Entity: arith_prng

Diagram

positive BITS std_logic_vector SEED std_logic clk std_logic rst std_logic got std_logic_vector(BITS - 1 downto 0) val

Description

EMACS settings: -- tab-width: 2; indent-tabs-mode: t -- vim: tabstop=2:shiftwidth=2:noexpandtab

kate: tab-width 2; replace-tabs off; indent-width 2;

Authors: Martin Zabel Patrick Lehmann

Entity: Pseudo-Random Number Generator (PRNG).

Description:

This module implementes a Pseudo-Random Number Generator (PRNG) with configurable bit count (BITS). This module uses an internal list of FPGA optimized polynomials from 3 to 168 bits. The polynomials have at most 5 tap positions, so that long shift registers can be inferred instead of single flip-flops.

The generated number sequence includes the value all-zeros, but not all-ones.

License:

Copyright 2007-2014 Technische Universitaet Dresden - Germany Chair of VLSI-Design, Diagnostics and Architecture

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and

limitations under the License.

Generics

Generic name Type Value Description
BITS positive 32
SEED std_logic_vector "0"

Ports

Port name Direction Type Description
clk in std_logic
rst in std_logic reset value to initial seed
got in std_logic the current value has been got, and a new value should be calculated
val out std_logic_vector(BITS - 1 downto 0) the pseudo-random number

Signals

Name Type Description
bit1_nxt std_logic The current value
val_r std_logic_vector(BITS downto 1)

