spielwiese
Last change
on this file since 9c9e2a4 was
9c9e2a4,
checked in by Jens Schmidt <schmidt@…>, 26 years ago
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^M fix. Was:
Thu 27.11.1997 22:30:00 Ruediger Stobbe <rstobbe@de.oracle.com>
Factory Win NT Port, see ChangeLog for details
git-svn-id: file:///usr/local/Singular/svn/trunk@951 2c84dea3-7e68-4137-9b89-c4e89433aadc
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-
Property mode set to
100644
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File size:
1.1 KB
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1 | /* emacs edit mode for this file is -*- C++ -*- */ |
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2 | /* $Id: ffops.cc,v 1.6 1997-12-08 18:24:37 schmidt Exp $ */ |
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3 | |
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4 | #include <config.h> |
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5 | |
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6 | #include "assert.h" |
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7 | |
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8 | #include "cf_defs.h" |
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9 | #include "ffops.h" |
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10 | |
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11 | int ff_prime = 31991; |
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12 | int ff_halfprime = 31991 / 2; |
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13 | bool ff_big = false; |
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14 | short * ff_invtab = new short [32767]; |
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15 | |
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16 | void ff_setprime ( const int p ) |
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17 | { |
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18 | if ( p != ff_prime ) { |
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19 | ff_prime = p; |
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20 | ff_halfprime = ff_prime / 2; |
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21 | if ( ! ff_big ) |
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22 | for ( int i = 0; i < ff_prime; i++ ) ff_invtab[i] = 0; |
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23 | } |
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24 | } |
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25 | |
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26 | int ff_newinv ( const int a ) |
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27 | { |
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28 | int u, r0 = a, r1 = ff_prime, q0 = 1, q1 = 0; |
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29 | while ( ( r0 > 0 ) && ( r1 > 0 ) ) { |
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30 | u = r0 / r1; |
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31 | r0 = r0 % r1; |
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32 | q0 = u*q1 + q0; |
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33 | if ( r0 > 0 ) { |
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34 | u = r1 / r0; |
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35 | r1 = r1 % r0; |
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36 | q1 = u*q0 + q1; |
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37 | } |
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38 | } |
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39 | if ( r0 == 0 ) |
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40 | return (ff_invtab[a] = -q1); |
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41 | else |
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42 | return (ff_invtab[a] = q0); |
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43 | } |
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44 | |
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45 | int ff_biginv ( const int a ) |
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46 | { |
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47 | INT64 u, r0 = a, r1 = ff_prime, q0 = 1, q1 = 0; |
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48 | while ( ( r0 > 0 ) && ( r1 > 0 ) ) { |
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49 | u = r0 / r1; |
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50 | r0 = r0 % r1; |
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51 | q0 = u*q1 + q0; |
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52 | if ( r0 > 0 ) { |
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53 | u = r1 / r0; |
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54 | r1 = r1 % r0; |
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55 | q1 = u*q0 + q1; |
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56 | } |
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57 | } |
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58 | if ( r0 == 0 ) |
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59 | return -(int)q1; |
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60 | else |
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61 | return (int)q0; |
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62 | } |
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