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<hr><h1>multiplication_scs.c</h1><a href="multiplication__scs_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre>00001 <font class="comment">/** Functions for SCS multiplication operations </font>
00002 <font class="comment">@file multiplication_scs.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
00029 <font class="preprocessor">#include "<a class="code" href="scs_8h.html">scs.h</a>"</font>
00030 <font class="preprocessor">#include "<a class="code" href="scs__private_8h.html">scs_private.h</a>"</font>
00031
00032 <font class="preprocessor">#if 0 </font><font class="comment">/* used to help debugging */</font>
00033 <font class="keywordtype">void</font> pr(<font class="keywordtype">char</font>* s,<font class="keywordtype">double</font> d) {
00034 scs_db_number x;
00035 x.d=d;
00036 printf(s);printf(<font class="stringliteral">" "</font>);
00037 printf(<font class="stringliteral">"%8x%8x . 2^%d (%8f %8x %8x) \n"</font>,
00038 (x.i[HI_ENDIAN]&0x000FFFFF)+0x00100000,
00039 x.i[LO_ENDIAN],
00040 (x.i[HI_ENDIAN]>>20)-1023,
00041 x.d,
00042 x.i[HI_ENDIAN],
00043 x.i[LO_ENDIAN]);
00044 }
00045 <font class="preprocessor">#endif</font>
00046 <font class="preprocessor"></font>
00047
00048 <font class="comment">/***************************************************************/</font>
00049 <font class="comment">/* First a few #defines selecting between architectures where integer</font>
00050 <font class="comment"> multiplication is faster than FP multiplication (the normal case)</font>
00051 <font class="comment"> and those where it is the opposite (some Sparcs). The latter</font>
00052 <font class="comment"> doesn't work but might at some point, so the code remains */</font>
00053
00054 <font class="preprocessor">#ifdef SCS_USE_FLT_MULT</font>
00055 <font class="preprocessor"></font><font class="comment">/* Compute the carry of r1, remove it from r1, and add it to r0. This</font>
00056 <font class="comment"> doesn't work: how to get a value truncated using only</font>
00057 <font class="comment"> round-to-nearest FP ? Besides it doesn't work on x86 for at least two</font>
00058 <font class="comment"> reasons : extended precision FP arithmetic, and a #define below. */</font>
00059 <font class="preprocessor">#define SCS_CARRY_PROPAGATE(r1,r0,tmp) \</font>
00060 <font class="preprocessor"> {tmp=((r1-SCS_FLT_TRUNC_CST)+SCS_FLT_SHIFT_CST)-SCS_FLT_SHIFT_CST; r1-= tmp; r0+=tmp*SCS_RADIX_MONE_DOUBLE;} </font>
00061 <font class="preprocessor"></font>
00062 <font class="keyword">typedef</font> <font class="keywordtype">double</font> SCS_CONVERSION_MUL;
00063
00064 <font class="preprocessor">#else </font><font class="comment">/* SCS_USE_FLT_MULT*/</font>
00065
00066 <font class="comment">/* Compute the carry of r1, remove it from r1, and add it to r0 */</font>
