LFSR伪随机数发生器
----------------------------------------------------------------------------
---- Create Date: 14:30:08 07/28/2010 ----
---- Design Name: lfsr_pkg ----
---- Project Name: lfsr_randgen ----
---- Description: ----
---- This is the package file used in the lfsr_randgen project.The ----
---- package contain the function for XORing bits from various tap ----
---- locations depending on the generic parameter(width of lfsr ) ----
---- ----
----------------------------------------------------------------------------
---- ----
---- This file is a part of the lfsr_randgen project at ----
---- http://www.opencores.org/ ----
---- ----
---- Author(s): ----
---- Vipin Lal, [email protected] ----
---- ----
----------------------------------------------------------------------------
---- ----
---- 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 ----
---- ----
----------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
package lfsr_pkg is
function xor_gates( random : std_logic_vector) return std_logic;
end lfsr_pkg;
--Package body starts from here.
package body lfsr_pkg is
--function for XORing from tap values.
function xor_gates( random : std_logic_vector ) return std_logic is
variable xor_out : std_logic:='0';
variable rand : std_logic_vector(random'length-1 downto 0):=random;
begin
if(rand'length = 3) then --3
xor_out := rand(2) xor rand(1);
elsif(rand'length = 4) then --4
xor_out := rand(3) xor rand(2);
elsif(rand'length = 5) then --5
xor_out := rand(4) xor rand(2);
elsif(rand'length = 6) then --6
xor_out := rand(5) xor rand(4);
elsif(rand'length = 7) then --7
xor_out := rand(6) xor rand(5);
elsif(rand'length = 8) then --8
xor_out := rand(7) xor rand(5) xor rand(4) xor rand(3);
elsif(rand'length = 9) then --9
xor_out := rand(8) xor rand(4);
elsif(rand'length = 10)then --10
xor_out := rand(9) xor rand(6);
elsif(rand'length =11) then --11
xor_out := rand(10) xor rand(8);
elsif(rand'length = 12) then --12
xor_out := rand(11) xor rand(5) xor rand(3) xor rand(0);
elsif(rand'length = 13) then --13
xor_out := rand(12) xor rand(3) xor rand(2) xor rand(0);
elsif(rand'length = 14) then --14
xor_out := rand(13) xor rand(4) xor rand(2) xor rand(0);
elsif(rand'length = 15) then --15
xor_out := rand(14) xor rand(13);
elsif(rand'length = 16) then --16
xor_out := rand(15) xor rand(14) xor rand(12) xor rand(3);
elsif(rand'length = 17) then --17
xor_out := rand(16) xor rand(13);
elsif(rand'length = 18) then --18
xor_out := rand(17) xor rand(10);
elsif(rand'length = 19) then --19
xor_out := rand(18) xor rand(5) xor rand(1) xor rand(0);
elsif(rand'length = 20) then --20
xor_out := rand(19) xor rand(16);
elsif(rand'length = 21) then --21
xor_out := rand(20) xor rand(18);
elsif(rand'length = 22) then --22
xor_out := rand(21) xor rand(20);
elsif(rand'length = 23) then --23
xor_out := rand(22) xor rand(17);
elsif(rand'length = 24) then --24
xor_out := rand(23) xor rand(22) xor rand(21) xor rand(16);
elsif(rand'length = 25) then --25
xor_out := rand(24) xor rand(21);
elsif(rand'length = 26) then --26
xor_out := rand(25) xor rand(5) xor rand(1) xor rand(0);
elsif(rand'length = 27) then --27
xor_out := rand(26) xor rand(4) xor rand(1) xor rand(0);
elsif(rand'length = 28) then --28
xor_out := rand(27) xor rand(24);
elsif(rand'length = 29) then --29
xor_out := rand(28) xor rand(26);
elsif(rand'length = 30) then --30
xor_out := rand(29) xor rand(5) xor rand(3) xor rand(0);
elsif(rand'length = 31) then --31
xor_out := rand(30) xor rand(27);
elsif(rand'length = 32) then --32
xor_out := rand(31) xor rand(21) xor rand(1) xor rand(0);
elsif(rand'length = 33) then --33
xor_out := rand(32) xor rand(19);
elsif(rand'length = 34) then --34
xor_out := rand(33) xor rand(26) xor rand(1) xor rand(0);
elsif(rand'length = 35) then --35
xor_out := rand(34) xor rand(32);
elsif(rand'length = 36) then --36
