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Diffstat (limited to 'fpga/usrp1/toplevel/mrfm/shifter.v')
| -rw-r--r-- | fpga/usrp1/toplevel/mrfm/shifter.v | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/fpga/usrp1/toplevel/mrfm/shifter.v b/fpga/usrp1/toplevel/mrfm/shifter.v new file mode 100644 index 000000000..dd4d4b527 --- /dev/null +++ b/fpga/usrp1/toplevel/mrfm/shifter.v @@ -0,0 +1,106 @@ +// -*- verilog -*- +// +// USRP - Universal Software Radio Peripheral +// +// Copyright (C) 2005,2006 Matt Ettus +// +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 2 of the License, or +// (at your option) any later version. +// +// This program 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 General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street, Boston, MA 02110-1301 USA +// + +module shifter(input wire [33:0] in, output wire [15:0] out, input wire [7:0] shift); + // Wish we could do assign out = in[15+shift:shift]; + + reg [15:0] quotient, remainder; + wire [15:0] out_unclipped; + reg [18:0] msbs; + wire in_range; + + always @* + case(shift) + 0 : quotient = in[15:0]; + 1 : quotient = in[16:1]; + 2 : quotient = in[17:2]; + 3 : quotient = in[18:3]; + 4 : quotient = in[19:4]; + 5 : quotient = in[20:5]; + 6 : quotient = in[21:6]; + 7 : quotient = in[22:7]; + 8 : quotient = in[23:8]; + 9 : quotient = in[24:9]; + 10 : quotient = in[25:10]; + 11 : quotient = in[26:11]; + 12 : quotient = in[27:12]; + 13 : quotient = in[28:13]; + 14 : quotient = in[29:14]; + 15 : quotient = in[30:15]; + 16 : quotient = in[31:16]; + 17 : quotient = in[32:17]; + 18 : quotient = in[33:18]; + default : quotient = in[15:0]; + endcase // case(shift) + + always @* + case(shift) + 0 : remainder = 16'b0; + 1 : remainder = {in[0],15'b0}; + 2 : remainder = {in[1:0],14'b0}; + 3 : remainder = {in[2:0],13'b0}; + 4 : remainder = {in[3:0],12'b0}; + 5 : remainder = {in[4:0],11'b0}; + 6 : remainder = {in[5:0],10'b0}; + 7 : remainder = {in[6:0],9'b0}; + 8 : remainder = {in[7:0],8'b0}; + 9 : remainder = {in[8:0],7'b0}; + 10 : remainder = {in[9:0],6'b0}; + 11 : remainder = {in[10:0],5'b0}; + 12 : remainder = {in[11:0],4'b0}; + 13 : remainder = {in[12:0],3'b0}; + 14 : remainder = {in[13:0],2'b0}; + 15 : remainder = {in[14:0],1'b0}; + 16 : remainder = in[15:0]; + 17 : remainder = in[16:1]; + 18 : remainder = in[17:2]; + default : remainder = 16'b0; + endcase // case(shift) + + always @* + case(shift) + 0 : msbs = in[33:15]; + 1 : msbs = {in[33],in[33:16]}; + 2 : msbs = {{2{in[33]}},in[33:17]}; + 3 : msbs = {{3{in[33]}},in[33:18]}; + 4 : msbs = {{4{in[33]}},in[33:19]}; + 5 : msbs = {{5{in[33]}},in[33:20]}; + 6 : msbs = {{6{in[33]}},in[33:21]}; + 7 : msbs = {{7{in[33]}},in[33:22]}; + 8 : msbs = {{8{in[33]}},in[33:23]}; + 9 : msbs = {{9{in[33]}},in[33:24]}; + 10 : msbs = {{10{in[33]}},in[33:25]}; + 11 : msbs = {{11{in[33]}},in[33:26]}; + 12 : msbs = {{12{in[33]}},in[33:27]}; + 13 : msbs = {{13{in[33]}},in[33:28]}; + 14 : msbs = {{14{in[33]}},in[33:29]}; + 15 : msbs = {{15{in[33]}},in[33:30]}; + 16 : msbs = {{16{in[33]}},in[33:31]}; + 17 : msbs = {{17{in[33]}},in[33:32]}; + 18 : msbs = {{18{in[33]}},in[33]}; + default : msbs = in[33:15]; + endcase // case(shift) + + assign in_range = &msbs | ~(|msbs); + assign out_unclipped = quotient + (in[33] & |remainder); + assign out = in_range ? out_unclipped : {in[33],{15{~in[33]}}}; + +endmodule // shifter |