100 lines
3.4 KiB
C
100 lines
3.4 KiB
C
/* *****************************************************************************
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* bcd/mcs.c -- make a libg1m BCD out of an MCS 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)] >> 4)
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#define lwr(N) (bytes[(N)] & 15)
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/**
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* g1m_bcd_frommcs:
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* Make a libg1m BCD out of an MCS 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_frommcs(const g1m_mcsbcd_t *raw, g1m_bcd_t *bcd)
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{
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const unsigned char *bytes = raw->g1m_mcsbcd_BCDval;
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/* get the exponent and correct it */
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int exp = (upr(0) & 7) * 100 + lwr(0) * 10 + upr(1), neg = 0;
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if (exp >= 500) exp -= 500, neg = 1;
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bcd->g1m_bcd_exp = (char)(exp - 99);
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/* set the flags */
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bcd->g1m_bcd_flags = g1m_make_bcdflags((bytes[0] & 0x80) >> 7, neg, 15);
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/* get the mantissa */
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bcd->g1m_bcd_mant[0] = lwr(1);
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bcd->g1m_bcd_mant[1] = upr(2);
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bcd->g1m_bcd_mant[2] = lwr(2);
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bcd->g1m_bcd_mant[3] = upr(3);
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bcd->g1m_bcd_mant[4] = lwr(3);
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bcd->g1m_bcd_mant[5] = upr(4);
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bcd->g1m_bcd_mant[6] = lwr(4);
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bcd->g1m_bcd_mant[7] = upr(5);
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bcd->g1m_bcd_mant[8] = lwr(5);
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bcd->g1m_bcd_mant[9] = upr(6);
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bcd->g1m_bcd_mant[10] = lwr(6);
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bcd->g1m_bcd_mant[11] = upr(7);
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bcd->g1m_bcd_mant[12] = lwr(7);
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bcd->g1m_bcd_mant[13] = upr(8);
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bcd->g1m_bcd_mant[14] = lwr(8);
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/* return the special bit */
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return (g1m_bcd_has_special(bcd));
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}
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/**
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* g1m_bcd_tomcs:
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* Make an MCS 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_tomcs(const g1m_bcd_t *bcd, g1m_mcsbcd_t *raw)
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{
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int exp = bcd->g1m_bcd_exp + 99;
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if (g1m_bcd_is_negative(bcd)) exp += 500;
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/* put the exponent (and first digit of the mantissa) */
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div_t c = div(exp, 100);
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div_t d = div(c.rem, 10);
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raw->g1m_mcsbcd_BCDval[0] = (c.quot << 4) | d.quot
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| (!!g1m_bcd_has_special(bcd) << 7);
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raw->g1m_mcsbcd_BCDval[1] = (d.rem << 4) | bcd->g1m_bcd_mant[0];
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/* put the mantissa */
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raw->g1m_mcsbcd_BCDval[2] = (bcd->g1m_bcd_m[1] << 4) | bcd->g1m_bcd_m[2];
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raw->g1m_mcsbcd_BCDval[3] = (bcd->g1m_bcd_m[3] << 4) | bcd->g1m_bcd_m[4];
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raw->g1m_mcsbcd_BCDval[4] = (bcd->g1m_bcd_m[5] << 4) | bcd->g1m_bcd_m[6];
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raw->g1m_mcsbcd_BCDval[5] = (bcd->g1m_bcd_m[7] << 4) | bcd->g1m_bcd_m[8];
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raw->g1m_mcsbcd_BCDval[6] = (bcd->g1m_bcd_m[9] << 4) | bcd->g1m_bcd_m[10];
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raw->g1m_mcsbcd_BCDval[7] = (bcd->g1m_bcd_m[11] << 4) | bcd->g1m_bcd_m[12];
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raw->g1m_mcsbcd_BCDval[8] = (bcd->g1m_bcd_m[13] << 4) | bcd->g1m_bcd_m[14];
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/* set the align zone */
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raw->g1m_mcsbcd__align[0] = 0;
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raw->g1m_mcsbcd__align[1] = 0;
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raw->g1m_mcsbcd__align[2] = 0;
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}
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