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/* ===============================================================
        (C) 2006  Robert Finch
        All rights reserved.
        rob@birdcomputer.ca
 
        cntpop.v
                - count number of one bits in a byte
                - simple fast approach - lookup table
 
        This source code is free for use and modification for
        non-commercial or evaluation purposes, provided this
        copyright statement and disclaimer remains present in
        the file.
 
        If the code is modified, please state the origin and
        note that the code has been modified.
 
        NO WARRANTY.
        THIS Work, IS PROVIDEDED "AS IS" WITH NO WARRANTIES OF
        ANY KIND, WHETHER EXPRESS OR IMPLIED. The user must assume
        the entire risk of using the Work.
 
        IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
        ANY INCIDENTAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES
        WHATSOEVER RELATING TO THE USE OF THIS WORK, OR YOUR
        RELATIONSHIP WITH THE AUTHOR.
 
        IN ADDITION, IN NO EVENT DOES THE AUTHOR AUTHORIZE YOU
        TO USE THE WORK IN APPLICATIONS OR SYSTEMS WHERE THE
        WORK'S FAILURE TO PERFORM CAN REASONABLY BE EXPECTED
        TO RESULT IN A SIGNIFICANT PHYSICAL INJURY, OR IN LOSS
        OF LIFE. ANY SUCH USE BY YOU IS ENTIRELY AT YOUR OWN RISK,
        AND YOU AGREE TO HOLD THE AUTHOR AND CONTRIBUTORS HARMLESS
        FROM ANY CLAIMS OR LOSSES RELATING TO SUCH UNAUTHORIZED
        USE.
 
        Ref: Webpack 8.1i Spartan3-4 xc3s1000-4ft256
        11 LUTs / 6 slices / 12.2 ns
 
=============================================================== */
 
module cntpop8(
        input [7:0] i,
        output reg [3:0] o
);
 
        always @(i)
                case (i)
                8'b00000000:    o = 0;
                8'b00000001:    o = 1;
                8'b00000010:    o = 1;
                8'b00000011:    o = 2;
                8'b00000100:    o = 1;
                8'b00000101:    o = 2;
                8'b00000110:    o = 2;
                8'b00000111:    o = 3;
                8'b00001000:    o = 1;
                8'b00001001:    o = 2;
                8'b00001010:    o = 2;
                8'b00001011:    o = 3;
                8'b00001100:    o = 2;
                8'b00001101:    o = 3;
                8'b00001110:    o = 3;
                8'b00001111:    o = 4;
 
                8'b00010000:    o = 1;
                8'b00010001:    o = 2;
                8'b00010010:    o = 2;
                8'b00010011:    o = 3;
                8'b00010100:    o = 2;
                8'b00010101:    o = 3;
                8'b00010110:    o = 3;
                8'b00010111:    o = 4;
                8'b00011000:    o = 2;
                8'b00011001:    o = 3;
                8'b00011010:    o = 3;
                8'b00011011:    o = 4;
                8'b00011100:    o = 3;
                8'b00011101:    o = 4;
                8'b00011110:    o = 4;
                8'b00011111:    o = 5;
 
                8'b00100000:    o = 1;
                8'b00100001:    o = 2;
                8'b00100010:    o = 2;
                8'b00100011:    o = 3;
                8'b00100100:    o = 2;
                8'b00100101:    o = 3;
                8'b00100110:    o = 3;
                8'b00100111:    o = 4;
                8'b00101000:    o = 2;
                8'b00101001:    o = 3;
                8'b00101010:    o = 3;
                8'b00101011:    o = 4;
                8'b00101100:    o = 3;
                8'b00101101:    o = 4;
                8'b00101110:    o = 4;
                8'b00101111:    o = 5;
 
                8'b00110000:    o = 2;
                8'b00110001:    o = 3;
                8'b00110010:    o = 3;
                8'b00110011:    o = 4;
                8'b00110100:    o = 3;
                8'b00110101:    o = 4;
                8'b00110110:    o = 4;
                8'b00110111:    o = 5;
                8'b00111000:    o = 3;
                8'b00111001:    o = 4;
                8'b00111010:    o = 4;
                8'b00111011:    o = 5;
                8'b00111100:    o = 4;
                8'b00111101:    o = 5;
                8'b00111110:    o = 5;
                8'b00111111:    o = 6;
 
