[u/mdw/catacomb] / mpx.h

/* -*-c-*-
 *
 * $Id: mpx.h,v 1.4 1999/11/17 18:04:43 mdw Exp $
 *
 * Low level multiprecision arithmetic
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * Catacomb is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: mpx.h,v $
 * Revision 1.4  1999/11/17 18:04:43  mdw
 * Add two's complement support.  Fix a bug in MPX_UMLAN.
 *
 * Revision 1.3  1999/11/13 01:51:29  mdw
 * Minor interface changes.  Should be stable now.
 *
 * Revision 1.2  1999/11/11 17:47:55  mdw
 * Minor changes for different `mptypes.h' format.
 *
 * Revision 1.1  1999/09/03 08:41:12  mdw
 * Initial import.
 *
 */

#ifndef MPX_H
#define MPX_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- The idea ----------------------------------------------------------*
 *
 * This file provides functions and macros which work on vectors of words as
 * unsigned multiprecision integers.  The interface works in terms of base
 * and limit pointers (i.e., a pointer to the start of a vector, and a
 * pointer just past its end) rather than base pointer and length, because
 * that requires more arithmetic and state to work on.
 *
 * The interfaces are slightly bizarre in other ways.  Try to use the
 * higher-level functions where you can: they're rather better designed to
 * actually be friendly and useful.
 */

/*----- Header files ------------------------------------------------------*/

#include <string.h>

#ifndef MPW_H
#  include "mpw.h"
#endif

/*----- General manipulation ----------------------------------------------*/

/* --- @MPX_SHRINK@ --- *
 *
 * Arguments:	@const mpw *v@ = pointer to vector of words
 *		@const mpw *vl@ = (updated) current limit of vector
 *
 * Use:		Shrinks down the limit of a multiprecision integer vector.
 */

#define MPX_SHRINK(v, vl) do {						\
  const mpw *_vv = (v), *_vvl = (vl);					\
  while (_vvl > _vv && !_vvl[-1])					\
    _vvl--;								\
  (vl) = (mpw *)_vvl;							\
} while (0)

/* --- @MPX_BITS@ --- *
 *
 * Arguments:	@unsigned long b@ = result variable
 *		@const mpw *v@ = pointer to array of words
 *		@const mpw *vl@ = limit of vector (from @MPX_SHRINK@)
 *
 * Use:		Calculates the number of bits in a multiprecision value.
 */

#define MPX_BITS(b, v, vl) do {						\
  const mpw *_v = (v), *_vl = (vl);					\
  MPX_SHRINK(_v, _vl);							\
  if (_v == _vl)							\
    (b) = 0;								\
  else {								\
    unsigned long _b = MPW_BITS * (_vl - _v - 1) + 1;	       		\
    mpw _w = _vl[-1];							\
    unsigned _k = MPW_BITS / 2;						\
    while (_k) {							\
      if (_w >> _k) {							\
	_w >>= _k;							\
	_b += _k;							\
      }									\
      _k >>= 1;								\
    }									\
    (b) = _b;								\
  }									\
} while (0)

/* --- @MPX_OCTETS@ --- *
 *
 * Arguments:	@size_t o@ = result variable
 *		@const mpw *v, *vl@ = pointer to array of words
 *
 * Use:		Calculates the number of octets in a multiprecision value.
 */

#define MPX_OCTETS(o, v, vl) do {					\
  const mpw *_v = (v), *_vl = (vl);					\
  MPX_SHRINK(_v, _vl);							\
  if (_v == _vl)							\
    (o) = 0;								\
  else {								\
    size_t _o = (MPW_BITS / 8) * (_vl - _v - 1);			\
    mpw _w = _vl[-1];							\
    unsigned _k = MPW_BITS / 2;						\
    while (_k >= 8) {							\
      if (_w >> _k) {							\
	_w >>= _k;							\
	_o += _k >> 3;							\
      }									\
      _k >>= 1;								\
    }									\
    if (_w)								\
      _o++;								\
    (o) = _o;								\
  }									\
} while (0)

/* --- @MPX_COPY@ --- *
 *
 * Arguments:	@dv, dvl@ = destination vector base and limit
 *		@av, avl@ = source vector base and limit
 *
 * Use:		Copies a multiprecision integer.
 */

#define MPX_COPY(dv, dvl, av, avl) do {					\
  mpw *_dv = (dv), *_dvl = (dvl);					\
  size_t _dn = _dvl - _dv;						\
  const mpw *_av = (av), *_avl = (avl);					\
  size_t _an = _avl - _av;						\
  if (_av == _dv) {							\
    if (_dvl > _avl)							\
      memset(_dv, 0, MPWS(_dn - _an));					\
  } else if (_an >= _dn)						\
    memmove(_dv, _av, MPWS(_dn));					\
  else {								\
    memmove(_dv, _av, MPWS(_an));					\
    memset(_dv + _an, 0, MPWS(_dn - _an));				\
  }									\
} while (0)