Constants

Name Type Value Description
C_TAPPOSITION_LIST T_TAPPOSITION_VECTOR(3 to 168) ( 3 => (0 => 2,
others => 0),
4 => (0 => 3,
others => 0),
5 => (0 => 3,
others => 0),
6 => (0 => 5,
others => 0),
7 => (0 => 6,
others => 0),
8 => (0 => 6,
1 => 5,
2 => 4,
others => 0),
9 => (0 => 5,
others => 0),
10 => (0 => 7,
others => 0),
11 => (0 => 9,
others => 0),
12 => (0 => 6,
1 => 4,
2 => 1,
others => 0),
13 => (0 => 4,
1 => 3,
2 => 1,
others => 0),
14 => (0 => 5,
1 => 3,
2 => 1,
others => 0),
15 => (0 => 14,
others => 0),
16 => (0 => 15,
1 => 13,
2 => 4,
others => 0),
17 => (0 => 14,
others => 0),
18 => (0 => 11,
others => 0),
19 => (0 => 6,
1 => 2,
2 => 1,
others => 0),
20 => (0 => 17,
others => 0),
21 => (0 => 19,
others => 0),
22 => (0 => 21,
others => 0),
23 => (0 => 18,
others => 0),
24 => (0 => 23,
1 => 22,
2 => 17,
others => 0),
25 => (0 => 22,
others => 0),
26 => (0 => 6,
1 => 2,
2 => 1,
others => 0),
27 => (0 => 5,
1 => 2,
2 => 1,
others => 0),
28 => (0 => 25,
others => 0),
29 => (0 => 27,
others => 0),
30 => (0 => 6,
1 => 4,
2 => 1,
others => 0),
31 => (0 => 28,
others => 0),
32 => (0 => 22,
1 => 2,
2 => 1,
others => 0),
33 => (0 => 2,
others => 0),
34 => (0 => 27,
1 => 2,
2 => 1,
others => 0),
35 => (0 => 33,
others => 0),
36 => (0 => 25,
others => 0),
37 => (0 => 5,
1 => 4,
2 => 3,
3 => 2,
4 => 1),
38 => (0 => 6,
1 => 5,
2 => 1,
others => 0),
39 => (0 => 35,
others => 0),
40 => (0 => 38,
1 => 21,
2 => 19,
others => 0),
41 => (0 => 38,
others => 0),
42 => (0 => 41,
1 => 20,
2 => 19,
others => 0),
43 => (0 => 42,
1 => 38,
2 => 37,
others => 0),
44 => (0 => 43,
1 => 18,
2 => 17,
others => 0),
45 => (0 => 44,
1 => 42,
2 => 41,
others => 0),
46 => (0 => 45,
1 => 26,
2 => 25,
others => 0),
47 => (0 => 42,
others => 0),
48 => (0 => 47,
1 => 21,
2 => 20,
others => 0),
49 => (0 => 4,
others => 0),
50 => (0 => 49,
1 => 24,
2 => 23,
others => 0),
51 => (0 => 50,
1 => 36,
2 => 35,
others => 0),
52 => (0 => 49,
others => 0),
53 => (0 => 52,
1 => 38,
2 => 37,
others => 0),
54 => (0 => 53,
1 => 18,
2 => 17,
others => 0),
55 => (0 => 31,
others => 0),
56 => (0 => 55,
1 => 35,
2 => 34,
others => 0),
57 => (0 => 5,
others => 0),
58 => (0 => 39,
others => 0),
59 => (0 => 58,
1 => 38,
2 => 37,
others => 0),
60 => (0 => 59,
others => 0),
61 => (0 => 60,
1 => 46,
2 => 45,
others => 0),
62 => (0 => 61,
1 => 6,
2 => 5,
others => 0),
63 => (0 => 62,
others => 0),
64 => (0 => 63,
1 => 61,
2 => 60,
others => 0),
65 => (0 => 47,
others => 0),
66 => (0 => 65,
1 => 57,
2 => 56,
others => 0),
67 => (0 => 66,
1 => 58,
2 => 57,
others => 0),
68 => (0 => 59,
others => 0),
69 => (0 => 67,
1 => 42,
2 => 40,
others => 0),
70 => (0 => 69,
1 => 55,
2 => 54,
others => 0),
71 => (0 => 65,
others => 0),
72 => (0 => 66,
1 => 25,
2 => 19,
others => 0),
73 => (0 => 48,
others => 0),
74 => (0 => 73,
1 => 59,
2 => 58,
others => 0),
75 => (0 => 74,
1 => 65,
2 => 64,
others => 0),
76 => (0 => 75,
1 => 41,
2 => 40,
others => 0),
77 => (0 => 76,
1 => 47,
2 => 46,
others => 0),
78 => (0 => 77,
1 => 59,
2 => 58,
others => 0),
79 => (0 => 7,
others => 0),
80 => (0 => 79,
1 => 43,
2 => 42,
others => 0),
81 => (0 => 77,
others => 0),
82 => (0 => 79,
1 => 47,
2 => 44,
others => 0),
83 => (0 => 82,
1 => 38,
2 => 37,
others => 0),
84 => (0 => 71,
others => 0),
85 => (0 => 84,
1 => 58,
2 => 57,
others => 0),
86 => (0 => 85,
1 => 74,
2 => 73,
others => 0),
87 => (0 => 74,
others => 0),
88 => (0 => 87,
1 => 17,
2 => 16,
others => 0),
89 => (0 => 51,
others => 0),
90 => (0 => 89,
1 => 72,
2 => 71,
others => 0),
91 => (0 => 90,
1 => 8,
2 => 7,
others => 0),
92 => (0 => 91,
1 => 80,
2 => 79,
others => 0),
93 => (0 => 91,
others => 0),
94 => (0 => 73,
others => 0),
95 => (0 => 84,
others => 0),
96 => (0 => 94,
