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[/] [zipcpu/] [trunk/] [sim/] [cpp/] [twoc.cpp] - Blame information for rev 209

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1 209 dgisselq
////////////////////////////////////////////////////////////////////////////////
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//
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// Filename:    twoc.cpp
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//
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// Project:     Zip CPU -- a small, lightweight, RISC CPU soft core
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//
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// Purpose:     Some various two's complement related C++ helper routines.
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//              Specifically, these help extract signed numbers from
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//      packed bitfields, while guaranteeing that the upper bits are properly
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//      sign extended (or not) as desired.
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//
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// Creator:     Dan Gisselquist, Ph.D.
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//              Gisselquist Technology, LLC
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//
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////////////////////////////////////////////////////////////////////////////////
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//
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// Copyright (C) 2015,2017, Gisselquist Technology, LLC
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//
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// This program is free software (firmware): you can redistribute it and/or
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// modify it under the terms of  the GNU General Public License as published
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// by the Free Software Foundation, either version 3 of the License, or (at
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// your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
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// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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// for more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with this program.  (It's in the $(ROOT)/doc directory.  Run make with no
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// target there if the PDF file isn't present.)  If not, see
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// <http://www.gnu.org/licenses/> for a copy.
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//
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// License:     GPL, v3, as defined and found on www.gnu.org,
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//              http://www.gnu.org/licenses/gpl.html
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//
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//
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////////////////////////////////////////////////////////////////////////////////
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//
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//
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#include "twoc.h"
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long    sbits(const long val, const int bits) {
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        long    r;
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        r = val & ((1l<<bits)-1);
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        if (r & (1l << (bits-1)))
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                r |= (-1l << bits);
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        return r;
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}
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unsigned long   ubits(const long val, const int bits) {
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        unsigned long r = val & ((1l<<bits)-1);
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        return r;
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}
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