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<hr><h1>double2scs.c</h1><a href="double2scs_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre>00001 <font class="comment">/** Conversion of floating-point double to SCS</font>
00002 <font class="comment">@file double2scs.c</font>
00003 <font class="comment"></font>
00004 <font class="comment">@author Defour David David.Defour@ens-lyon.fr</font>
00005 <font class="comment">@author Florent de Dinechin Florent.de.Dinechin@ens-lyon.fr </font>
00006 <font class="comment"></font>
00007 <font class="comment">This file is part of the SCS library.</font>
00008 <font class="comment">*/</font>
00009
00010 <font class="comment">/*</font>
00011 <font class="comment">Copyright (C) 2002 David Defour and Florent de Dinechin</font>
00012 <font class="comment"></font>
00013 <font class="comment"> This library is free software; you can redistribute it and/or</font>
00014 <font class="comment"> modify it under the terms of the GNU Lesser General Public</font>
00015 <font class="comment"> License as published by the Free Software Foundation; either</font>
00016 <font class="comment"> version 2.1 of the License, or (at your option) any later version.</font>
00017 <font class="comment"></font>
00018 <font class="comment"> This library is distributed in the hope that it will be useful,</font>
00019 <font class="comment"> but WITHOUT ANY WARRANTY; without even the implied warranty of</font>
00020 <font class="comment"> MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</font>
00021 <font class="comment"> Lesser General Public License for more details.</font>
00022 <font class="comment"></font>
00023 <font class="comment"> You should have received a copy of the GNU Lesser General Public</font>
00024 <font class="comment"> License along with this library; if not, write to the Free Software</font>
00025 <font class="comment"> Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA</font>
00026 <font class="comment"></font>
00027 <font class="comment"> */</font>
00028 <font class="preprocessor">#include "<a class="code" href="scs_8h.html">scs.h</a>"</font>
00029 <font class="preprocessor">#include "<a class="code" href="scs__private_8h.html">scs_private.h</a>"</font>
00030
00031 <font class="comment"></font>
00032 <font class="comment">/** Convert a double precision number in it SCS multiprecision</font>
00033 <font class="comment"> representation</font>
00034 <font class="comment"> */</font>
00035
<a name="l00036"></a><a class="code" href="double2scs_8c.html#a0">00036</a> <font class="keywordtype">void</font> <a class="code" href="double2scs_8c.html#a0">scs_set_d</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <font class="keywordtype">double</font> x){
00037 scs_db_number nb, mantissa;
00038 <font class="keywordtype">int</font> exponent, exponent_remainder;
00039 <font class="keywordtype">int</font> ind, i;
00040
00041 <font class="keywordflow">if</font>(x>=0){R_SGN = 1; nb.d = x;}
00042 <font class="keywordflow">else</font> {R_SGN = -1; nb.d = -x;}
00043
00044 exponent = nb.i[HI_ENDIAN] & 0x7ff00000 ;
00045
00046 <font class="keywordflow">if</font> (exponent == 0x7ff00000) {
00047 <font class="comment">/*</font>
00048 <font class="comment"> * x = +/- Inf, s/qNAN</font>
00049 <font class="comment"> */</font>
00050 R_EXP = x;
00051 <font class="keywordflow">for</font>(i=0; i<SCS_NB_WORDS; i++)
00052 R_HW[i] = 0;
00053
00054 R_IND = 0;
00055 R_SGN = 1;
00056 }
00057
00058 <font class="keywordflow">else</font> { <font class="comment">/* Normals, denormals, +/- 0. */</font>
00059
00060 <font class="comment">/* This number is not an exception */</font>
00061 R_EXP = 1;
00062
00063 <font class="preprocessor">#if 1</font>
00064 <font class="preprocessor"></font>
00065 <font class="keywordflow">if</font> (exponent == 0){
00066 <font class="comment">/* x is a denormal number : bring it back to the normal range */</font>
00067 nb.d = nb.d * SCS_RADIX_TWO_DOUBLE; <font class="comment">/* 2^(2.SCS_NB_BITS) */</font>
00068 exponent = nb.i[HI_ENDIAN] & 0x7ff00000 ;
00069 R_IND = -2;
00070 }<font class="keywordflow">else</font> {
00071 R_IND = 0;
00072 }
00073
00074 exponent = exponent >> 20; <font class="comment">/* get the actual value */</font>
00075
00076 ind = ((exponent +((100*SCS_NB_BITS)-1023))/SCS_NB_BITS) - 100 ;