                // 44 - 1       
                8'b01000000:    o = 1;
                8'b01000001:    o = 2;
                8'b01000010:    o = 2;
                8'b01000011:    o = 3;
                8'b01000100:    o = 2;
                8'b01000101:    o = 3;
                8'b01000110:    o = 3;
                8'b01000111:    o = 4;
                8'b01001000:    o = 2;
                8'b01001001:    o = 3;
                8'b01001010:    o = 3;
                8'b01001011:    o = 4;
                8'b01001100:    o = 3;
                8'b01001101:    o = 4;
                8'b01001110:    o = 4;
                8'b01001111:    o = 5;
 
                8'b01010000:    o = 2;
                8'b01010001:    o = 3;
                8'b01010010:    o = 3;
                8'b01010011:    o = 4;
                8'b01010100:    o = 3;
                8'b01010101:    o = 4;
                8'b01010110:    o = 4;
                8'b01010111:    o = 5;
                8'b01011000:    o = 3;
                8'b01011001:    o = 4;
                8'b01011010:    o = 4;
                8'b01011011:    o = 5;
                8'b01011100:    o = 4;
                8'b01011101:    o = 5;
                8'b01011110:    o = 5;
                8'b01011111:    o = 6;
 
                8'b01100000:    o = 2;
                8'b01100001:    o = 3;
                8'b01100010:    o = 3;
                8'b01100011:    o = 4;
                8'b01100100:    o = 3;
                8'b01100101:    o = 4;
                8'b01100110:    o = 4;
                8'b01100111:    o = 5;
                8'b01101000:    o = 3;
                8'b01101001:    o = 4;
                8'b01101010:    o = 4;
                8'b01101011:    o = 5;
                8'b01101100:    o = 4;
                8'b01101101:    o = 5;
                8'b01101110:    o = 5;
                8'b01101111:    o = 6;
 
                8'b01110000:    o = 3;
                8'b01110001:    o = 4;
                8'b01110010:    o = 4;
                8'b01110011:    o = 5;
                8'b01110100:    o = 4;
                8'b01110101:    o = 5;
                8'b01110110:    o = 5;
                8'b01110111:    o = 6;
                8'b01111000:    o = 4;
                8'b01111001:    o = 5;
                8'b01111010:    o = 5;
                8'b01111011:    o = 6;
                8'b01111100:    o = 5;
                8'b01111101:    o = 6;
                8'b01111110:    o = 6;
                8'b01111111:    o = 7;
 
                //  - 2 
                8'b10000000:    o = 1;
                8'b10000001:    o = 2;
                8'b10000010:    o = 2;
                8'b10000011:    o = 3;
                8'b10000100:    o = 2;
                8'b10000101:    o = 3;
                8'b10000110:    o = 3;
                8'b10000111:    o = 4;
                8'b10001000:    o = 2;
                8'b10001001:    o = 3;
                8'b10001010:    o = 3;
                8'b10001011:    o = 4;
                8'b10001100:    o = 3;
                8'b10001101:    o = 4;
                8'b10001110:    o = 4;
                8'b10001111:    o = 5;
 
                8'b10010000:    o = 2;
                8'b10010001:    o = 3;
                8'b10010010:    o = 3;
                8'b10010011:    o = 4;
                8'b10010100:    o = 3;
                8'b10010101:    o = 4;
                8'b10010110:    o = 4;
                8'b10010111:    o = 5;
                8'b10011000:    o = 3;
                8'b10011001:    o = 4;
                8'b10011010:    o = 4;
                8'b10011011:    o = 5;
                8'b10011100:    o = 4;
                8'b10011101:    o = 5;
                8'b10011110:    o = 5;
                8'b10011111:    o = 6;
 