xor_out := rand(35) xor rand(24);
elsif(rand'length = 37) then --37
xor_out := rand(36) xor rand(4) xor rand(3) xor rand(2) xor rand(1) xor rand(0);
elsif(rand'length = 38) then --38
xor_out := rand(37) xor rand(5) xor rand(4) xor rand(0);
elsif(rand'length = 39) then --39
xor_out := rand(38) xor rand(34);
elsif(rand'length = 40) then --40
xor_out := rand(39) xor rand(37) xor rand(20) xor rand(18);
elsif(rand'length = 41) then --41
xor_out := rand(40) xor rand(37);
elsif(rand'length = 42) then --42
xor_out := rand(41) xor rand(40) xor rand(19) xor rand(18);
elsif(rand'length = 43) then --43
xor_out := rand(42) xor rand(41) xor rand(37) xor rand(36);
elsif(rand'length = 44) then --44
xor_out := rand(43) xor rand(42) xor rand(17) xor rand(16);
elsif(rand'length = 45) then --45
xor_out := rand(44) xor rand(43) xor rand(41) xor rand(40);
elsif(rand'length = 46) then --46
xor_out := rand(45) xor rand(44) xor rand(25) xor rand(24);
elsif(rand'length = 47) then --47
xor_out := rand(46) xor rand(41);
elsif(rand'length = 48) then --48
xor_out := rand(47) xor rand(46) xor rand(20) xor rand(19);
elsif(rand'length = 49) then --49
xor_out := rand(48) xor rand(39);
elsif(rand'length = 50) then --50
xor_out := rand(49) xor rand(48) xor rand(23) xor rand(22);
elsif(rand'length = 51) then --51
xor_out := rand(50) xor rand(49) xor rand(35) xor rand(34);
elsif(rand'length = 52) then --52
xor_out := rand(51) xor rand(48);
elsif(rand'length = 53) then --53
xor_out := rand(52) xor rand(51) xor rand(37) xor rand(36);
elsif(rand'length = 54) then --54
xor_out := rand(53) xor rand(52) xor rand(17) xor rand(16);
elsif(rand'length = 55) then --55
xor_out := rand(54) xor rand(30);
elsif(rand'length = 56) then --56
xor_out := rand(55) xor rand(54) xor rand(34) xor rand(33);
elsif(rand'length = 57) then --57
xor_out := rand(56) xor rand(49);
elsif(rand'length = 58) then --58
xor_out := rand(57) xor rand(38);
elsif(rand'length = 59) then --59
xor_out := rand(58) xor rand(57) xor rand(37) xor rand(36);
elsif(rand'length = 60) then --60
xor_out := rand(59) xor rand(58);
elsif(rand'length = 61) then --61
xor_out := rand(60) xor rand(59) xor rand(45) xor rand(44);
elsif(rand'length = 62) then --62
xor_out := rand(61) xor rand(60) xor rand(5) xor rand(4);
elsif(rand'length = 63) then --63
xor_out := rand(62) xor rand(61);
elsif(rand'length = 64) then --64
xor_out := rand(63) xor rand(62) xor rand(60) xor rand(59);
elsif(rand'length = 65) then --65
xor_out := rand(64) xor rand(46);
elsif(rand'length = 66) then --66
xor_out := rand(65) xor rand(64) xor rand(56) xor rand(55);
elsif(rand'length = 67) then --67
xor_out := rand(66) xor rand(65) xor rand(57) xor rand(56);
elsif(rand'length = 68) then --68
xor_out := rand(67) xor rand(58);
elsif(rand'length = 69) then --69
xor_out := rand(68) xor rand(66) xor rand(41) xor rand(39);
elsif(rand'length = 70) then --70
xor_out := rand(69) xor rand(68) xor rand(54) xor rand(53);
elsif(rand'length = 71) then --71
xor_out := rand(70) xor rand(64);
elsif(rand'length = 72) then --72
xor_out := rand(71) xor rand(65) xor rand(24) xor rand(18);
elsif(rand'length = 73) then --73
xor_out := rand(72) xor rand(47);
elsif(rand'length = 74) then --74
xor_out := rand(73) xor rand(72) xor rand(58) xor rand(57);
elsif(rand'length = 75) then --75
xor_out := rand(74) xor rand(73) xor rand(64) xor rand(63);
elsif(rand'length = 76) then --76
xor_out := rand(75) xor rand(74) xor rand(40) xor rand(39);
elsif(rand'length = 77) then --77
xor_out := rand(76) xor rand(75) xor rand(46) xor rand(45);
elsif(rand'length = 78) then --78
xor_out := rand(77) xor rand(76) xor rand(58) xor rand(57);
elsif(rand'length = 79) then --79
xor_out := rand(78) xor rand(69);
elsif(rand'length = 80) then --80
xor_out := rand(79) xor rand(78) xor rand(42) xor rand(41);