00067 <font class="preprocessor">#define SCS_CARRY_PROPAGATE(r1,r0,tmp) \</font>
00068 <font class="preprocessor"> {tmp = r1>>SCS_NB_BITS; r0 += tmp; r1 -= (tmp<<SCS_NB_BITS);} </font>
00069 <font class="preprocessor"></font><font class="keyword">typedef</font> <font class="keywordtype">unsigned</font> <font class="keywordtype">long</font> <font class="keywordtype">long</font> <font class="keywordtype">int</font> SCS_CONVERSION_MUL;
00070 <font class="preprocessor">#endif </font><font class="comment">/* SCS_USE_FLT_MULT */</font>
00071
00072
00073
00074
00075
00076
00077
00078 <font class="comment">/************************************************************/</font>
00079 <font class="comment">/* We have unrolled the loops for SCS_NB_WORDS==4 or 8 </font>
00080 <font class="comment"></font>
00081 <font class="comment"> We just wish gcc would do it for us ! There are option switches,</font>
00082 <font class="comment"> but they don't lead to any performance improvement. When they do,</font>
00083 <font class="comment"> this part of the source code will be removed.</font>
00084 <font class="comment"></font>
00085 <font class="comment"> In the meantime, feel free to unroll for other values. */</font>
00086
00087
00088 <font class="comment">/***************************/</font>
00089 <font class="preprocessor">#if (SCS_NB_WORDS==4)</font>
00090 <font class="preprocessor"></font><font class="comment">/***************************/</font>
00091 <font class="keywordtype">void</font> <a class="code" href="multiplication__scs_8c.html#a2">scs_mul</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <a class="code" href="structscs.html">scs_ptr</a> x, <a class="code" href="structscs.html">scs_ptr</a> y){
00092 SCS_CONVERSION_MUL val, tmp;
00093 SCS_CONVERSION_MUL r0,r1,r2,r3,r4;
00094 SCS_CONVERSION_MUL x0,x1,x2,x3;
00095 <font class="keywordtype">int</font> y0,y1,y2,y3;
00096
00097 R_EXP = X_EXP * Y_EXP;
00098 R_SGN = X_SGN * Y_SGN;
00099 R_IND = X_IND + Y_IND;
00100
00101 <font class="comment">/* Partial products computation */</font>
00102 x3=X_HW[3]; y3=Y_HW[3]; x2=X_HW[2]; y2=Y_HW[2];
00103 x1=X_HW[1]; y1=Y_HW[1]; x0=X_HW[0]; y0=Y_HW[0];
00104
00105 r4 = x3*y1 + x2*y2 + x1*y3;
00106 r3 = x3*y0 + x2*y1 + x1*y2 + x0*y3;
00107 r2 = x2*y0 + x1*y1 + x0*y2;
00108 r1 = x1*y0 + x0*y1 ;
00109 r0 = x0*y0;
00110
00111 val= 0;
00112 <font class="comment">/* Carry Propagate */</font>
00113 SCS_CARRY_PROPAGATE(r4,r3,tmp)
00114 SCS_CARRY_PROPAGATE(r3,r2,tmp)
00115 SCS_CARRY_PROPAGATE(r2,r1,tmp)
00116 SCS_CARRY_PROPAGATE(r1,r0,tmp)
00117 SCS_CARRY_PROPAGATE(r0,val,tmp)
00118
00119 <font class="keywordflow">if</font>(val != 0){
00120 <font class="comment">/* shift all the digits ! */</font>
00121 R_HW[0] = val; R_HW[1] = r0; R_HW[2] = r1; R_HW[3] = r2;
00122 R_IND += 1;
00123 }
00124 <font class="keywordflow">else</font> {
