101 lines
3.5 KiB
C
101 lines
3.5 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 g1m_casbcd_t *raw, g1m_bcd_t *bcd)
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{
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const unsigned char *bytes = raw->g1m_casbcd_mant;
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/* get the exponent and sign */
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bcd->g1m_bcd_exp = (raw->g1m_casbcd_exp >> 4) * 10
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+ (raw->g1m_casbcd_exp & 0x0F);
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if (raw->g1m_casbcd_flags & g1m_casbcdflag_pow_neg)
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bcd->g1m_bcd_exp = -bcd->g1m_bcd_exp;
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/* get the mantissa */
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bcd->g1m_bcd_mant[0] = lwr(0);
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bcd->g1m_bcd_mant[1] = upr(1);
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bcd->g1m_bcd_mant[2] = lwr(1);
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bcd->g1m_bcd_mant[3] = upr(2);
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bcd->g1m_bcd_mant[4] = lwr(2);
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bcd->g1m_bcd_mant[5] = upr(3);
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bcd->g1m_bcd_mant[6] = lwr(3);
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bcd->g1m_bcd_mant[7] = upr(4);
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bcd->g1m_bcd_mant[8] = lwr(4);
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bcd->g1m_bcd_mant[9] = upr(5);
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bcd->g1m_bcd_mant[10] = lwr(5);
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bcd->g1m_bcd_mant[11] = upr(6);
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bcd->g1m_bcd_mant[12] = lwr(6);
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bcd->g1m_bcd_mant[13] = upr(7);
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bcd->g1m_bcd_mant[14] = lwr(7);
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/* set the special things and return */
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bcd->g1m_bcd_flags = g1m_make_bcdflags(
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!!(raw->g1m_casbcd_flags & g1m_casbcdflag_special),
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(raw->g1m_casbcd_flags & g1m_casbcdflag_negative)
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== g1m_casbcdflag_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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# define g1m_bcd_m g1m_bcd_mant
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void g1m_bcd_tocas(const g1m_bcd_t *bcd, g1m_casbcd_t *raw)
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{
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/* put the exponent */
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div_t d = div(abs(bcd->g1m_bcd_exp), 10);
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raw->g1m_casbcd_exp = (d.quot << 4) | d.rem;
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/* put the mantissa */
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raw->g1m_casbcd_mant[0] = bcd->g1m_bcd_m[0];
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raw->g1m_casbcd_mant[1] = (bcd->g1m_bcd_m[1] << 4) | bcd->g1m_bcd_m[2];
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raw->g1m_casbcd_mant[2] = (bcd->g1m_bcd_m[3] << 4) | bcd->g1m_bcd_m[4];
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raw->g1m_casbcd_mant[3] = (bcd->g1m_bcd_m[5] << 4) | bcd->g1m_bcd_m[6];
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raw->g1m_casbcd_mant[4] = (bcd->g1m_bcd_m[7] << 4) | bcd->g1m_bcd_m[8];
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raw->g1m_casbcd_mant[5] = (bcd->g1m_bcd_m[9] << 4) | bcd->g1m_bcd_m[10];
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raw->g1m_casbcd_mant[6] = (bcd->g1m_bcd_m[11] << 4) | bcd->g1m_bcd_m[12];
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raw->g1m_casbcd_mant[7] = (bcd->g1m_bcd_m[13] << 4) | bcd->g1m_bcd_m[14];
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/* put the flags */
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raw->g1m_casbcd_flags = 0;
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if (bcd->g1m_bcd_exp < 0)
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raw->g1m_casbcd_flags |= g1m_casbcdflag_pow_neg;
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if (g1m_bcd_is_negative(bcd))
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raw->g1m_casbcd_flags |= g1m_casbcdflag_negative;
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if (g1m_bcd_has_special(bcd))
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raw->g1m_casbcd_flags |= g1m_casbcdflag_special;
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}
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