elsif(rand'length = 81) then --81
xor_out := rand(80) xor rand(76);
elsif(rand'length = 82) then --82
xor_out := rand(81) xor rand(78) xor rand(46) xor rand(43);
elsif(rand'length = 83) then --83
xor_out := rand(82) xor rand(81) xor rand(37) xor rand(36);
elsif(rand'length = 84) then --84
xor_out := rand(83) xor rand(70);
elsif(rand'length = 85) then --85
xor_out := rand(84) xor rand(83) xor rand(57) xor rand(56);
elsif(rand'length = 86) then --86
xor_out := rand(85) xor rand(84) xor rand(73) xor rand(72);
elsif(rand'length = 87) then --87
xor_out := rand(86) xor rand(73);
elsif(rand'length = 88) then --88
xor_out := rand(87) xor rand(86) xor rand(16) xor rand(15);
elsif(rand'length = 89) then --89
xor_out := rand(88) xor rand(50);
elsif(rand'length = 90) then --90
xor_out := rand(89) xor rand(88) xor rand(71) xor rand(70);
elsif(rand'length = 91) then --91
xor_out := rand(90) xor rand(89) xor rand(7) xor rand(6);
elsif(rand'length = 92) then --92
xor_out := rand(91) xor rand(90) xor rand(79) xor rand(78);
elsif(rand'length = 93) then --93
xor_out := rand(92) xor rand(90);
elsif(rand'length = 94) then --94
xor_out := rand(93) xor rand(72);
elsif(rand'length = 95) then --95
xor_out := rand(94) xor rand(83);
elsif(rand'length = 96) then --96
xor_out := rand(95) xor rand(93) xor rand(48) xor rand(46);
elsif(rand'length = 97) then --97
xor_out := rand(96) xor rand(90);
elsif(rand'length = 98) then --98
xor_out := rand(97) xor rand(86);
elsif(rand'length = 99) then --99
xor_out := rand(98) xor rand(96) xor rand(53) xor rand(51);
elsif(rand'length = 100) then --100
xor_out := rand(99) xor rand(62);
elsif(rand'length = 101) then --101
xor_out := rand(100) xor rand(99) xor rand(94) xor rand(93);
elsif(rand'length = 102) then --102
xor_out := rand(101) xor rand(100) xor rand(35) xor rand(34);
elsif(rand'length = 103) then --103
xor_out := rand(102) xor rand(93);
elsif(rand'length = 104) then --104
xor_out := rand(103) xor rand(102) xor rand(93) xor rand(92);
elsif(rand'length = 105) then --105
xor_out := rand(104) xor rand(88);
elsif(rand'length = 106) then --106
xor_out := rand(105) xor rand(90);
elsif(rand'length = 107) then --107
xor_out := rand(106) xor rand(104) xor rand(43) xor rand(41);
elsif(rand'length = 108) then --108
xor_out := rand(107) xor rand(76);
elsif(rand'length = 109) then --109
xor_out := rand(108) xor rand(107) xor rand(102) xor rand(101);
elsif(rand'length = 110)then --110
xor_out := rand(109) xor rand(108) xor rand(97) xor rand(96);
elsif(rand'length = 111) then --111
xor_out := rand(110) xor rand(100);
elsif(rand'length = 112) then --112
xor_out := rand(111) xor rand(109) xor rand(68) xor rand(66);
elsif(rand'length = 113) then --113
xor_out := rand(112) xor rand(103);
elsif(rand'length = 114) then --114
xor_out := rand(113) xor rand(112) xor rand(32) xor rand(31);
elsif(rand'length = 115) then --115
xor_out := rand(114) xor rand(113) xor rand(100) xor rand(99);
elsif(rand'length = 116) then --116
xor_out := rand(115) xor rand(114) xor rand(45) xor rand(44);
elsif(rand'length = 117) then --117
xor_out := rand(116) xor rand(114) xor rand(98) xor rand(96);
elsif(rand'length = 118) then --118
xor_out := rand(117) xor rand(84);
elsif(rand'length = 119) then --119
xor_out := rand(118) xor rand(110);
elsif(rand'length = 120) then --120
xor_out := rand(119) xor rand(112) xor rand(8) xor rand(1);
elsif(rand'length = 121) then --121
xor_out := rand(120) xor rand(102);
elsif(rand'length = 122) then --122
xor_out := rand(121) xor rand(120) xor rand(62) xor rand(61);
elsif(rand'length = 123) then --123
xor_out := rand(122) xor rand(120);
elsif(rand'length = 124) then --124
xor_out := rand(123) xor rand(86);
elsif(rand'length = 125) then --125
xor_out := rand(124) xor rand(123) xor rand(17) xor rand(16);
elsif(rand'length = 126) then --126
