3 // USRP - Universal Software Radio Peripheral
5 // Copyright (C) 2005,2006 Matt Ettus
7 // This program is free software; you can redistribute it and/or modify
8 // it under the terms of the GNU General Public License as published by
9 // the Free Software Foundation; either version 2 of the License, or
10 // (at your option) any later version.
12 // This program is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Boston, MA 02110-1301 USA
22 module shifter(input wire [33:0] in, output wire [15:0] out, input wire [7:0] shift);
23 // Wish we could do assign out = in[15+shift:shift];
25 reg [15:0] quotient, remainder;
26 wire [15:0] out_unclipped;
32 0 : quotient = in[15:0];
33 1 : quotient = in[16:1];
34 2 : quotient = in[17:2];
35 3 : quotient = in[18:3];
36 4 : quotient = in[19:4];
37 5 : quotient = in[20:5];
38 6 : quotient = in[21:6];
39 7 : quotient = in[22:7];
40 8 : quotient = in[23:8];
41 9 : quotient = in[24:9];
42 10 : quotient = in[25:10];
43 11 : quotient = in[26:11];
44 12 : quotient = in[27:12];
45 13 : quotient = in[28:13];
46 14 : quotient = in[29:14];
47 15 : quotient = in[30:15];
48 16 : quotient = in[31:16];
49 17 : quotient = in[32:17];
50 18 : quotient = in[33:18];
51 default : quotient = in[15:0];
52 endcase // case(shift)
56 0 : remainder = 16'b0;
57 1 : remainder = {in[0],15'b0};
58 2 : remainder = {in[1:0],14'b0};
59 3 : remainder = {in[2:0],13'b0};
60 4 : remainder = {in[3:0],12'b0};
61 5 : remainder = {in[4:0],11'b0};
62 6 : remainder = {in[5:0],10'b0};
63 7 : remainder = {in[6:0],9'b0};
64 8 : remainder = {in[7:0],8'b0};
65 9 : remainder = {in[8:0],7'b0};
66 10 : remainder = {in[9:0],6'b0};
67 11 : remainder = {in[10:0],5'b0};
68 12 : remainder = {in[11:0],4'b0};
69 13 : remainder = {in[12:0],3'b0};
70 14 : remainder = {in[13:0],2'b0};
71 15 : remainder = {in[14:0],1'b0};
72 16 : remainder = in[15:0];
73 17 : remainder = in[16:1];
74 18 : remainder = in[17:2];
75 default : remainder = 16'b0;
76 endcase // case(shift)
81 1 : msbs = {in[33],in[33:16]};
82 2 : msbs = {{2{in[33]}},in[33:17]};
83 3 : msbs = {{3{in[33]}},in[33:18]};
84 4 : msbs = {{4{in[33]}},in[33:19]};
85 5 : msbs = {{5{in[33]}},in[33:20]};
86 6 : msbs = {{6{in[33]}},in[33:21]};
87 7 : msbs = {{7{in[33]}},in[33:22]};
88 8 : msbs = {{8{in[33]}},in[33:23]};
89 9 : msbs = {{9{in[33]}},in[33:24]};
90 10 : msbs = {{10{in[33]}},in[33:25]};
91 11 : msbs = {{11{in[33]}},in[33:26]};
92 12 : msbs = {{12{in[33]}},in[33:27]};
93 13 : msbs = {{13{in[33]}},in[33:28]};
94 14 : msbs = {{14{in[33]}},in[33:29]};
95 15 : msbs = {{15{in[33]}},in[33:30]};
96 16 : msbs = {{16{in[33]}},in[33:31]};
97 17 : msbs = {{17{in[33]}},in[33:32]};
98 18 : msbs = {{18{in[33]}},in[33]};
99 default : msbs = in[33:15];
100 endcase // case(shift)
102 assign in_range = &msbs | ~(|msbs);
103 assign out_unclipped = quotient + (in[33] & |remainder);
104 assign out = in_range ? out_unclipped : {in[33],{15{~in[33]}}};