/* --- @MPX_ZERO@ --- *
 *
 * Arguments:	@v, vl@ = base and limit of vector to clear
 *
 * Use:		Zeroes the area between the two vector pointers.
 */

#define MPX_ZERO(v, vl) do {						\
  mpw *_v = (v), *_vl = (vl);						\
  if (_v < _vl)								\
    memset(_v, 0, MPWS(_vl - _v));					\
} while (0)

/*----- Loading and storing -----------------------------------------------*/

/* --- @mpx_storel@ --- *
 *
 * Arguments:	@const mpw *v, *vl@ = base and limit of source vector
 *		@void *p@ = pointer to octet array
 *		@size_t sz@ = size of octet array
 *
 * Returns:	---
 *
 * Use:		Stores an MP in an octet array, least significant octet
 *		first.  High-end octets are silently discarded if there
 *		isn't enough space for them.
 */

extern void mpx_storel(const mpw */*v*/, const mpw */*vl*/,
		       void */*p*/, size_t /*sz*/);

/* --- @mpx_loadl@ --- *
 *
 * Arguments:	@mpw *v, *vl@ = base and limit of destination vector
 *		@const void *p@ = pointer to octet array
 *		@size_t sz@ = size of octet array
 *
 * Returns:	---
 *
 * Use:		Loads an MP in an octet array, least significant octet
 *		first.  High-end octets are ignored if there isn't enough
 *		space for them.
 */

extern void mpx_loadl(mpw */*v*/, mpw */*vl*/,
		      const void */*p*/, size_t /*sz*/);

/* --- @mpx_storeb@ --- *
 *
 * Arguments:	@const mpw *v, *vl@ = base and limit of source vector
 *		@void *p@ = pointer to octet array
 *		@size_t sz@ = size of octet array
 *
 * Returns:	---
 *
 * Use:		Stores an MP in an octet array, most significant octet
 *		first.  High-end octets are silently discarded if there
 *		isn't enough space for them.
 */

extern void mpx_storeb(const mpw */*v*/, const mpw */*vl*/,
		       void */*p*/, size_t /*sz*/);

/* --- @mpx_loadb@ --- *
 *
 * Arguments:	@mpw *v, *vl@ = base and limit of destination vector
 *		@const void *p@ = pointer to octet array
 *		@size_t sz@ = size of octet array
 *
 * Returns:	---
 *
 * Use:		Loads an MP in an octet array, most significant octet
 *		first.  High-end octets are ignored if there isn't enough
 *		space for them.
 */

extern void mpx_loadb(mpw */*v*/, mpw */*vl*/,
		      const void */*p*/, size_t /*sz*/);

/*----- Logical shifting --------------------------------------------------*/

/* --- @mpx_lsl@ --- *
 *
 * Arguments:	@mpw *dv, *dvl@ = destination vector base and limit
 *		@const mpw *av, *avl@ = source vector base and limit
 *		@size_t n@ = number of bit positions to shift by
 *
 * Returns:	---
 *
 * Use:		Performs a logical shift left operation on an integer.
 */

extern void mpx_lsl(mpw */*dv*/, mpw */*dvl*/,
		    const mpw */*av*/, const mpw */*avl*/,
		    size_t /*n*/);

/* --- @mpx_lsr@ --- *
 *
 * Arguments:	@mpw *dv, *dvl@ = destination vector base and limit
 *		@const mpw *av, *avl@ = source vector base and limit
 *		@size_t n@ = number of bit positions to shift by
 *
 * Returns:	---
 *
 * Use:		Performs a logical shift right operation on an integer.
 */

extern void mpx_lsr(mpw */*dv*/, mpw */*dvl*/,
		    const mpw */*av*/, const mpw */*avl*/,
		    size_t /*n*/);

/*----- Unsigned arithmetic -----------------------------------------------*/

/* --- @mpx_2c@ --- *
 *
 * Arguments:	@mpw *dv, *dvl@ = destination vector
 *		@const mpw *v, *vl@ = source vector
 *
 * Returns:	---
 *
 * Use:		Calculates the two's complement of @v@.
 */

extern void mpx_2c(mpw */*dv*/, mpw */*dvl*/,
		   const mpw */*v*/, const mpw */*vl*/);

/* --- @mpx_ucmp@ --- *
 *
 * Arguments:	@const mpw *av, *avl@ = first argument vector base and limit
 *		@const mpw *bv, *bvl@ = second argument vector base and limit
 *
 * Returns:	Less than, equal to, or greater than zero depending on
 *		whether @a@ is less than, equal to or greater than @b@,
 *		respectively.
 *
 * Use:		Performs an unsigned integer comparison.
 */