                8'b10100000:    o = 2;
                8'b10100001:    o = 3;
                8'b10100010:    o = 3;
                8'b10100011:    o = 4;
                8'b10100100:    o = 3;
                8'b10100101:    o = 4;
                8'b10100110:    o = 4;
                8'b10100111:    o = 5;
                8'b10101000:    o = 3;
                8'b10101001:    o = 4;
                8'b10101010:    o = 4;
                8'b10101011:    o = 5;
                8'b10101100:    o = 4;
                8'b10101101:    o = 5;
                8'b10101110:    o = 5;
                8'b10101111:    o = 6;
 
                8'b10110000:    o = 3;
                8'b10110001:    o = 4;
                8'b10110010:    o = 4;
                8'b10110011:    o = 5;
                8'b10110100:    o = 4;
                8'b10110101:    o = 5;
                8'b10110110:    o = 5;
                8'b10110111:    o = 6;
                8'b10111000:    o = 4;
                8'b10111001:    o = 5;
                8'b10111010:    o = 5;
                8'b10111011:    o = 6;
                8'b10111100:    o = 5;
                8'b10111101:    o = 6;
                8'b10111110:    o = 6;
                8'b10111111:    o = 7;
 
                // 44 - 3       
                8'b11000000:    o = 2;
                8'b11000001:    o = 3;
                8'b11000010:    o = 3;
                8'b11000011:    o = 4;
                8'b11000100:    o = 3;
                8'b11000101:    o = 4;
                8'b11000110:    o = 4;
                8'b11000111:    o = 5;
                8'b11001000:    o = 3;
                8'b11001001:    o = 4;
                8'b11001010:    o = 4;
                8'b11001011:    o = 5;
                8'b11001100:    o = 4;
                8'b11001101:    o = 5;
                8'b11001110:    o = 5;
                8'b11001111:    o = 6;
 
                8'b11010000:    o = 3;
                8'b11010001:    o = 4;
                8'b11010010:    o = 4;
                8'b11010011:    o = 5;
                8'b11010100:    o = 4;
                8'b11010101:    o = 5;
                8'b11010110:    o = 5;
                8'b11010111:    o = 6;
                8'b11011000:    o = 4;
                8'b11011001:    o = 5;
                8'b11011010:    o = 5;
                8'b11011011:    o = 6;
                8'b11011100:    o = 5;
                8'b11011101:    o = 6;
                8'b11011110:    o = 6;
                8'b11011111:    o = 7;
 
                8'b11100000:    o = 3;
                8'b11100001:    o = 4;
                8'b11100010:    o = 4;
                8'b11100011:    o = 5;
                8'b11100100:    o = 4;
                8'b11100101:    o = 5;
                8'b11100110:    o = 5;
                8'b11100111:    o = 6;
                8'b11101000:    o = 4;
                8'b11101001:    o = 5;
                8'b11101010:    o = 5;
                8'b11101011:    o = 6;
                8'b11101100:    o = 5;
                8'b11101101:    o = 6;
                8'b11101110:    o = 6;
                8'b11101111:    o = 7;
 
                8'b11110000:    o = 4;
                8'b11110001:    o = 5;
                8'b11110010:    o = 5;
                8'b11110011:    o = 6;
                8'b11110100:    o = 5;
                8'b11110101:    o = 6;
                8'b11110110:    o = 6;
                8'b11110111:    o = 7;
                8'b11111000:    o = 5;
                8'b11111001:    o = 6;
                8'b11111010:    o = 6;
                8'b11111011:    o = 7;
                8'b11111100:    o = 6;
                8'b11111101:    o = 7;
                8'b11111110:    o = 7;
                8'b11111111:    o = 8;
 
                endcase
 
 
endmodule
 
 
module cntpop16(
        input [15:0] i,
        output [4:0] o
);
 
        wire [3:0] cnt1, cnt2;
 
        cntpop8 u1 (i[ 7:0],cnt1);
        cntpop8 u2 (i[15:8],cnt2);
 
        assign o = cnt1 + cnt2;
 
endmodule
 
 
// 76 slices / 147 LUTs / 19 ns
module cntpop32(
        input [31:0] i,
        output [5:0] o
);
 
        wire [3:0] cnt1, cnt2, cnt3, cnt4;
 
