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[/] [altor32/] [trunk/] [rtl/] [cpu/] [altor32_funcs.v] - Blame information for rev 37

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Line No. Rev Author Line
1 27 ultra_embe
//-----------------------------------------------------------------
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//                           AltOR32 
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//                Alternative Lightweight OpenRisc 
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//                            V2.1
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//                     Ultra-Embedded.com
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//                   Copyright 2011 - 2014
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//
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//               Email: admin@ultra-embedded.com
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//
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//                       License: LGPL
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//-----------------------------------------------------------------
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//
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// Copyright (C) 2011 - 2014 Ultra-Embedded.com
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//
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// This source file may be used and distributed without         
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// restriction provided that this copyright statement is not    
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// removed from the file and that any derivative work contains  
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// the original copyright notice and the associated disclaimer. 
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//
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// This source file is free software; you can redistribute it   
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// and/or modify it under the terms of the GNU Lesser General   
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// Public License as published by the Free Software Foundation; 
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// either version 2.1 of the License, or (at your option) any   
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// later version.
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//
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// This source is distributed in the hope that it will be       
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// useful, but WITHOUT ANY WARRANTY; without even the implied   
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// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      
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// PURPOSE.  See the GNU Lesser General Public License for more 
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// details.
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//
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// You should have received a copy of the GNU Lesser General    
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// Public License along with this source; if not, write to the 
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// Free Software Foundation, Inc., 59 Temple Place, Suite 330, 
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// Boston, MA  02111-1307  USA
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//-----------------------------------------------------------------
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//-----------------------------------------------------------------
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// less_than_signed: Less than operator (signed)
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// Inputs: x = left operand, y = right operand
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// Return: (int)x < (int)y
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//-----------------------------------------------------------------
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function [0:0] less_than_signed;
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    input  [31:0] x;
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    input  [31:0] y;
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    reg [31:0] v;
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begin
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    v = (x - y);
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    if (x[31] != y[31])
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        less_than_signed = x[31];
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    else
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        less_than_signed = v[31];
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end
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endfunction
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//-----------------------------------------------------------------
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// less_than_equal_signed: Less than or equal to operator (signed)
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// Inputs: x = left operand, y = right operand
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// Return: (int)x <= (int)y
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//-----------------------------------------------------------------
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function [0:0] less_than_equal_signed;
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    input  [31:0] x;
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    input  [31:0] y;
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    reg [31:0] v;
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begin
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    v = (x - y);
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    if (x == y)
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        less_than_equal_signed = 1'b1;
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    else if (x[31] != y[31])
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        less_than_equal_signed = x[31];
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    else
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        less_than_equal_signed = v[31];
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end
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endfunction
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//-----------------------------------------------------------------
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// greater_than_signed: Greater than operator (signed)
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// Inputs: x = left operand, y = right operand
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// Return: (int)x > (int)y
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//-----------------------------------------------------------------
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function [0:0] greater_than_signed;
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    input  [31:0] x;
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    input  [31:0] y;
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    reg [31:0] v;
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begin
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    v = (y - x);
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    if (x[31] != y[31])
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        greater_than_signed = y[31];
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    else
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        greater_than_signed = v[31];
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end
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endfunction
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//-----------------------------------------------------------------
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// greater_than_equal_signed: Greater than or equal to operator (signed)
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// Inputs: x = left operand, y = right operand
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// Return: (int)x >= (int)y
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//-----------------------------------------------------------------
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function [0:0] greater_than_equal_signed;
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    input  [31:0] x;
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    input  [31:0] y;
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    reg [31:0] v;
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begin
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    v = (y - x);
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    if (x == y)
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        greater_than_equal_signed = 1'b1;
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    else if (x[31] != y[31])
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        greater_than_equal_signed = y[31];
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    else
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        greater_than_equal_signed = v[31];
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end
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endfunction
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//-----------------------------------------------------------------
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// sign_extend_imm16: Extend 16-bit signed value to 32-bit signed.