1 => 49,
2 => 47,
others => 0),
97 => (0 => 91,
others => 0),
98 => (0 => 87,
others => 0),
99 => (0 => 97,
1 => 54,
2 => 52,
others => 0),
100 => (0 => 63,
others => 0),
101 => (0 => 100,
1 => 95,
2 => 94,
others => 0),
102 => (0 => 101,
1 => 36,
2 => 35,
others => 0),
103 => (0 => 94,
others => 0),
104 => (0 => 103,
1 => 94,
2 => 93,
others => 0),
105 => (0 => 89,
others => 0),
106 => (0 => 91,
others => 0),
107 => (0 => 105,
1 => 44,
2 => 42,
others => 0),
108 => (0 => 77,
others => 0),
109 => (0 => 108,
1 => 103,
2 => 102,
others => 0),
110 => (0 => 109,
1 => 98,
2 => 97,
others => 0),
111 => (0 => 101,
others => 0),
112 => (0 => 110,
1 => 69,
2 => 67,
others => 0),
113 => (0 => 104,
others => 0),
114 => (0 => 113,
1 => 33,
2 => 32,
others => 0),
115 => (0 => 114,
1 => 101,
2 => 100,
others => 0),
116 => (0 => 115,
1 => 46,
2 => 45,
others => 0),
117 => (0 => 115,
1 => 99,
2 => 97,
others => 0),
118 => (0 => 85,
others => 0),
119 => (0 => 111,
others => 0),
120 => (0 => 113,
1 => 9,
2 => 2,
others => 0),
121 => (0 => 103,
others => 0),
122 => (0 => 121,
1 => 63,
2 => 62,
others => 0),
123 => (0 => 121,
others => 0),
124 => (0 => 87,
others => 0),
125 => (0 => 124,
1 => 18,
2 => 17,
others => 0),
126 => (0 => 125,
1 => 90,
2 => 89,
others => 0),
127 => (0 => 126,
others => 0),
128 => (0 => 126,
1 => 101,
2 => 99,
others => 0),
129 => (0 => 124,
others => 0),
130 => (0 => 127,
others => 0),
131 => (0 => 130,
1 => 84,
2 => 83,
others => 0),
132 => (0 => 103,
others => 0),
133 => (0 => 132,
1 => 82,
2 => 81,
others => 0),
134 => (0 => 77,
others => 0),
135 => (0 => 124,
others => 0),
136 => (0 => 135,
1 => 11,
2 => 10,
others => 0),
137 => (0 => 116,
others => 0),
138 => (0 => 137,
1 => 131,
2 => 130,
others => 0),
139 => (0 => 136,
1 => 134,
2 => 131,
others => 0),
140 => (0 => 111,
others => 0),
141 => (0 => 140,
1 => 110,
2 => 109,
others => 0),
142 => (0 => 121,
others => 0),
143 => (0 => 142,
1 => 123,
2 => 122,
others => 0),
144 => (0 => 143,
1 => 75,
2 => 74,
others => 0),
145 => (0 => 93,
others => 0),
146 => (0 => 145,
1 => 87,
2 => 86,
others => 0),
147 => (0 => 146,
1 => 110,
2 => 109,
others => 0),
148 => (0 => 121,
others => 0),
149 => (0 => 148,
1 => 40,
2 => 39,
others => 0),
150 => (0 => 97,
others => 0),
151 => (0 => 148,
others => 0),
152 => (0 => 151,
1 => 87,
2 => 86,
others => 0),
153 => (0 => 152,
others => 0),
154 => (0 => 152,
1 => 27,
2 => 25,
others => 0),
155 => (0 => 154,
1 => 124,
2 => 123,
others => 0),
156 => (0 => 155,
1 => 41,
2 => 40,
others => 0),
157 => (0 => 156,
1 => 131,
2 => 130,
others => 0),
158 => (0 => 157,
1 => 132,
2 => 131,
others => 0),
159 => (0 => 128,
others => 0),
160 => (0 => 159,
1 => 142,
2 => 141,
others => 0),
161 => (0 => 143,
others => 0),
162 => (0 => 161,
1 => 75,
2 => 74,
others => 0),
163 => (0 => 162,
1 => 104,
2 => 103,
others => 0),
164 => (0 => 163,
1 => 151,
2 => 150,
others => 0),
165 => (0 => 164,
1 => 135,
2 => 134,
others => 0),
166 => (0 => 165,
1 => 128,
2 => 127,
others => 0),
167 => (0 => 161,
others => 0),
168 => (0 => 166,
1 => 153,
2 => 151,
others => 0) )		 Tap positions are taken from Xilinx Application Note 052 (XAPP052)
C_TAPPOSITIONS T_TAPPOSITION C_TAPPOSITION_LIST(BITS)

Types

Name Type Description
T_TAPPOSITION_VECTOR array (natural range <>) of T_TAPPOSITION

Processes

Description
--------------------------------------------------------------------------- Datapath --------------------------------------------------------------------------- XNOR used so that all-zero is valid and all-one is forbidden.

Description
--------------------------------------------------------------------------- Register ---------------------------------------------------------------------------