97 lines
3.1 KiB
C
97 lines
3.1 KiB
C
/* *****************************************************************************
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* bcd/cas.c -- make a libg1m BCD out of an CAS BCD number.
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* Copyright (C) 2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
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*
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* This file is part of libg1m.
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* libg1m is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 3.0 of the License,
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* or (at your option) any later version.
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*
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* libg1m is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with libg1m; if not, see <http://www.gnu.org/licenses/>.
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* ************************************************************************** */
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#include <libg1m/internals.h>
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#define upr(N) ((bytes[(N)] & 0xf0) >> 4)
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#define lwr(N) (bytes[(N)] & 0xf)
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/**
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* g1m_bcd_fromcas:
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* Make a libg1m BCD out of an CAS BCD number.
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*
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* @arg raw the raw BCD.
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* @arg dest the not raw BCD.
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* @return the special bit, for simplicity.
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*/
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int g1m_bcd_fromcas(const cas_bcd_t *raw, g1m_bcd_t *bcd)
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{
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const unsigned char *bytes = raw->mantissa;
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/* get the exponent and sign */
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bcd->exp = (raw->exponent >> 4) * 10 + (raw->exponent & 0x0F);
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if (raw->signinfo & g1m_casbcd_pow_neg)
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bcd->exp = -bcd->exp;
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/* get the mantissa */
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bcd->mant[0] = lwr(0);
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bcd->mant[1] = upr(1);
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bcd->mant[2] = lwr(1);
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bcd->mant[3] = upr(2);
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bcd->mant[4] = lwr(2);
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bcd->mant[5] = upr(3);
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bcd->mant[6] = lwr(3);
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bcd->mant[7] = upr(4);
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bcd->mant[8] = lwr(4);
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bcd->mant[9] = upr(5);
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bcd->mant[10] = lwr(5);
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bcd->mant[11] = upr(6);
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bcd->mant[12] = lwr(6);
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bcd->mant[13] = upr(7);
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bcd->mant[14] = lwr(7);
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/* set the special things and return */
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bcd->flags = g1m_make_bcdflags(!!(raw->signinfo & g1m_casbcd_special),
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(raw->signinfo & g1m_casbcd_negative) == g1m_casbcd_negative, 15);
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return (g1m_bcd_has_special(bcd));
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}
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/**
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* g1m_bcd_tocas:
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* Make an CAS BCD number out of a libg1m BCD number.
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*
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* @arg bcd the not raw BCD.
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* @arg raw the raw BCD.
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*/
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void g1m_bcd_tocas(const g1m_bcd_t *bcd, cas_bcd_t *raw)
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{
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/* put the exponent */
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div_t d = div(abs(bcd->exp), 10);
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raw->exponent = (d.quot << 4) | d.rem;
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/* put the mantissa */
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raw->mantissa[0] = bcd->mant[0];
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raw->mantissa[1] = (bcd->mant[1] << 4) | bcd->mant[2];
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raw->mantissa[2] = (bcd->mant[3] << 4) | bcd->mant[4];
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raw->mantissa[3] = (bcd->mant[5] << 4) | bcd->mant[6];
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raw->mantissa[4] = (bcd->mant[7] << 4) | bcd->mant[8];
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raw->mantissa[5] = (bcd->mant[9] << 4) | bcd->mant[10];
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raw->mantissa[6] = (bcd->mant[11] << 4) | bcd->mant[12];
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raw->mantissa[7] = (bcd->mant[13] << 4) | bcd->mant[14];
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/* put the flags */
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raw->signinfo = 0;
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if (bcd->exp < 0)
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raw->signinfo |= g1m_casbcd_pow_neg;
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if (g1m_bcd_is_negative(bcd))
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raw->signinfo |= g1m_casbcd_negative;
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if (g1m_bcd_has_special(bcd))
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raw->signinfo |= g1m_casbcd_special;
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}
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