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//////////////////////////////////////////////////////////////////
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// //
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// Functions for Amber 2 Core //
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// //
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// This file is part of the Amber project //
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// http://www.opencores.org/project,amber //
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// //
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// Description //
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// Functions used in more than one module //
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// //
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// Author(s): //
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// - Conor Santifort, csantifort.amber@gmail.com //
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// //
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//////////////////////////////////////////////////////////////////
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// //
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// Copyright (C) 2010 Authors and OPENCORES.ORG //
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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, download it //
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// from http://www.opencores.org/lgpl.shtml //
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// //
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//////////////////////////////////////////////////////////////////
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// ========================================================
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// PC Filter - Remove the status bits
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// ========================================================
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function [31:0] pcf;
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input [31:0] pc_reg;
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begin
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pcf = {6'd0, pc_reg[25:2], 2'd0};
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end
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endfunction
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// ========================================================
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// 4-bit to 16-bit 1-hot decode
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// ========================================================
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function [14:0] decode;
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input [3:0] reg_sel;
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begin
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case ( reg_sel )
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4'h0: decode = 15'h0001;
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4'h1: decode = 15'h0002;
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4'h2: decode = 15'h0004;
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4'h3: decode = 15'h0008;
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4'h4: decode = 15'h0010;
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4'h5: decode = 15'h0020;
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4'h6: decode = 15'h0040;
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4'h7: decode = 15'h0080;
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4'h8: decode = 15'h0100;
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4'h9: decode = 15'h0200;
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4'ha: decode = 15'h0400;
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4'hb: decode = 15'h0800;
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4'hc: decode = 15'h1000;
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4'hd: decode = 15'h2000;
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4'he: decode = 15'h4000;
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default: decode = 15'h0000;
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endcase
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end
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endfunction
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// ========================================================
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// Convert Stats Bits Mode to one-hot encoded version
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// ========================================================
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function [3:0] oh_status_bits_mode;
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input [1:0] fn_status_bits_mode;
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begin
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oh_status_bits_mode =
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fn_status_bits_mode == SVC ? 1'd1 << OH_SVC :
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fn_status_bits_mode == IRQ ? 1'd1 << OH_IRQ :
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fn_status_bits_mode == FIRQ ? 1'd1 << OH_FIRQ :
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1'd1 << OH_USR ;
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end
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endfunction
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// ========================================================
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// Convert mode into ascii name
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// ========================================================
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function [(14*8)-1:0] mode_name;
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input [4:0] mode;
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begin
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mode_name = mode == USR ? "User " :
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mode == SVC ? "Supervisor " :
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mode == IRQ ? "Interrupt " :
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mode == FIRQ ? "Fast Interrupt" :
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"UNKNOWN " ;
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end
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endfunction
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// ========================================================
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// Conditional Execution Function
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// ========================================================
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// EQ Z set
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// NE Z clear
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// CS C set
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// CC C clear
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// MI N set
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// PL N clear
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// VS V set
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// VC V clear
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// HI C set and Z clear
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// LS C clear or Z set
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// GE N == V
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// LT N != V
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// GT Z == 0,N == V
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// LE Z == 1 or N != V
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// AL Always (unconditional)
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// NV Never
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function conditional_execute;
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input [3:0] condition;
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input [3:0] flags;
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begin
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conditional_execute
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= ( condition == AL ) ||
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( condition == EQ && flags[2] ) ||
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( condition == NE && !flags[2] ) ||
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( condition == CS && flags[1] ) ||
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( condition == CC && !flags[1] ) ||
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( condition == MI && flags[3] ) ||
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( condition == PL && !flags[3] ) ||
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( condition == VS && flags[0] ) ||
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( condition == VC && !flags[0] ) ||
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( condition == HI && flags[1] && !flags[2] ) ||
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( condition == LS && (!flags[1] || flags[2]) ) ||
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( condition == GE && flags[3] == flags[0] ) ||
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( condition == LT && flags[3] != flags[0] ) ||
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( condition == GT && !flags[2] && flags[3] == flags[0] ) ||
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( condition == LE && (flags[2] || flags[3] != flags[0])) ;
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end
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endfunction
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// ========================================================
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// Log 2
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// ========================================================
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function [31:0] log2;
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input [31:0] num;
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integer i;
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integer out;
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begin
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out = 32'd0;
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for (i=0; i<30; i=i+1)
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if ((2**i > num) && (out == 0))
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out = i-1;
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log2 = out;
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end
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endfunction
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