        // cntpop8 results in faster result than cntpop16
        cntpop8 u1 (i[ 7: 0],cnt1);
        cntpop8 u2 (i[15: 8],cnt2);
        cntpop8 u3 (i[23:16],cnt3);
        cntpop8 u4 (i[31:24],cnt4);
 
        assign o = cnt1+cnt2+cnt3+cnt4;
 
endmodule
 
 
// 156 slices / 300 LUTs / 22.2 ns
module cntpop64(
        input [63:0] i,
        output [6:0] o
);
 
        wire [4:0] cnt1, cnt2, cnt3, cnt4;
 
        cntpop16 u1 (i[15: 0],cnt1);
        cntpop16 u2 (i[31:16],cnt2);
        cntpop16 u3 (i[47:32],cnt3);
        cntpop16 u4 (i[63:48],cnt4);
 
        assign o = cnt1+cnt2+cnt3+cnt4;
 
endmodule
 
 

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[/] [thor/] [trunk/] [rtl/] [verilog/] [lib/] [cntpop.v] - Blame information for rev 7

Line No.	Rev	Author	Line
1	7	robfinch	`/* ===============================================================`
2			`(C) 2006 Robert Finch`
3			`All rights reserved.`
4			`rob@birdcomputer.ca`
5
6			`cntpop.v`
7			`- count number of one bits in a byte`
8			`- simple fast approach - lookup table`
9
10			`This source code is free for use and modification for`
11			`non-commercial or evaluation purposes, provided this`
12			`copyright statement and disclaimer remains present in`
13			`the file.`
14
15			`If the code is modified, please state the origin and`
16			`note that the code has been modified.`
17
18			`NO WARRANTY.`
19			`THIS Work, IS PROVIDEDED "AS IS" WITH NO WARRANTIES OF`
20			`ANY KIND, WHETHER EXPRESS OR IMPLIED. The user must assume`
21			`the entire risk of using the Work.`
22
23			`IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR`
24			`ANY INCIDENTAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES`
25			`WHATSOEVER RELATING TO THE USE OF THIS WORK, OR YOUR`
26			`RELATIONSHIP WITH THE AUTHOR.`
27
28			`IN ADDITION, IN NO EVENT DOES THE AUTHOR AUTHORIZE YOU`
29			`TO USE THE WORK IN APPLICATIONS OR SYSTEMS WHERE THE`
30			`WORK'S FAILURE TO PERFORM CAN REASONABLY BE EXPECTED`
31			`TO RESULT IN A SIGNIFICANT PHYSICAL INJURY, OR IN LOSS`
32			`OF LIFE. ANY SUCH USE BY YOU IS ENTIRELY AT YOUR OWN RISK,`
33			`AND YOU AGREE TO HOLD THE AUTHOR AND CONTRIBUTORS HARMLESS`
34			`FROM ANY CLAIMS OR LOSSES RELATING TO SUCH UNAUTHORIZED`
35			`USE.`
36
37			`Ref: Webpack 8.1i Spartan3-4 xc3s1000-4ft256`
38			`11 LUTs / 6 slices / 12.2 ns`
39
40			`=============================================================== */`
41
42			`module cntpop8(`
43			`input [7:0] i,`
44			`output reg [3:0] o`
45			`);`
46
47			`always @(i)`
48			`case (i)`
49			`8'b00000000: o = 0;`
50			`8'b00000001: o = 1;`
51			`8'b00000010: o = 1;`
52			`8'b00000011: o = 2;`
53			`8'b00000100: o = 1;`
54			`8'b00000101: o = 2;`
55			`8'b00000110: o = 2;`