#define MPX_UCMP(av, avl, op, dv, dvl)					\
  (mpx_ucmp((av), (avl), (dv), (dvl)) op 0)

extern int mpx_ucmp(const mpw */*av*/, const mpw */*avl*/,
		    const mpw */*bv*/, const mpw */*bvl*/);

/* --- @mpx_uadd@ --- *
 *
 * Arguments:	@mpw *dv, *dvl@ = destination vector base and limit
 *		@const mpw *av, *avl@ = first addend vector base and limit
 *		@const mpw *bv, *bvl@ = second addend vector base and limit
 *
 * Returns:	---
 *
 * Use:		Performs unsigned integer addition.  If the result overflows
 *		the destination vector, high-order bits are discarded.  This
 *		means that two's complement addition happens more or less for
 *		free, although that's more a side-effect than anything else.
 *		The result vector may be equal to either or both source
 *		vectors, but may not otherwise overlap them.
 */

extern void mpx_uadd(mpw */*dv*/, mpw */*dvl*/,
		     const mpw */*av*/, const mpw */*avl*/,
		     const mpw */*bv*/, const mpw */*bvl*/);

/* --- @MPX_UADDN@ --- *
 *
 * Arguments:	@dv, dvl@ = source and destination vector base and limit
 *		@n@ = other addend
 *
 * Use:		Adds a small integer to a multiprecision number.
 */

#define MPX_UADDN(dv, dvl, n) do {					\
  mpw *_ddv = (dv), *_ddvl = (dvl);					\
  mpw _c = (n);								\
									\
  while (_c && _ddv < _ddvl) {						\
    mpd _x = (mpd)*_ddv + (mpd)_c;					\
    *_ddv++ = MPW(_x);							\
    _c = _x >> MPW_BITS;						\
  }									\
} while (0)

/* --- @mpx_usub@ --- *
 *
 * Arguments:	@mpw *dv, *dvl@ = destination vector base and limit
 *		@const mpw *av, *avl@ = first argument vector base and limit
 *		@const mpw *bv, *bvl@ = second argument vector base and limit
 *
 * Returns:	---
 *
 * Use:		Performs unsigned integer subtraction.  If the result
 *		overflows the destination vector, high-order bits are
 *		discarded.  This means that two's complement subtraction
 *		happens more or less for free, although that's more a side-
 *		effect than anything else.  The result vector may be equal to
 *		either or both source vectors, but may not otherwise overlap
 *		them.
 */

extern void mpx_usub(mpw */*dv*/, mpw */*dvl*/,
		     const mpw */*av*/, const mpw */*avl*/,
		     const mpw */*bv*/, const mpw */*bvl*/);

/* --- @MPX_USUBN@ --- *
 *
 * Arguments:	@@dv, dvl@ = destination vector base and limit
 *		@n@ = other addend
 *
 * Use:		Subtracts a small integer from a multiprecision number.
 */

#define MPX_USUBN(dv, dvl, n) do {					\
  mpw *_ddv = (dv), *_ddvl = (dvl);					\
  mpw _c = (n);								\
									\
  while (_ddv < _ddvl) {						\
    mpd _x = (mpd)*_ddv - (mpd)_c;					\
    *_ddv++ = MPW(_x);							\
    if (_x >> MPW_BITS)							\
      _c = 1;								\
    else								\
      break;								\
  }									\
} while (0)

/* --- @mpx_umul@ --- *
 *
 * Arguments:	@mpw *dv, *dvl@ = destination vector base and limit
 *		@const mpw *av, *avl@ = multiplicand vector base and limit
 *		@const mpw *bv, *bvl@ = multiplier vector base and limit
 *
 * Returns:	---
 *
 * Use:		Performs unsigned integer multiplication.  If the result
 *		overflows the desination vector, high-order bits are
 *		discarded.  The result vector may not overlap the argument
 *		vectors in any way.
 */

extern void mpx_umul(mpw */*dv*/, mpw */*dvl*/,
		     const mpw */*av*/, const mpw */*avl*/,
		     const mpw */*bv*/, const mpw */*bvl*/);

/* --- @MPX_UMULN@ --- *
 *
 * Arguments:	@dv, dvl@ = destination vector base and limit
 *		@av, avl@ = multiplicand vector base and limit
 *		@m@ = multiplier
 *
 * Use:		Multiplies a multiprecision integer by a single-word value.
 *		The destination and source may be equal.  The destination
 *		is completely cleared after use.
 */

