxa & ~(match_g2 & wb_byplog_wen_g2);
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// Bypassing for cc generation (don't use other input)
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assign rcc_bypass = rs_is_nonzero;
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assign ecl_byp_rcc_mux2_sel_e = use_e & rcc_bypass;
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assign ecl_byp_rcc_mux2_sel_rf = use_rf | ~rcc_bypass;
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assign ecl_byp_rcc_mux2_sel_ld = use_ld & ~use_e & ~use_w & ~use_m & ~use_w2 & rcc_bypass;
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assign ecl_byp_rcc_mux2_sel_usemux1 = (use_m | use_w | use_w2 | use_ldxa) & rcc_bypass & ~use_e;
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assign ecl_byp_rcc_mux1_sel_other = ~(use_m | use_w | use_w2 | use_ldxa);
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assign ecl_byp_rcc_mux1_sel_w2 = use_w2 | use_ldxa;
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assign ecl_byp_rcc_mux1_sel_w = use_w & ~use_w2 & ~use_ldxa;
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assign ecl_byp_rcc_mux1_sel_m = use_m & ~use_w2 & ~use_ldxa;
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// Comparisons
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assign match_e = thr_match_de & (rs[4:0] == rd_e[4:0]);
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// sparc_exu_eclcomp7 e_comp7(.out(match_e), .in1({tid_d[1:0],rs[4:0]}),
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// .in2({ecl_rml_tid_e[1:0],rd_e[4:0]}));
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assign match_m = thr_match_dm & (rs[4:0] == rd_m[4:0]);
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// sparc_exu_eclcomp7 m_comp7(.out(match_m), .in1({tid_d[1:0],rs[4:0]}),
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// .in2({tid_m[1:0],rd_m[4:0]}));
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sparc_exu_eclcomp7 w_comp7(.out(match_w), .in1({tid_d[1:0],rs[4:0]}),
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.in2({ecl_irf_tid_w[1:0],ecl_irf_rd_w[4:0]}));
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sparc_exu_eclcomp7 w2_comp7(.out(match_w2), .in1({tid_d[1:0],rs[4:0]}),
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.in2({wb_byplog_tid_w2[1:0],wb_byplog_rd_w2[4:0]}));
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assign match_ld = ld_thr_match_dg & (rs[4:0] == ld_rd_g[4:0]);
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assign match_g2 = ld_thr_match_dg2 & (rs[4:0] == wb_byplog_rd_g2[4:0]);
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/* -----\/----- EXCLUDED -----\/-----
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sparc_exu_eclcomp7 ld_comp7(.out(match_ld), .in1({tid_d[1:0],rs[4:0]}),
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.in2({ld_tid_g[1:0],ld_rd_g[4:0]}));
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sparc_exu_eclcomp7 g2_comp7(.out(match_g2), .in1({tid_d[1:0],rs[4:0]}),
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.in2({wb_byplog_tid_g2[1:0],wb_byplog_rd_g2[4:0]}));
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-----/\----- EXCLUDED -----/\----- */
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endmodule // sparc_exu_eclbyplog
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