56			`8'b00000111: o = 3;`
57			`8'b00001000: o = 1;`
58			`8'b00001001: o = 2;`
59			`8'b00001010: o = 2;`
60			`8'b00001011: o = 3;`
61			`8'b00001100: o = 2;`
62			`8'b00001101: o = 3;`
63			`8'b00001110: o = 3;`
64			`8'b00001111: o = 4;`
65
66			`8'b00010000: o = 1;`
67			`8'b00010001: o = 2;`
68			`8'b00010010: o = 2;`
69			`8'b00010011: o = 3;`
70			`8'b00010100: o = 2;`
71			`8'b00010101: o = 3;`
72			`8'b00010110: o = 3;`
73			`8'b00010111: o = 4;`
74			`8'b00011000: o = 2;`
75			`8'b00011001: o = 3;`
76			`8'b00011010: o = 3;`
77			`8'b00011011: o = 4;`
78			`8'b00011100: o = 3;`
79			`8'b00011101: o = 4;`
80			`8'b00011110: o = 4;`
81			`8'b00011111: o = 5;`
82
83			`8'b00100000: o = 1;`
84			`8'b00100001: o = 2;`
85			`8'b00100010: o = 2;`
86			`8'b00100011: o = 3;`
87			`8'b00100100: o = 2;`
88			`8'b00100101: o = 3;`
89			`8'b00100110: o = 3;`
90			`8'b00100111: o = 4;`
91			`8'b00101000: o = 2;`
92			`8'b00101001: o = 3;`
93			`8'b00101010: o = 3;`
94			`8'b00101011: o = 4;`
95			`8'b00101100: o = 3;`
96			`8'b00101101: o = 4;`
97			`8'b00101110: o = 4;`
98			`8'b00101111: o = 5;`
99
100			`8'b00110000: o = 2;`
101			`8'b00110001: o = 3;`
102			`8'b00110010: o = 3;`
103			`8'b00110011: o = 4;`
104			`8'b00110100: o = 3;`
105			`8'b00110101: o = 4;`
106			`8'b00110110: o = 4;`
107			`8'b00110111: o = 5;`
108			`8'b00111000: o = 3;`
109			`8'b00111001: o = 4;`
110			`8'b00111010: o = 4;`
111			`8'b00111011: o = 5;`
112			`8'b00111100: o = 4;`
113			`8'b00111101: o = 5;`
114			`8'b00111110: o = 5;`
115			`8'b00111111: o = 6;`
116
117			`// 44 - 1`
118			`8'b01000000: o = 1;`
119			`8'b01000001: o = 2;`
120			`8'b01000010: o = 2;`
121			`8'b01000011: o = 3;`
122			`8'b01000100: o = 2;`
123			`8'b01000101: o = 3;`
124			`8'b01000110: o = 3;`
125			`8'b01000111: o = 4;`
126			`8'b01001000: o = 2;`
127			`8'b01001001: o = 3;`
128			`8'b01001010: o = 3;`
129			`8'b01001011: o = 4;`
130			`8'b01001100: o = 3;`
131			`8'b01001101: o = 4;`
132			`8'b01001110: o = 4;`
133			`8'b01001111: o = 5;`
134
135			`8'b01010000: o = 2;`
136			`8'b01010001: o = 3;`
137			`8'b01010010: o = 3;`
138			`8'b01010011: o = 4;`
139			`8'b01010100: o = 3;`
140			`8'b01010101: o = 4;`
141			`8'b01010110: o = 4;`
142			`8'b01010111: o = 5;`
143			`8'b01011000: o = 3;`
144			`8'b01011001: o = 4;`
145			`8'b01011010: o = 4;`
146			`8'b01011011: o = 5;`
147			`8'b01011100: o = 4;`
148			`8'b01011101: o = 5;`
149			`8'b01011110: o = 5;`
150			`8'b01011111: o = 6;`
151
152			`8'b01100000: o = 2;`
153			`8'b01100001: o = 3;`
154			`8'b01100010: o = 3;`
155			`8'b01100011: o = 4;`
156			`8'b01100100: o = 3;`
157			`8'b01100101: o = 4;`
158			`8'b01100110: o = 4;`
159			`8'b01100111: o = 5;`
160			`8'b01101000: o = 3;`