00125 R_HW[0] = r0; R_HW[1] = r1; R_HW[2] = r2; R_HW[3] = r3;
00126 }
00127
00128 }
00129
00130
00131 <font class="keywordtype">void</font> <a class="code" href="multiplication__scs_8c.html#a3">scs_square</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <a class="code" href="structscs.html">scs_ptr</a> x){
00132 SCS_CONVERSION_MUL r0,r1,r2,r3,r4;
00133 SCS_CONVERSION_MUL x0,x1,x2,x3;
00134 SCS_CONVERSION_MUL val, tmp;
00135
00136
00137 R_EXP = X_EXP * X_EXP;
00138 R_IND = X_IND + X_IND;
00139 R_SGN = 1;
00140
00141 <font class="comment">/*</font>
00142 <font class="comment"> * Calcul des PP</font>
00143 <font class="comment"> */</font>
00144 x3=X_HW[3]; x2=X_HW[2]; x1=X_HW[1]; x0=X_HW[0];
00145
00146 r0 = x0*x0;
00147 r1 = (x0*x1)* 2 ;
00148 r2 = x1*x1 + (x0*x2*2);
00149 r3 = (x1*x2 + x0*x3)* 2;
00150 r4 = x2*x2 + (x1*x3)* 2;
00151
00152 val= 0;
00153 <font class="comment">/* Propagation des retenues */</font>
00154 SCS_CARRY_PROPAGATE(r4,r3,tmp)
00155 SCS_CARRY_PROPAGATE(r3,r2,tmp)
00156 SCS_CARRY_PROPAGATE(r2,r1,tmp)
00157 SCS_CARRY_PROPAGATE(r1,r0,tmp)
00158 SCS_CARRY_PROPAGATE(r0,val,tmp)
00159
00160 <font class="keywordflow">if</font>(val != 0){
00161 <font class="comment">/* shift all the digits ! */</font>
00162 R_HW[0] = val; R_HW[1] = r0; R_HW[2] = r1; R_HW[3] = r2;
00163 R_IND += 1;
00164 }
00165 <font class="keywordflow">else</font> {
00166 R_HW[0] = r0; R_HW[1] = r1; R_HW[2] = r2; R_HW[3] = r3;
00167 }
00168
00169 }
00170
00171
00172
00173
00174
00175
00176
00177 <font class="comment">/***************************/</font>
00178 <font class="preprocessor">#elif (SCS_NB_WORDS==8)</font>
00179 <font class="preprocessor"></font><font class="comment">/***************************/</font>
00180 <font class="keywordtype">void</font> <a class="code" href="multiplication__scs_8c.html#a2">scs_mul</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <a class="code" href="structscs.html">scs_ptr</a> x, <a class="code" href="structscs.html">scs_ptr</a> y){
00181 SCS_CONVERSION_MUL val, tmp;
00182 SCS_CONVERSION_MUL r0,r1,r2,r3,r4,r5,r6,r7,r8;
00183 SCS_CONVERSION_MUL x0,x1,x2,x3,x4,x5,x6,x7;
00184 <font class="keywordtype">int</font> y0,y1,y2,y3,y4,y5,y6,y7;
00185
00186 R_EXP = X_EXP * Y_EXP;
00187 R_SGN = X_SGN * Y_SGN;
00188 R_IND = X_IND + Y_IND;
00189
00190 <font class="comment">/* Partial products computation */</font>
00191 x7=X_HW[7]; y7=Y_HW[7]; x6=X_HW[6]; y6=Y_HW[6];
00192 x5=X_HW[5]; y5=Y_HW[5]; x4=X_HW[4]; y4=Y_HW[4];
00193 x3=X_HW[3]; y3=Y_HW[3]; x2=X_HW[2]; y2=Y_HW[2];
00194 x1=X_HW[1]; y1=Y_HW[1]; x0=X_HW[0]; y0=Y_HW[0];
00195
00196 r8 = x7*y1 + x6*y2 + x5*y3 + x4*y4 + x3*y5 + x2*y6 + x1*y7;
00197 r7 = x7*y0 + x6*y1 + x5*y2 + x4*y3 + x3*y4 + x2*y5 + x1*y6 + x0*y7;
00198 r6 = x6*y0 + x5*y1 + x4*y2 + x3*y3 + x2*y4 + x1*y5 + x0*y6;
00199 r5 = x5*y0 + x4*y1 + x3*y2 + x2*y3 + x1*y4 + x0*y5;