xor_out := rand(125) xor rand(124) xor rand(89) xor rand(88);
elsif(rand'length = 127) then --127
xor_out := rand(126) xor rand(125);
elsif(rand'length = 128) then --128
xor_out := rand(127) xor rand(125) xor rand(100) xor rand(98);
elsif(rand'length = 129) then --129
xor_out := rand(128) xor rand(123);
elsif(rand'length = 130) then --130
xor_out := rand(129) xor rand(126);
elsif(rand'length = 131) then --131
xor_out := rand(130) xor rand(129) xor rand(83) xor rand(82);
elsif(rand'length = 132) then --132
xor_out := rand(131) xor rand(102);
elsif(rand'length = 133) then --133
xor_out := rand(132) xor rand(131) xor rand(81) xor rand(80);
elsif(rand'length = 134) then --134
xor_out := rand(133) xor rand(76);
elsif(rand'length = 135) then --135
xor_out := rand(134) xor rand(123);
elsif(rand'length = 136) then --136
xor_out := rand(135) xor rand(134) xor rand(10) xor rand(9);
elsif(rand'length = 137) then --137
xor_out := rand(136) xor rand(115);
elsif(rand'length = 138) then --138
xor_out := rand(137) xor rand(136) xor rand(130) xor rand(129);
elsif(rand'length = 139) then --139
xor_out := rand(138) xor rand(135) xor rand(133) xor rand(130);
elsif(rand'length = 140) then --140
xor_out := rand(139) xor rand(110);
elsif(rand'length = 141) then --141
xor_out := rand(140) xor rand(139) xor rand(109) xor rand(108);
elsif(rand'length = 142) then --142
xor_out := rand(141) xor rand(120);
elsif(rand'length = 143) then --143
xor_out := rand(142) xor rand(141) xor rand(122) xor rand(121);
elsif(rand'length = 144) then --144
xor_out := rand(143) xor rand(142) xor rand(74) xor rand(73);
elsif(rand'length = 145) then --145
xor_out := rand(144) xor rand(92);
elsif(rand'length = 146) then --146
xor_out := rand(145) xor rand(144) xor rand(86) xor rand(85);
elsif(rand'length = 147) then --147
xor_out := rand(146) xor rand(145) xor rand(109) xor rand(108);
elsif(rand'length = 148) then --148
xor_out := rand(147) xor rand(120);
elsif(rand'length = 149) then --149
xor_out := rand(148) xor rand(147) xor rand(39) xor rand(38);
elsif(rand'length = 150) then --150
xor_out := rand(149) xor rand(96);
elsif(rand'length = 151) then --151
xor_out := rand(150) xor rand(147);
elsif(rand'length = 152) then --152
xor_out := rand(151) xor rand(150) xor rand(86) xor rand(85);
elsif(rand'length = 153) then --153
xor_out := rand(152) xor rand(151);
elsif(rand'length = 154) then --154
xor_out := rand(153) xor rand(151) xor rand(26) xor rand(24);
elsif(rand'length = 155) then --155
xor_out := rand(154) xor rand(153) xor rand(123) xor rand(122);
elsif(rand'length = 156) then --156
xor_out := rand(155) xor rand(154) xor rand(40) xor rand(39);
elsif(rand'length = 157) then --157
xor_out := rand(156) xor rand(155) xor rand(130) xor rand(129);
elsif(rand'length = 158) then --158
xor_out := rand(157) xor rand(156) xor rand(131) xor rand(130);
elsif(rand'length = 159) then --159
xor_out := rand(158) xor rand(127);
elsif(rand'length = 160) then --160
xor_out := rand(159) xor rand(158) xor rand(141) xor rand(140);
elsif(rand'length = 161) then --161
xor_out := rand(160) xor rand(142);
elsif(rand'length = 162) then --162
xor_out := rand(161) xor rand(160) xor rand(74) xor rand(73);
elsif(rand'length = 163) then --163
xor_out := rand(162) xor rand(161) xor rand(103) xor rand(102);
elsif(rand'length = 164) then --164
xor_out := rand(163) xor rand(162) xor rand(150) xor rand(149);
elsif(rand'length = 165) then --165
xor_out := rand(164) xor rand(163) xor rand(134) xor rand(133);
elsif(rand'length = 166) then --166
xor_out := rand(165) xor rand(164) xor rand(127) xor rand(126);
elsif(rand'length = 167) then --167
xor_out := rand(166) xor rand(160);
elsif(rand'length = 168) then --168
xor_out := rand(167) xor rand(165) xor rand(152) xor rand(150);
end if;
return xor_out;
end xor_gates;
--END function for XORing using tap values.
