git.distorted.org.uk Git - u/mdw/catacomb/blob - gfx.h

   1 /* -*-c-*-
   2  *
   3  * $Id: gfx.h,v 1.3 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * Low-level arithmetic on binary polynomials
   6  *
   7  * (c) 2000 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 #ifndef CATACOMB_GFX_H
  31 #define CATACOMB_GFX_H
  32
  33 #ifdef __cplusplus
  34   extern "C" {
  35 #endif
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #ifndef CATACOMB_MPX_H
  40 #  include "mpx.h"
  41 #endif
  42
  43 /*----- Functions provided ------------------------------------------------*/
  44
  45 /* --- @gfx_add@ --- *
  46  *
  47  * Arguments:   @mpw *dv, *dvl@ = destination vector base and limit
  48  *              @const mpw *av, *avl@ = first addend vector base and limit
  49  *              @const mpw *bv, *bvl@ = second addend vector base and limit
  50  *
  51  * Returns:     ---
  52  *
  53  * Use:         Adds two %$\gf{2}$% polynomials.  This is the same as
  54  *              subtraction.
  55  */
  56
  57 extern void gfx_add(mpw */*dv*/, mpw */*dvl*/,
  58                     const mpw */*av*/, const mpw */*avl*/,
  59                     const mpw */*bv*/, const mpw */*bvl*/);
  60
  61 /* --- @gfx_acc@ --- *
  62  *
  63  * Arguments:   @mpw *dv, *dvl@ = destination vector base and limit
  64  *              @const mpw *av, *avl@ = addend vector base and limit
  65  *
  66  * Returns:     ---
  67  *
  68  * Use:         Adds the addend into the destination.  This is considerably
  69  *              faster than the three-address add call.
  70  */
  71
  72 extern void gfx_acc(mpw */*dv*/, mpw */*dvl*/,
  73                     const mpw */*av*/, const mpw */*avl*/);
  74
  75 /* --- @gfx_accshift@ --- *
  76  *
  77  * Arguments:   @mpw *dv, *dvl@ = destination vector base and limit
  78  *              @const mpw *av, *avl@ = addend vector base and limit
  79  *              @size_t n@ = number of bits to shift
  80  *
  81  * Returns:     ---
  82  *
  83  * Use:         Shifts the argument left by %$n$% places and adds it to the
  84  *              destination.  This is a primitive used by multiplication and
  85  *              division.
  86  */
  87
  88 extern void gfx_accshift(mpw */*dv*/, mpw */*dvl*/,
  89                          const mpw */*av*/, const mpw */*avl*/,
  90                          size_t /*n*/);
  91
  92 /* --- @gfx_mul@ --- *
  93  *
  94  * Arguments:   @mpw *dv, *dvl@ = destination vector base and limit
  95  *              @const mpw *av, *avl@ = first argument vector base and limit
  96  *              @const mpw *bv, *bvl@ = second argument vector base and limit
  97  *
  98  * Returns:     ---
  99  *
 100  * Use:         Does multiplication of polynomials over %$\gf{2}$%.
 101  */
 102
 103 extern void gfx_mul(mpw */*dv*/, mpw */*dvl*/,
 104                     const mpw */*av*/, const mpw */*avl*/,
 105                     const mpw */*bv*/, const mpw */*bvl*/);
 106
 107 /* --- @gfx_sqr@ --- *
 108  *
 109  * Arguments:   @mpw *dv, *dvl@ = destination vector base and limit
 110  *              @const mpw *av, *avl@ = argument vector base and limit
 111  *
 112  * Returns:     ---
 113  *
 114  * Use:         Performs squaring of binary polynomials.
 115  */
 116
 117 extern void gfx_sqr(mpw */*dv*/, mpw */*dvl*/,
 118                     const mpw */*av*/, const mpw */*avl*/);
 119
 120 /* --- @gfx_div@ --- *
 121  *
 122  * Arguments:   @mpw *qv, *qvl@ = quotient vector base and limit
 123  *              @mpw *rv, *rvl@ = dividend/remainder vector base and limit
 124  *              @const mpw *dv, *dvl@ = divisor vector base and limit
 125  *
 126  * Returns:     ---
 127  *
 128  * Use:         Performs division on polynomials over %$\gf{2}$%.
 129  */
 130
 131 extern void gfx_div(mpw */*qv*/, mpw */*qvl*/, mpw */*rv*/, mpw */*rvl*/,
 132                     const mpw */*dv*/, const mpw */*dvl*/);
 133
 134 /*----- Karatsuba multiplication algorithms -------------------------------*/
 135
 136 /* --- @GFK_THRESH@ --- *
 137  *
 138  * This is the limiting length for using Karatsuba algorithms.  It's best to
 139  * use the simpler classical multiplication method on numbers smaller than
 140  * this.
 141  */
 142
 143 #define GFK_THRESH 2
 144
 145 /* --- @gfx_kmul@ --- *
 146  *
 147  * Arguments:   @mpw *dv, *dvl@ = pointer to destination buffer
 148  *              @const mpw *av, *avl@ = pointer to first argument
 149  *              @const mpw *bv, *bvl@ = pointer to second argument
 150  *              @mpw *sv, *svl@ = pointer to scratch workspace
 151  *
 152  * Returns:     ---
 153  *
 154  * Use:         Multiplies two binary polynomials using Karatsuba's
 155  *              algorithm.  This is rather faster than traditional long
 156  *              multiplication (e.g., @gfx_umul@) on polynomials with large
 157  *              degree, although more expensive on small ones.
 158  *
 159  *              The destination must be twice as large as the larger
 160  *              argument.  The scratch space must be twice as large as the
 161  *              larger argument.
 162  */
 163
 164 extern void gfx_kmul(mpw */*dv*/, mpw */*dvl*/,
 165                      const mpw */*av*/, const mpw */*avl*/,
 166                      const mpw */*bv*/, const mpw */*bvl*/,
 167                      mpw */*sv*/, mpw */*svl*/);
 168
 169 /*----- That's all, folks -------------------------------------------------*/
 170
 171 #ifdef __cplusplus
 172   }
 173 #endif
 174
 175 #endif