00200 r4 = x4*y0 + x3*y1 + x2*y2 + x1*y3 + x0*y4 ;
00201 r3 = x3*y0 + x2*y1 + x1*y2 + x0*y3;
00202 r2 = x2*y0 + x1*y1 + x0*y2;
00203 r1 = x1*y0 + x0*y1 ;
00204 r0 = x0*y0 ;
00205
00206 val= 0;
00207 <font class="comment">/* Carry Propagate */</font>
00208 SCS_CARRY_PROPAGATE(r8,r7,tmp)
00209 SCS_CARRY_PROPAGATE(r7,r6,tmp)
00210 SCS_CARRY_PROPAGATE(r6,r5,tmp)
00211 SCS_CARRY_PROPAGATE(r5,r4,tmp)
00212 SCS_CARRY_PROPAGATE(r4,r3,tmp)
00213 SCS_CARRY_PROPAGATE(r3,r2,tmp)
00214 SCS_CARRY_PROPAGATE(r2,r1,tmp)
00215 SCS_CARRY_PROPAGATE(r1,r0,tmp)
00216 SCS_CARRY_PROPAGATE(r0,val,tmp)
00217
00218 <font class="keywordflow">if</font>(val != 0){
00219 <font class="comment">/* shift all the digits ! */</font>
00220 R_HW[0] = val; R_HW[1] = r0; R_HW[2] = r1; R_HW[3] = r2;
00221 R_HW[4] = r3; R_HW[5] = r4; R_HW[6] = r5; R_HW[7] = r6;
00222 R_IND += 1;
00223 }
00224 <font class="keywordflow">else</font> {
00225 R_HW[0] = r0; R_HW[1] = r1; R_HW[2] = r2; R_HW[3] = r3;
00226 R_HW[4] = r4; R_HW[5] = r5; R_HW[6] = r6; R_HW[7] = r7;
00227 }
00228
00229 }
00230
00231
00232 <font class="keywordtype">void</font> <a class="code" href="multiplication__scs_8c.html#a3">scs_square</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <a class="code" href="structscs.html">scs_ptr</a> x){
00233 SCS_CONVERSION_MUL r0,r1,r2,r3,r4,r5,r6,r7,r8;
00234 SCS_CONVERSION_MUL x0,x1,x2,x3,x4,x5,x6,x7;
00235 SCS_CONVERSION_MUL val, tmp;
00236
00237
00238 R_EXP = X_EXP * X_EXP;
00239 R_IND = X_IND + X_IND;
00240 R_SGN = 1;
00241
00242 <font class="comment">/*</font>
00243 <font class="comment"> * Partial products</font>
00244 <font class="comment"> */</font>
00245 x7=X_HW[7]; x6=X_HW[6]; x5=X_HW[5]; x4=X_HW[4];
00246 x3=X_HW[3]; x2=X_HW[2]; x1=X_HW[1]; x0=X_HW[0];
00247
00248 r0 = x0*x0;
00249 r1 = (x0*x1)* 2 ;
00250 r2 = x1*x1 + (x0*x2*2);
00251 r3 = (x1*x2 + x0*x3)* 2;
00252 r4 = x2*x2 + (x1*x3 + x0*x4)* 2;
00253 r5 = (x2*x3 + x1*x4 + x0*x5)* 2;
00254 r6 = x3*x3 + (x2*x4 + x1*x5 + x0*x6)* 2;
00255 r7 = (x3*x4 + x2*x5 + x1*x6 + x0*x7)* 2;
00256 r8 = x4*x4 + (x3*x5 + x2*x6 + x1*x7)* 2;
00257
00258 val= 0;
00259 <font class="comment">/* Carry propagation */</font>
00260 SCS_CARRY_PROPAGATE(r8,r7,tmp)
00261 SCS_CARRY_PROPAGATE(r7,r6,tmp)
00262 SCS_CARRY_PROPAGATE(r6,r5,tmp)
00263 SCS_CARRY_PROPAGATE(r5,r4,tmp)
00264 SCS_CARRY_PROPAGATE(r4,r3,tmp)
00265 SCS_CARRY_PROPAGATE(r3,r2,tmp)
00266 SCS_CARRY_PROPAGATE(r2,r1,tmp)
00267 SCS_CARRY_PROPAGATE(r1,r0,tmp)
00268 SCS_CARRY_PROPAGATE(r0,val,tmp)
00269
00270 <font class="keywordflow">if</font>(val != 0){
00271 <font class="comment">/* shift all the digits ! */</font>
00272 R_HW[0] = val; R_HW[1] = r0; R_HW[2] = r1; R_HW[3] = r2;
00273 R_HW[4] = r3; R_HW[5] = r4; R_HW[6] = r5; R_HW[7] = r6;
00274 R_IND += 1;
00275 }
00276 <font class="keywordflow">else</font> {
00277 R_HW[0] = r0; R_HW[1] = r1; R_HW[2] = r2; R_HW[3] = r3;