end lfsr_pkg;
--End of the package.----------------------------------------------------------------------------
---- Create Date: 13:06:08 07/28/2010 ----
---- Design Name: lfsr ----
---- Project Name: lfsr_randgen ----
---- Description: ----
---- A random number generator based on linear feedback shift ----
---- register(LFSR).A LFSR is a shift register whose input bit is a ----
---- linear function of its previous state.The detailed documentation ----
---- is available in the file named manual.pdf. ----
---- ----
----------------------------------------------------------------------------
---- ----
---- This file is a part of the lfsr_randgen project at ----
---- http://www.opencores.org/ ----
---- ----
---- Author(s): ----
---- Vipin Lal, [email protected] ----
---- ----
----------------------------------------------------------------------------
---- ----
---- 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 ----
---- ----
----------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
library work;
use work.lfsr_pkg.ALL;
entity lfsr is
generic (width : integer := 4);
port (clk : in std_logic;
set_seed : in std_logic;
seed : in std_logic_vector(width-1 downto 0);
rand_out : out std_logic_vector(width-1 downto 0)
);
end lfsr;
architecture Behavioral of lfsr is
begin
process(clk)
variable rand_temp : std_logic_vector (width-1 downto 0):=(0 => '1',others => '0');
variable temp : std_logic := '0';
begin
if(rising_edge(clk)) then
if(set_seed = '1') then
rand_temp := seed;
end if;
temp := xor_gates(rand_temp);
rand_temp(width-1 downto 1) := rand_temp(width-2 downto 0);
rand_temp(0) := temp;
end if;
rand_out <= rand_temp;
end process;
end Behavioral;
C语言版本：
#include "stdio.h"
unsigned int k=0;
unsigned int lfsr(unsigned int i)
{
unsigned int t = 0;
unsigned int idc = 0;
unsigned char c[32] = {0};
unsigned int r = 0;
unsigned char xor = 0;
t=i;
idc =0;
printf("\r\n----------%d:\t\r\n",k++);
while(t)
{
if(t%2)
c[idc]=1;
else
c[idc]=0;
idc++;
t>>=1;
// printf("%d",c[idc-1]);
}
while(idc<32)
{
c[idc]=0;
idc++;
// printf("%d",c[idc-1]);
}
//
r = i <<1;
//
idc=0;
xor = c[0]^c[1]^c[21]^c[31];
r+=xor;
printf("\t%d %#x\r\n",xor,r);
//
return r;
}
void main()
{
unsigned int s;
unsigned int t1,t2;
unsigned int id = 0;
printf("hello \r\n");
s= 0x12345678;
printf("%#x %d\r\n",s,sizeof(unsigned int));
t1 = s;
//
FILE* fp;
if ((fp = fopen("./lfsr.txt", "w")) == NULL) {
printf("create file failed！");
return;
}
//
unsigned int cnt =0;
while((t2=lfsr(t1))!=s)
{
//fprintf(fp, "%d\t%#x\n",cnt++, t2);
t1 =t2;
// if(id++ > 100) break;
}
//
fclose(fp);
return;
}
https://www.xilinx.com/support/documentation/application_notes/xapp052.pdf
