<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"> <title>double2scs.c Source File</title> <link href="doxygen.css" rel="stylesheet" type="text/css"> </head><body> <!-- Generated by Doxygen 1.2.15 --> <center> <a class="qindex" href="index.html">Main Page</a> <a class="qindex" href="annotated.html">Data Structures</a> <a class="qindex" href="files.html">File List</a> <a class="qindex" href="functions.html">Data Fields</a> <a class="qindex" href="globals.html">Globals</a> </center> <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 </pre></div><hr><address align="right"><small>Generated on Tue Jun 17 10:15:51 2003 for SCSLib by <a href="http://www.doxygen.org/index.html"> <img src="doxygen.png" alt="doxygen" align="middle" border=0 width=110 height=53></a>1.2.15 </small></address> </body> </html>