161			`8'b01101001: o = 4;`
162			`8'b01101010: o = 4;`
163			`8'b01101011: o = 5;`
164			`8'b01101100: o = 4;`
165			`8'b01101101: o = 5;`
166			`8'b01101110: o = 5;`
167			`8'b01101111: o = 6;`
168
169			`8'b01110000: o = 3;`
170			`8'b01110001: o = 4;`
171			`8'b01110010: o = 4;`
172			`8'b01110011: o = 5;`
173			`8'b01110100: o = 4;`
174			`8'b01110101: o = 5;`
175			`8'b01110110: o = 5;`
176			`8'b01110111: o = 6;`
177			`8'b01111000: o = 4;`
178			`8'b01111001: o = 5;`
179			`8'b01111010: o = 5;`
180			`8'b01111011: o = 6;`
181			`8'b01111100: o = 5;`
182			`8'b01111101: o = 6;`
183			`8'b01111110: o = 6;`
184			`8'b01111111: o = 7;`
185
186			`// - 2`
187			`8'b10000000: o = 1;`
188			`8'b10000001: o = 2;`
189			`8'b10000010: o = 2;`
190			`8'b10000011: o = 3;`
191			`8'b10000100: o = 2;`
192			`8'b10000101: o = 3;`
193			`8'b10000110: o = 3;`
194			`8'b10000111: o = 4;`
195			`8'b10001000: o = 2;`
196			`8'b10001001: o = 3;`
197			`8'b10001010: o = 3;`
198			`8'b10001011: o = 4;`
199			`8'b10001100: o = 3;`
200			`8'b10001101: o = 4;`
201			`8'b10001110: o = 4;`
202			`8'b10001111: o = 5;`
203
204			`8'b10010000: o = 2;`
205			`8'b10010001: o = 3;`
206			`8'b10010010: o = 3;`
207			`8'b10010011: o = 4;`
208			`8'b10010100: o = 3;`
209			`8'b10010101: o = 4;`
210			`8'b10010110: o = 4;`
211			`8'b10010111: o = 5;`
212			`8'b10011000: o = 3;`
213			`8'b10011001: o = 4;`
214			`8'b10011010: o = 4;`
215			`8'b10011011: o = 5;`
216			`8'b10011100: o = 4;`
217			`8'b10011101: o = 5;`
218			`8'b10011110: o = 5;`
219			`8'b10011111: o = 6;`
220
221			`8'b10100000: o = 2;`
222			`8'b10100001: o = 3;`
223			`8'b10100010: o = 3;`
224			`8'b10100011: o = 4;`
225			`8'b10100100: o = 3;`
226			`8'b10100101: o = 4;`
227			`8'b10100110: o = 4;`
228			`8'b10100111: o = 5;`
229			`8'b10101000: o = 3;`
230			`8'b10101001: o = 4;`
231			`8'b10101010: o = 4;`
232			`8'b10101011: o = 5;`
233			`8'b10101100: o = 4;`
234			`8'b10101101: o = 5;`
235			`8'b10101110: o = 5;`
236			`8'b10101111: o = 6;`
237
238			`8'b10110000: o = 3;`
239			`8'b10110001: o = 4;`
240			`8'b10110010: o = 4;`
241			`8'b10110011: o = 5;`
242			`8'b10110100: o = 4;`
243			`8'b10110101: o = 5;`
244			`8'b10110110: o = 5;`
245			`8'b10110111: o = 6;`
246			`8'b10111000: o = 4;`
247			`8'b10111001: o = 5;`
248			`8'b10111010: o = 5;`
249			`8'b10111011: o = 6;`
250			`8'b10111100: o = 5;`
251			`8'b10111101: o = 6;`
252			`8'b10111110: o = 6;`
253			`8'b10111111: o = 7;`
254
255			`// 44 - 3`
256			`8'b11000000: o = 2;`
257			`8'b11000001: o = 3;`
258			`8'b11000010: o = 3;`
259			`8'b11000011: o = 4;`
260			`8'b11000100: o = 3;`
261			`8'b11000101: o = 4;`
262			`8'b11000110: o = 4;`
263			`8'b11000111: o = 5;`
