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[/] [amber/] [trunk/] [hw/] [vlog/] [amber23/] [a23_functions.vh] - Rev 86
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////////////////////////////////////////////////////////////////// // // // Functions for Amber 2 Core // // // // This file is part of the Amber project // // http://www.opencores.org/project,amber // // // // Description // // Functions used in more than one module // // // // Author(s): // // - Conor Santifort, csantifort.amber@gmail.com // // // ////////////////////////////////////////////////////////////////// // // // Copyright (C) 2010 Authors and OPENCORES.ORG // // // // This source file may be used and distributed without // // restriction provided that this copyright statement is not // // removed from the file and that any derivative work contains // // the original copyright notice and the associated disclaimer. // // // // This source file is free software; you can redistribute it // // and/or modify it under the terms of the GNU Lesser General // // Public License as published by the Free Software Foundation; // // either version 2.1 of the License, or (at your option) any // // later version. // // // // This source is distributed in the hope that it will be // // useful, but WITHOUT ANY WARRANTY; without even the implied // // warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR // // PURPOSE. See the GNU Lesser General Public License for more // // details. // // // // You should have received a copy of the GNU Lesser General // // Public License along with this source; if not, download it // // from http://www.opencores.org/lgpl.shtml // // // ////////////////////////////////////////////////////////////////// // ======================================================== // PC Filter - Remove the status bits // ======================================================== function [31:0] pcf; input [31:0] pc_reg; begin pcf = {6'd0, pc_reg[25:2], 2'd0}; end endfunction // ======================================================== // 4-bit to 16-bit 1-hot decode // ======================================================== function [14:0] decode; input [3:0] reg_sel; begin case ( reg_sel ) 4'h0: decode = 15'h0001; 4'h1: decode = 15'h0002; 4'h2: decode = 15'h0004; 4'h3: decode = 15'h0008; 4'h4: decode = 15'h0010; 4'h5: decode = 15'h0020; 4'h6: decode = 15'h0040; 4'h7: decode = 15'h0080; 4'h8: decode = 15'h0100; 4'h9: decode = 15'h0200; 4'ha: decode = 15'h0400; 4'hb: decode = 15'h0800; 4'hc: decode = 15'h1000; 4'hd: decode = 15'h2000; 4'he: decode = 15'h4000; default: decode = 15'h0000; endcase end endfunction // ======================================================== // Convert Stats Bits Mode to one-hot encoded version // ======================================================== function [3:0] oh_status_bits_mode; input [1:0] fn_status_bits_mode; begin oh_status_bits_mode = fn_status_bits_mode == SVC ? 1'd1 << OH_SVC : fn_status_bits_mode == IRQ ? 1'd1 << OH_IRQ : fn_status_bits_mode == FIRQ ? 1'd1 << OH_FIRQ : 1'd1 << OH_USR ; end endfunction // ======================================================== // Convert mode into ascii name // ======================================================== function [(14*8)-1:0] mode_name; input [4:0] mode; begin mode_name = mode == USR ? "User " : mode == SVC ? "Supervisor " : mode == IRQ ? "Interrupt " : mode == FIRQ ? "Fast Interrupt" : "UNKNOWN " ; end endfunction // ======================================================== // Conditional Execution Function // ======================================================== // EQ Z set // NE Z clear // CS C set // CC C clear // MI N set // PL N clear // VS V set // VC V clear // HI C set and Z clear // LS C clear or Z set // GE N == V // LT N != V // GT Z == 0,N == V // LE Z == 1 or N != V // AL Always (unconditional) // NV Never function conditional_execute; input [3:0] condition; input [3:0] flags; begin conditional_execute = ( condition == AL ) || ( condition == EQ && flags[2] ) || ( condition == NE && !flags[2] ) || ( condition == CS && flags[1] ) || ( condition == CC && !flags[1] ) || ( condition == MI && flags[3] ) || ( condition == PL && !flags[3] ) || ( condition == VS && flags[0] ) || ( condition == VC && !flags[0] ) || ( condition == HI && flags[1] && !flags[2] ) || ( condition == LS && (!flags[1] || flags[2]) ) || ( condition == GE && flags[3] == flags[0] ) || ( condition == LT && flags[3] != flags[0] ) || ( condition == GT && !flags[2] && flags[3] == flags[0] ) || ( condition == LE && (flags[2] || flags[3] != flags[0])) ; end endfunction // ======================================================== // Log 2 // ======================================================== function [31:0] log2; input [31:0] num; integer i; integer out; begin out = 32'd0; for (i=0; i<30; i=i+1) if ((2**i > num) && (out == 0)) out = i-1; log2 = out; end endfunction
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