ocaml/otherlibs/num/bng.h

157 lines
5.6 KiB
C

/***********************************************************************/
/* */
/* Objective Caml */
/* */
/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
/* */
/* Copyright 2003 Institut National de Recherche en Informatique et */
/* en Automatique. All rights reserved. This file is distributed */
/* under the terms of the GNU Library General Public License, with */
/* the special exception on linking described in file ../../LICENSE. */
/* */
/***********************************************************************/
/* $Id$ */
#include <string.h>
#include "config.h"
typedef uintnat bngdigit;
typedef bngdigit * bng;
typedef unsigned int bngcarry;
typedef uintnat bngsize;
#define BNG_BITS_PER_DIGIT (sizeof(bngdigit) * 8)
#define BNG_BITS_PER_HALF_DIGIT (sizeof(bngdigit) * 4)
struct bng_operations {
/* {a,alen} := {a, alen} + carry. Return carry out. */
bngcarry (*add_carry)
(bng a/*[alen]*/, bngsize alen, bngcarry carry);
#define bng_add_carry bng_ops.add_carry
/* {a,alen} := {a,alen} + {b,blen} + carry. Return carry out.
Require alen >= blen. */
bngcarry (*add)
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngcarry carry);
#define bng_add bng_ops.add
/* {a,alen} := {a, alen} - carry. Return carry out. */
bngcarry (*sub_carry)
(bng a/*[alen]*/, bngsize alen, bngcarry carry);
#define bng_sub_carry bng_ops.sub_carry
/* {a,alen} := {a,alen} - {b,blen} - carry. Return carry out.
Require alen >= blen. */
bngcarry (*sub)
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngcarry carry);
#define bng_sub bng_ops.sub
/* {a,alen} := {a,alen} << shift.
Return the bits shifted out of the most significant digit of a.
Require 0 <= shift < BITS_PER_BNGDIGIT. */
bngdigit (*shift_left)
(bng a/*[alen]*/, bngsize alen,
int shift);
#define bng_shift_left bng_ops.shift_left
/* {a,alen} := {a,alen} >> shift.
Return the bits shifted out of the least significant digit of a.
Require 0 <= shift < BITS_PER_BNGDIGIT. */
bngdigit (*shift_right)
(bng a/*[alen]*/, bngsize alen,
int shift);
#define bng_shift_right bng_ops.shift_right
/* {a,alen} := {a,alen} + d * {b,blen}. Return carry out.
Require alen >= blen.
If alen > blen, the carry out returned is 0 or 1.
If alen == blen, the carry out returned is a full digit. */
bngdigit (*mult_add_digit)
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngdigit d);
#define bng_mult_add_digit bng_ops.mult_add_digit
/* {a,alen} := {a,alen} - d * {b,blen}. Return carry out.
Require alen >= blen.
If alen > blen, the carry out returned is 0 or 1.
If alen == blen, the carry out returned is a full digit. */
bngdigit (*mult_sub_digit)
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngdigit d);
#define bng_mult_sub_digit bng_ops.mult_sub_digit
/* {a,alen} := {a,alen} + {b,blen} * {c,clen}. Return carry out.
Require alen >= blen + clen. */
bngcarry (*mult_add)
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bng c/*[clen]*/, bngsize clen);
#define bng_mult_add bng_ops.mult_add
/* {a,alen} := 2 * {a,alen} + {b,blen}^2. Return carry out.
Require alen >= 2 * blen. */
bngcarry (*square_add)
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen);
#define bng_square_add bng_ops.square_add
/* {a,len-1} := {b,len} / d. Return {b,len} modulo d.
Require d is normalized and MSD of b < d.
See div_rem_digit for a function that does not require d
to be normalized */
bngdigit (*div_rem_norm_digit)
(bng a/*[len-1]*/, bng b/*[len]*/, bngsize len, bngdigit d);
#define bng_div_rem_norm_digit bng_ops.div_rem_norm_digit
/* {a,len-1} := {b,len} / d. Return {b,len} modulo d.
Require MSD of b < d. */
bngdigit (*div_rem_digit)
(bng a/*[len-1]*/, bng b/*[len]*/, bngsize len, bngdigit d);
#define bng_div_rem_digit bng_ops.div_rem_digit
/* {n+dlen, nlen-dlen} := {n,nlen} / {d, dlen}.
{n, dlen} := {n,nlen} modulo {d, dlen}.
Require nlen > dlen and MSD of n < MSD of d (which implies d != 0). */
void (*div_rem)
(bng n/*[nlen]*/, bngsize nlen,
bng d/*[nlen]*/, bngsize dlen);
#define bng_div_rem bng_ops.div_rem
};
extern struct bng_operations bng_ops;
/* Initialize the BNG library */
extern void bng_init(void);
/* {a,alen} := 0 */
#define bng_zero(a,alen) memset((a), 0, (alen) * sizeof(bngdigit))
/* {a,len} := {b,len} */
#define bng_assign(a,b,len) memmove((a), (b), (len) * sizeof(bngdigit))
/* Complement the digits of {a,len} */
extern void bng_complement(bng a/*[alen]*/, bngsize alen);
/* Return number of significant digits in {a,alen}. */
extern bngsize bng_num_digits(bng a/*[alen]*/, bngsize alen);
/* Return 1 if {a,alen} is 0, 0 otherwise. */
#define bng_is_zero(a,alen) (bng_num_digits(a,alen) == 0)
/* Return 0 if {a,alen} = {b,blen}
<0 if {a,alen} < {b,blen}
>0 if {a,alen} > {b,blen}. */
extern int bng_compare(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen);
/* Return the number of leading zero bits in digit d. */
extern int bng_leading_zero_bits(bngdigit d);