264			`8'b11001000: o = 3;`
265			`8'b11001001: o = 4;`
266			`8'b11001010: o = 4;`
267			`8'b11001011: o = 5;`
268			`8'b11001100: o = 4;`
269			`8'b11001101: o = 5;`
270			`8'b11001110: o = 5;`
271			`8'b11001111: o = 6;`
272
273			`8'b11010000: o = 3;`
274			`8'b11010001: o = 4;`
275			`8'b11010010: o = 4;`
276			`8'b11010011: o = 5;`
277			`8'b11010100: o = 4;`
278			`8'b11010101: o = 5;`
279			`8'b11010110: o = 5;`
280			`8'b11010111: o = 6;`
281			`8'b11011000: o = 4;`
282			`8'b11011001: o = 5;`
283			`8'b11011010: o = 5;`
284			`8'b11011011: o = 6;`
285			`8'b11011100: o = 5;`
286			`8'b11011101: o = 6;`
287			`8'b11011110: o = 6;`
288			`8'b11011111: o = 7;`
289
290			`8'b11100000: o = 3;`
291			`8'b11100001: o = 4;`
292			`8'b11100010: o = 4;`
293			`8'b11100011: o = 5;`
294			`8'b11100100: o = 4;`
295			`8'b11100101: o = 5;`
296			`8'b11100110: o = 5;`
297			`8'b11100111: o = 6;`
298			`8'b11101000: o = 4;`
299			`8'b11101001: o = 5;`
300			`8'b11101010: o = 5;`
301			`8'b11101011: o = 6;`
302			`8'b11101100: o = 5;`
303			`8'b11101101: o = 6;`
304			`8'b11101110: o = 6;`
305			`8'b11101111: o = 7;`
306
307			`8'b11110000: o = 4;`
308			`8'b11110001: o = 5;`
309			`8'b11110010: o = 5;`
310			`8'b11110011: o = 6;`
311			`8'b11110100: o = 5;`
312			`8'b11110101: o = 6;`
313			`8'b11110110: o = 6;`
314			`8'b11110111: o = 7;`
315			`8'b11111000: o = 5;`
316			`8'b11111001: o = 6;`
317			`8'b11111010: o = 6;`
318			`8'b11111011: o = 7;`
319			`8'b11111100: o = 6;`
320			`8'b11111101: o = 7;`
321			`8'b11111110: o = 7;`
322			`8'b11111111: o = 8;`
323
324			`endcase`
325
326
327			`endmodule`
328
329
330			`module cntpop16(`
331			`input [15:0] i,`
332			`output [4:0] o`
333			`);`
334
335			`wire [3:0] cnt1, cnt2;`
336
337			`cntpop8 u1 (i[ 7:0],cnt1);`
338			`cntpop8 u2 (i[15:8],cnt2);`
339
340			`assign o = cnt1 + cnt2;`
341
342			`endmodule`
343
344
345			`// 76 slices / 147 LUTs / 19 ns`
346			`module cntpop32(`
347			`input [31:0] i,`
348			`output [5:0] o`
349			`);`
350
351			`wire [3:0] cnt1, cnt2, cnt3, cnt4;`
352
353			`// cntpop8 results in faster result than cntpop16`
354			`cntpop8 u1 (i[ 7: 0],cnt1);`
355			`cntpop8 u2 (i[15: 8],cnt2);`
356			`cntpop8 u3 (i[23:16],cnt3);`
357			`cntpop8 u4 (i[31:24],cnt4);`
358
359			`assign o = cnt1+cnt2+cnt3+cnt4;`
360
361			`endmodule`
362
363
364			`// 156 slices / 300 LUTs / 22.2 ns`
365			`module cntpop64(`
366			`input [63:0] i,`
367			`output [6:0] o`
368			`);`
369
370			`wire [4:0] cnt1, cnt2, cnt3, cnt4;`
371
372			`cntpop16 u1 (i[15: 0],cnt1);`
373			`cntpop16 u2 (i[31:16],cnt2);`
374			`cntpop16 u3 (i[47:32],cnt3);`
375			`cntpop16 u4 (i[63:48],cnt4);`
376
377			`assign o = cnt1+cnt2+cnt3+cnt4;`
378
379			`endmodule`
380
381