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// Inputs: x = operand
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// Return: (int)((short)x)
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//-----------------------------------------------------------------
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function [31:0] sign_extend_imm16;
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    input  [15:0] x;
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    reg [31:0] y;
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begin
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    if (x[15] == 1'b0)
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        y[31:16] = 16'b0000000000000000;
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    else
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        y[31:16] = 16'b1111111111111111;
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    y[15:0] = x;
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    sign_extend_imm16 = y;
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end
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endfunction
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//-----------------------------------------------------------------
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// sign_extend_imm26: Extend 26-bit signed value to 32-bit signed.
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// Inputs: x = operand
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// Return: (int)((short)x)
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//-----------------------------------------------------------------
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function [31:0] sign_extend_imm26;
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    input  [25:0] x;
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    reg [31:0] y;
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begin
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    if (x[25] == 1'b0)
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        y[31:26] = 6'b000000;
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    else
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        y[31:26] = 6'b111111;
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    y[25:0] = x;
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    sign_extend_imm26 = y;
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end
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endfunction
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//-----------------------------------------------------------------
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// extend_imm16: Extend 16-bit unsigned value to 32-bit unsigned.
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// Inputs: x = operand
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// Return: (unsigned int)x
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//-----------------------------------------------------------------
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function [31:0] extend_imm16;
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    input  [15:0] x;
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begin
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    extend_imm16 = {16'h0000,x};
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end
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endfunction
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//-----------------------------------------------------------------
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// less_than_zero: Is signed value less than 0?
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// Inputs: x = operand
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// Return: ((int)x) < 0
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//-----------------------------------------------------------------
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function [0:0] less_than_zero;
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    input  [31:0] x;
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begin
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    if ((x != 32'h00000000) & (x[31] == 1'b1))
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        less_than_zero = 1'b1;
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    else
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        less_than_zero = 1'b0;
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end
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endfunction
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//-----------------------------------------------------------------
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// less_than_equal_zero: Is signed value less than or equal to 0?
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// Inputs: x = operand
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// Return: ((int)x) <= 0
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//-----------------------------------------------------------------
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function [0:0] less_than_equal_zero;
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    input  [31:0] x;
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begin
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    if ((x == 32'h00000000) | (x[31] == 1'b1))
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        less_than_equal_zero = 1'b1;
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    else
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        less_than_equal_zero = 1'b0;
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end
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endfunction
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//-----------------------------------------------------------------
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// more_than_equal_zero: Is signed value more than or equal to 0?
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// Inputs: x = operand
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// Return: ((int)x) >= 0
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//-----------------------------------------------------------------
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function [0:0] more_than_equal_zero;
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    input  [31:0] x;
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begin
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    if ((x == 32'h00000000) | (x[31] == 1'b0))
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        more_than_equal_zero = 1'b1;
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    else
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        more_than_equal_zero = 1'b0;
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end
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endfunction
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//-----------------------------------------------------------------
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// more_than_equal_zero: Is signed value more than 0?
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// Inputs: x = operand
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// Return: ((int)x) > 0
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//-----------------------------------------------------------------
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function [0:0] more_than_zero;
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    input  [31:0] x;
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begin
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    if (((x != 32'h00000000) & (x[31] == 1'b0)))
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        more_than_zero = 1'b1;
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    else
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        more_than_zero = 1'b0;
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end
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endfunction
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//-----------------------------------------------------------------
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// is_load_operation: Is this opcode a load operation?
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// Inputs: opcode
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// Return: 1 or 0
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//-----------------------------------------------------------------
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function [0:0] is_load_operation;
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    input [7:0] opcode;
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begin
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    is_load_operation = (opcode == `INST_OR32_LBS ||
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                         opcode == `INST_OR32_LBZ ||
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                         opcode == `INST_OR32_LHS ||
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                         opcode == `INST_OR32_LHZ ||
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                         opcode == `INST_OR32_LWZ ||
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                         opcode == `INST_OR32_LWS) ? 1'b1 : 1'b0;
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end
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endfunction
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//-----------------------------------------------------------------
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// is_store_operation: Is this opcode a store operation?
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// Inputs: opcode
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// Return: 1 or 0
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//-----------------------------------------------------------------
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function [0:0] is_store_operation;
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    input [7:0] opcode;
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begin
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    is_store_operation = (opcode == `INST_OR32_SB ||
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                          opcode == `INST_OR32_SH ||
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                          opcode == `INST_OR32_SW) ? 1'b1 : 1'b0;
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end
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endfunction

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