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robfinch |
// ============================================================================
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// __
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// \\__/ o\ (C) 2017-2018 Robert Finch, Waterloo
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// \ __ / All rights reserved.
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// \/_// robfinch<remove>@finitron.ca
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// ||
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//
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// FT64_FCU_Calc.v
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// - FT64 flow control calcs
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//
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// This source file is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published
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// by the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This source file is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU 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 License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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//
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// ============================================================================
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//
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`include ".\FT64_defines.vh"
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module FT64_FCU_Calc(ol, instr, tvec, a, i, pc, im, waitctr, bus);
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parameter WID = 64;
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parameter AMSB = 31;
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input [1:0] ol;
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input [47:0] instr;
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input [WID-1:0] tvec;
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input [WID-1:0] a;
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input [WID-1:0] i;
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input [AMSB:0] pc;
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input [2:0] im;
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input [WID-1:0] waitctr;
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output reg [WID-1:0] bus;
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always @*
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begin
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casez(instr[`INSTRUCTION_OP])
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`BRK: bus <= {{56{1'b0}},instr[15:8]};
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`BBc:
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case(instr[20:19])
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`IBNE: bus <= a + 64'd1;
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`DBNZ: bus <= a - 64'd1;
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default: bus <= 64'hCCCCCCCCCCCCCCCC;
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endcase
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`JAL: bus <= pc + (instr[6] ? 32'd6 : 32'd4);
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`CALL: bus <= pc + (instr[6] ? 32'd6 : 32'd4);
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`RET: bus <= a + i;
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`REX:
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case(ol)
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`OL_USER: bus <= 64'hCCCCCCCCCCCCCCCC;
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// ToDo: fix im test
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default: bus <= (im < ~ol) ? tvec : pc + 32'd4;
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endcase
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`WAIT: bus = waitctr==64'd1;
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default: bus <= 64'hCCCCCCCCCCCCCCCC;
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endcase
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end
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endmodule
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