| ////////////////////////////////////////////////////////////////// |
| // // |
| // 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 |
