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daniel.kho |
/* Tauhop Digital Signal Processing package.
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Description
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This implements common functions used in digital signal processing.
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To Do:
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Author(s):
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- Daniel C.K. Kho, daniel.kho@opencores.org | daniel.kho@tauhop.com
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Copyright© 2014 Authors and Tauhop Solutions. All rights reserved.
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This source file may be used and distributed without
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restriction provided that this copyright statement is not
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removed from the file and that any derivative work contains
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the original copyright notice and the associated disclaimer.
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This source file is free software; you can redistribute it
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and/or modify it under the terms of the GNU Lesser General
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Public License as published by the Free Software Foundation;
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either version 2.1 of the License, or (at your option) any
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later version.
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This source is distributed in the hope that it will be
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useful, but WITHOUT ANY WARRANTY; without even the implied
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warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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PURPOSE. See the GNU Lesser General Public License for more
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details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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This notice and disclaimer must be retained as part of this text at all times.
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@dependencies:
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@created: Daniel C.K. Kho [daniel.kho@gmail.com] | [daniel.kho@tauhop.com]
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@info:
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Revision History: @see Mercurial log for full list of changes.
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*/
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/* TODO try using generic subprograms to have a single subprogram being
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passed generic types.
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*/
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library ieee; use ieee.std_logic_1164.all, ieee.numeric_std.all;
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package dsp_specific is
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function clamp(s:unsigned; low,high:unsigned) return unsigned;
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function clamp(s:unsigned; low,high:natural) return unsigned;
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function clamp(s:signed; low,high:signed) return signed;
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function clamp(s:signed; low,high:integer) return signed;
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function max(l,r:unsigned) return unsigned;
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function max(l,r:signed) return signed;
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function min(l,r:unsigned) return unsigned;
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function min(l,r:signed) return signed;
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end package dsp_specific;
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package body dsp_specific is
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function clamp(s:unsigned; low,high:unsigned) return unsigned is
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variable clamped:unsigned(s'range);
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begin
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clamped:=low when s<low else high when s>high else s;
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return clamped;
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end function clamp;
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function clamp(s:unsigned; low,high:natural) return unsigned is begin
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return clamp(s,to_unsigned(low,s'length),to_unsigned(high,s'length));
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end function clamp;
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function clamp(s:signed; low,high:signed) return signed is
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variable clamped:signed(s'range);
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begin
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clamped:=low when s<low else high when s>high else s;
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return clamped;
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end function clamp;
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function clamp(s:signed; low,high:integer) return signed is begin
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return clamp(s,to_signed(low,s'length),to_signed(high,s'length));
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end function clamp;
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function max(l,r:unsigned) return unsigned is begin
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/* FIXME support this in next standard. */
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--return r when r>l else l;
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if r>l then return r; end if;
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return l;
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end function max;
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function max(l,r:signed) return signed is begin
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--return r when r>l else l;
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if r>l then return r; end if;
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return l;
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end function max;
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function min(l,r:unsigned) return unsigned is begin
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--return r when r<l else l;
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if r<l then return r; end if;
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return l;
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end function min;
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function min(l,r:signed) return signed is begin
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--return r when r<l else l;
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if r<l then return r; end if;
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return l;
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end function min;
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end package body dsp_specific;
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library ieee; use ieee.std_logic_1164.all, ieee.numeric_std.all;
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package dsp_generic is generic(
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type T;
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--function "+"(l,r:T) return T is <>;
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--function "<"(l,r:T) return boolean is <>;
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--function ">"(l,r:T) return boolean is <>;
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--function ">"(l:T;r:natural) return boolean is <>;
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--function clamp(s,low,high:T) return T is <>;
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function clamp(s:T; low,high:natural) return T is <>
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);
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--function clamp generic(type T) parameter(s:T; low:T; high:T) return T;
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end package dsp_generic;
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package body dsp_generic is end package body dsp_generic;
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