00278 R_HW[4] = r4; R_HW[5] = r5; R_HW[6] = r6; R_HW[7] = r7;
00279 }
00280
00281 }
00282
00283
00284
00285 <font class="comment">/***************************/</font>
00286 <font class="preprocessor">#else</font>
00287 <font class="preprocessor"></font><font class="comment">/***************************/</font>
00288 <font class="comment">/* From there on, the normal, unrolled case */</font>
00289
00290
<a name="l00291"></a><a class="code" href="multiplication__scs_8c.html#a2">00291</a> <font class="keywordtype">void</font> <a class="code" href="multiplication__scs_8c.html#a2">scs_mul</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <a class="code" href="structscs.html">scs_ptr</a> x, <a class="code" href="structscs.html">scs_ptr</a> y){
00292 SCS_CONVERSION_MUL RES[SCS_NB_WORDS+1];
00293 SCS_CONVERSION_MUL val, tmp;
00294 <font class="keywordtype">int</font> i, j;
00295
00296 R_EXP = X_EXP * Y_EXP;
00297 R_SGN = X_SGN * Y_SGN;
00298 R_IND = X_IND + Y_IND;
00299
00300 <font class="keywordflow">for</font>(i=0; i<=SCS_NB_WORDS; i++)
00301 RES[i]=0;
00302
00303 <font class="comment">/* Compute only the first half of the partial product. See the</font>
00304 <font class="comment"> unrolled code for an example of what we compute */</font>
00305
00306 <font class="preprocessor">#ifdef SCS_TYPECPU_X86</font>
00307 <font class="preprocessor"></font> <font class="comment">/* This is the only place where there is assembly code to force 64-bit</font>
00308 <font class="comment"> arithmetic. Someday gcc will catch up here, too.</font>
00309 <font class="comment"> */</font>
00310 {
00311 scs_db_number t;
00312 <font class="comment">/* i=0 */</font>
00313 <font class="keywordflow">for</font>(j=0; j<(SCS_NB_WORDS); j++) {
00314 __asm__ <font class="keyword">volatile</font>(<font class="stringliteral">"mull %3"</font>
00315 : <font class="stringliteral">"=a"</font> (t.i[LO_ENDIAN]), <font class="stringliteral">"=d"</font> (t.i[HI_ENDIAN])
00316 : <font class="stringliteral">"a"</font> (X_HW[0]) , <font class="stringliteral">"g"</font> (Y_HW[j]));
00317 RES[j] += t.l;
00318 }
00319 <font class="comment">/* i = 1..SCS_NB_WORDS-1 */</font>
00320 <font class="keywordflow">for</font>(i=1 ; i<SCS_NB_WORDS; i++){
00321 <font class="keywordflow">for</font>(j=0; j<(SCS_NB_WORDS-i); j++){
00322 __asm__ <font class="keyword">volatile</font>(<font class="stringliteral">"mull %3"</font>
00323 : <font class="stringliteral">"=a"</font> (t.i[LO_ENDIAN]), <font class="stringliteral">"=d"</font> (t.i[HI_ENDIAN])
00324 : <font class="stringliteral">"a"</font> (X_HW[i]) , <font class="stringliteral">"g"</font> (Y_HW[j]));
00325 RES[i+j] += t.l;
00326 }
00327 __asm__ <font class="keyword">volatile</font>(<font class="stringliteral">"mull %3"</font>
00328 : <font class="stringliteral">"=a"</font> (t.i[LO_ENDIAN]), <font class="stringliteral">"=d"</font> (t.i[HI_ENDIAN])