00077 <font class="comment">/* means : = (exponent -1023 + 100*SCS_NB_BITS)/SCS_NB_BITS -100 </font>
00078 <font class="comment"> The business with 100*SCS_NB_BITS is to stay within the positive</font>
00079 <font class="comment"> range for exponent_remainder between 1 and SCS_NB_BITS */</font>
00080
00081 exponent_remainder = exponent - 1022 - (SCS_NB_BITS*ind);
00082
00083 R_IND += ind;
00084
00085 <font class="comment">/* now get the mantissa and add the implicit 1 in fp. format*/</font>
00086 mantissa.l = (nb.l & 0x000fffffffffffff) | 0x0010000000000000;
00087
00088
00089 <font class="comment">/* and spread it over the structure</font>
00090 <font class="comment"> Everything here is 64-bit arithmetic */</font>
00091 R_HW[0] = mantissa.l >> (53 - exponent_remainder);
00092
00093 <font class="comment">/* 11 = 64-53 */</font>
00094 mantissa.l = (mantissa.l << (exponent_remainder+11));
00095 R_HW[1] = (mantissa.i[HI_ENDIAN] >> (32 - SCS_NB_BITS))& SCS_MASK_RADIX ;
00096 mantissa.l = (mantissa.l << SCS_NB_BITS);
00097 R_HW[2] = (mantissa.i[HI_ENDIAN] >> (32 - SCS_NB_BITS))& SCS_MASK_RADIX ;
00098 <font class="preprocessor">#if SCS_NB_BITS < 27</font>
00099 <font class="preprocessor"></font> mantissa.l = (mantissa.l << SCS_NB_BITS);
00100 R_HW[3] = (mantissa.i[HI_ENDIAN] >> (32 - SCS_NB_BITS))& SCS_MASK_RADIX ;
00101 <font class="preprocessor">#else</font>
00102 <font class="preprocessor"></font> R_HW[3] = 0 ;
00103 <font class="preprocessor">#endif</font>
00104 <font class="preprocessor"></font>
00105 <font class="preprocessor">#if (SCS_NB_WORDS==8)</font>
00106 <font class="preprocessor"></font> R_HW[4] = 0; R_HW[5] = 0; R_HW[6] = 0; R_HW[7] = 0;
00107 <font class="preprocessor">#else</font>
00108 <font class="preprocessor"></font> <font class="keywordflow">for</font>(i=4; i<SCS_NB_WORDS; i++)
00109 R_HW[i] = 0;
00110 <font class="preprocessor">#endif</font>
00111 <font class="preprocessor"></font>
00112
00113
00114 <font class="preprocessor">#else </font><font class="comment">/* Other algorithm as in the research report. Slower */</font>
00115 R_IND = 0;
00116
00117 <font class="keywordflow">while</font>(nb.d>SCS_RADIX_ONE_DOUBLE) {
00118 R_IND++;
00119 nb.d *= SCS_RADIX_MONE_DOUBLE;
00120 }
00121
00122 <font class="keywordflow">while</font>(nb.d<1) {
00123 R_IND--;
00124 nb.d *= SCS_RADIX_ONE_DOUBLE;
00125 }
00126
00127 i=0;
00128 <font class="keywordflow">while</font>(nb.d != 0){
00129 R_HW[i] = (<font class="keywordtype">unsigned</font> <font class="keywordtype">int</font>) nb.d;
00130 nb.d = (nb.d - (double)R_HW[i]) * SCS_RADIX_ONE_DOUBLE;
00131 i++;
00132 }
00133 <font class="keywordflow">for</font>(; i<SCS_NB_WORDS; i++)
00134 R_HW[i] = 0;
00135
00136 <font class="preprocessor">#endif</font>
00137 <font class="preprocessor"></font>
00138 } <font class="comment">/* end if test NaN etc */</font>
00139
00140 <font class="keywordflow">return</font>;
00141 }
00142
00143 <font class="comment"></font>
00144 <font class="comment">/**</font>
00145 <font class="comment"> Convert an integer number in it scs multiprecision</font>
00146 <font class="comment"> representation</font>
00147 <font class="comment"> */</font>
<a name="l00148"></a><a class="code" href="double2scs_8c.html#a1">00148</a> <font class="keywordtype">void</font> <a class="code" href="double2scs_8c.html#a1">scs_set_si</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <font class="keywordtype">signed</font> <font class="keywordtype">int</font> x){
00149 <font class="keywordtype">unsigned</font> <font class="keywordtype">int</font> ux;
00150 <font class="keywordtype">int</font> i;
00151
00152 <font class="keywordflow">if</font>(x>=0){R_SGN = 1; ux = x;}
00153 <font class="keywordflow">else</font> {R_SGN = -1; ux = -x;}
00154
00155
00156 <font class="keywordflow">if</font> (ux > SCS_RADIX){
00157 R_IND = 1;
00158 R_HW[0] = (ux - SCS_RADIX) >> SCS_NB_BITS;
00159 R_HW[1] = ux - (R_HW[0] << SCS_NB_BITS);
00160 }<font class="keywordflow">else</font> {
00161 R_IND = 0;
00162 R_HW[0] = ux;
00163 R_HW[1] = 0;
00164 }
00165
00166 <font class="keywordflow">for</font>(i=2; i<SCS_NB_WORDS; i++)
00167 R_HW[i] = 0;
00168
00169 <font class="keywordflow">if</font> (x != 0) R_EXP = 1;
00170 <font class="keywordflow">else</font> R_EXP = 0;
00171
00172 <font class="keywordflow">return</font>;
00173 }
00174
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