00329 : <font class="stringliteral">"a"</font> (X_HW[i]) , <font class="stringliteral">"g"</font> (Y_HW[j]));
00330 <font class="comment">/* here j==SCS_NB_WORDS-i */</font>
00331 RES[SCS_NB_WORDS] += t.l;
00332 }
00333 }
00334
00335 <font class="preprocessor">#else </font><font class="comment">/* other architectures */</font>
00336
00337 <font class="comment">/* i=0 */</font>
00338 tmp = X_HW[0];
00339 <font class="keywordflow">for</font>(j=0; j<(SCS_NB_WORDS); j++)
00340 RES[j] += tmp * Y_HW[j];
00341 <font class="comment">/* i = 1..SCS_NB_WORDS-1 */</font>
00342 <font class="keywordflow">for</font>(i=1 ; i<SCS_NB_WORDS; i++){
00343 tmp = X_HW[i];
00344 <font class="keywordflow">for</font>(j=0; j<(SCS_NB_WORDS-i); j++)
00345 RES[i+j] += tmp * Y_HW[j];
00346 RES[SCS_NB_WORDS] += tmp * Y_HW[j]; <font class="comment">/* here j==SCS_NB_WORDS-i */</font>
00347 }
00348 <font class="preprocessor">#endif</font><font class="comment">/* SCS_TYPECPU_X86 */</font>
00349
00350 val = 0;
00351
00352 <font class="comment">/* Carry propagate */</font>
00353 <font class="keywordflow">for</font>(i=SCS_NB_WORDS; i>0; i--)
00354 SCS_CARRY_PROPAGATE(RES[i],RES[i-1],tmp)
00355 SCS_CARRY_PROPAGATE(RES[0],val,tmp)
00356
00357
00358 <font class="comment">/* Store the result */</font>
00359 <font class="keywordflow">if</font>(val != 0){
00360 <font class="comment">/* shift all the digits ! */</font>
00361 R_HW[0] = val;
00362 <font class="keywordflow">for</font>(i=1; i<SCS_NB_WORDS; i++)
00363 R_HW[i] = RES[i-1];
00364
00365 R_IND += 1;
00366 }<font class="keywordflow">else</font> {
00367 <font class="keywordflow">for</font>(i=0; i<SCS_NB_WORDS; i++)
00368 R_HW[i] = RES[i];
00369 }
00370 }
00371
00372
00373
00374
00375
00376
00377
<a name="l00378"></a><a class="code" href="multiplication__scs_8c.html#a3">00378</a> <font class="keywordtype">void</font> <a class="code" href="multiplication__scs_8c.html#a3">scs_square</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <a class="code" href="structscs.html">scs_ptr</a> x){
00379 SCS_CONVERSION_MUL RES[SCS_NB_WORDS+1];
00380 SCS_CONVERSION_MUL val, tmp;
00381 <font class="keywordtype">int</font> i, j;
00382
00383
00384 R_EXP = X_EXP * X_EXP;
00385 R_SGN = 1;
00386 R_IND = X_IND + X_IND;
00387
00388 <font class="comment">/* Set to 0 intermediate register */</font>
00389 <font class="keywordflow">for</font>(i=0; i<=SCS_NB_WORDS; i++)
00390 RES[i] = 0;
00391
00392 <font class="comment">/* Compute all the double partial products: 2 x_i * x_j, i!=j */</font>
00393 tmp = (SCS_CONVERSION_MUL)X_HW[0];
00394 <font class="keywordflow">for</font>(j=1; j<SCS_NB_WORDS; j++)
00395 RES[j] += tmp * X_HW[j];
00396 <font class="keywordflow">for</font>(i=1 ; i<(SCS_NB_WORDS+1)/2; i++){
00397 tmp = (SCS_CONVERSION_MUL)X_HW[i];
00398 <font class="keywordflow">for</font>(j=i+1; j<(SCS_NB_WORDS-i); j++)
00399 RES[i+j] += tmp * X_HW[j];
00400 RES[SCS_NB_WORDS] += tmp * X_HW[SCS_NB_WORDS-i];
00401 }
00402
00403 <font class="comment">/* All these partial products are double */</font>
00404 <font class="keywordflow">for</font>(i=0; i<=SCS_NB_WORDS; i++)
00405 RES[i] *=2;
00406
00407 <font class="comment">/* Add partial product of the form x_i^2 */</font>
00408 <font class="keywordflow">for</font>(i=0, j=0; i<=SCS_NB_WORDS; i+=2, j++){
00409 RES[i] += (SCS_CONVERSION_MUL)X_HW[j] * X_HW[j];
00410 }
00411
00412 val = 0;
00413 <font class="comment">/* Carry propagate */</font>
00414 <font class="keywordflow">for</font>(i=SCS_NB_WORDS; i>0; i--)
00415 SCS_CARRY_PROPAGATE(RES[i],RES[i-1],tmp)
00416
00417 SCS_CARRY_PROPAGATE(RES[0],val,tmp)
00418
00419
00420 <font class="comment">/* Store the result */</font>
00421 <font class="keywordflow">if</font>(val != 0){
00422 <font class="comment">/* shift all the digits ! */</font>
00423 R_HW[0] = val;
00424 <font class="keywordflow">for</font>(i=1; i<SCS_NB_WORDS; i++)
00425 R_HW[i] = RES[i-1];
00426
00427 R_IND += 1;
00428 }<font class="keywordflow">else</font> {
00429 <font class="keywordflow">for</font>(i=0; i<SCS_NB_WORDS; i++)
00430 R_HW[i] = RES[i];
00431 }
00432
00433 }
00434
00435
00436 <font class="comment">/* </font>
00437 <font class="comment"> * #endif corresponding to the test #if (SCS_NB_WORDS==8)</font>
00438 <font class="comment"> */</font>
00439 <font class="preprocessor">#endif</font>
00440 <font class="preprocessor"></font>
00441
00442
00443
00444
00445 <font class="comment">/*</font>
00446 <font class="comment"> Multiply x by an integer val; result is returned in x.</font>
00447 <font class="comment"> */</font>
<a name="l00448"></a><a class="code" href="multiplication__scs_8c.html#a4">00448</a> <font class="keywordtype">void</font> <a class="code" href="multiplication__scs_8c.html#a4">scs_mul_ui</a>(<a class="code" href="structscs.html">scs_ptr</a> x, <font class="keywordtype">unsigned</font> <font class="keywordtype">int</font> val_int){
00449 SCS_CONVERSION_MUL val, tmp, vald, rr;
00450 <font class="keywordtype">int</font> i;
00451
00452 <font class="keywordflow">if</font> (val_int == 0)
00453 X_EXP = 0;
00454
00455 vald = val_int;
00456
00457 val = 0;
00458 rr = 0;
00459 <font class="keywordflow">for</font>(i=(SCS_NB_WORDS-1); i>=0; i--){
00460 val += vald * X_HW[i];
00461 SCS_CARRY_PROPAGATE(val, rr, tmp)
00462 X_HW[i] = val;
00463 val = rr;
00464 rr = 0;
00465 }
00466
00467 <font class="keywordflow">if</font>(val != 0){
00468 <font class="comment">/* shift all the digits ! */</font>
00469 <font class="keywordflow">for</font>(i=(SCS_NB_WORDS-1); i>0; i--)
00470 X_HW[i] = X_HW[i-1];
00471
00472 X_HW[0] = val;
00473 X_IND += 1;
00474 }
00475
00476 <font class="keywordflow">return</font>;
00477 }
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