#define MPX_UMULN(dv, dvl, av, avl, m) do {				\
  mpw *_dv = (dv), *_dvl = (dvl);					\
  const mpw *_av = (av), *_avl = (avl);					\
  mpw _c = 0;								\
  mpd _m = (m);								\
									\
  while (_av < _avl) {							\
    mpd _x;								\
    if (_dv >= _dvl)							\
      break;								\
    _x = (mpd)_m * (mpd)*_av++ + _c;					\
    *_dv++ = MPW(_x);							\
    _c = _x >> MPW_BITS;						\
  }									\
  if (_dv < _dvl) {							\
    *_dv++ = MPW(_c);							\
    MPX_ZERO(_dv, _dvl);						\
  }									\
} while (0)

/* --- @MPX_UMLAN@ --- *
 *
 * Arguments:	@dv, dvl@ = destination/accumulator vector base and limit
 *		@av, avl@ = multiplicand vector base and limit
 *		@m@ = multiplier
 *
 * Use:		Multiplies a multiprecision integer by a single-word value
 *		and adds the result to an accumulator.
 */

#define MPX_UMLAN(dv, dvl, av, avl, m) do {				\
  mpw *_dv = (dv), *_dvl = (dvl);					\
  const mpw *_av = (av), *_avl = (avl);					\
  mpw _cc = 0;								\
  mpd _m = (m);								\
									\
  while (_av < _avl) {							\
    mpd _x;								\
    if (_dv >= _dvl)							\
      break;								\
    _x = (mpd)*_dv + (mpd)_m * (mpd)*_av++ + _cc;			\
    *_dv++ = MPW(_x);							\
    _cc = _x >> MPW_BITS;						\
  }									\
  MPX_UADDN(_dv, _dvl, _cc);						\
} while (0)

/* --- @mpx_usqr@ --- *
 *
 * Arguments:	@mpw *dv, *dvl@ = destination vector base and limit
 *		@const mpw *av, *av@ = source vector base and limit
 *
 * Returns:	---
 *
 * Use:		Performs unsigned integer squaring.  The result vector must
 *		not overlap the source vector in any way.
 */

extern void mpx_usqr(mpw */*dv*/, mpw */*dvl*/,
		     const mpw */*av*/, const mpw */*avl*/);

/* --- @mpx_udiv@ --- *
 *
 * Arguments:	@mpw *qv, *qvl@ = quotient vector base and limit
 *		@mpw *rv, *rvl@ = dividend/remainder vector base and limit
 *		@const mpw *dv, *dvl@ = divisor vector base and limit
 *		@mpw *sv, *svl@ = scratch workspace 
 *
 * Returns:	---
 *
 * Use:		Performs unsigned integer division.  If the result overflows
 *		the quotient vector, high-order bits are discarded.  (Clearly
 *		the remainder vector can't overflow.)  The various vectors
 *		may not overlap in any way.  Yes, I know it's a bit odd
 *		requiring the dividend to be in the result position but it
 *		does make some sense really.  The remainder must have
 *		headroom for at least two extra words.  The scratch space
 *		must be at least one word larger than the divisor.
 */

extern void mpx_udiv(mpw */*qv*/, mpw */*qvl*/, mpw */*rv*/, mpw */*rvl*/,
		     const mpw */*dv*/, const mpw */*dvl*/,
		     mpw */*sv*/, mpw */*svl*/);

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif
Commit	Line	Data
d03ab969	1	/* --c--
d03ab969	2	*
7c13f461	3	* $Id: mpx.h,v 1.4 1999/11/17 18:04:43 mdw Exp $
d03ab969	4	*
	5	* Low level multiprecision arithmetic
	6	*
	7	* (c) 1999 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	/----- Revision history --------------------------------------------------
	31	*
	32	* $Log: mpx.h,v $
7c13f461	33	* Revision 1.4 1999/11/17 18:04:43 mdw
	34	* Add two's complement support. Fix a bug in MPX_UMLAN.
	35	*
3c9ede17	36	* Revision 1.3 1999/11/13 01:51:29 mdw
	37	* Minor interface changes. Should be stable now.
	38	*
b9b1c853	39	* Revision 1.2 1999/11/11 17:47:55 mdw
	40	* Minor changes for different `mptypes.h' format.
	41	*
d03ab969	42	* Revision 1.1 1999/09/03 08:41:12 mdw
	43	* Initial import.
	44	*
	45	*/
	46
	47	#ifndef MPX_H
	48	#define MPX_H
	49
	50	#ifdef __cplusplus
	51	extern "C" {
	52	#endif
	53
	54	/----- The idea ----------------------------------------------------------
	55	*
	56	* This file provides functions and macros which work on vectors of words as
	57	* unsigned multiprecision integers. The interface works in terms of base
	58	* and limit pointers (i.e., a pointer to the start of a vector, and a
	59	* pointer just past its end) rather than base pointer and length, because
	60	* that requires more arithmetic and state to work on.
	61	*
	62	* The interfaces are slightly bizarre in other ways. Try to use the
	63	* higher-level functions where you can: they're rather better designed to
	64	* actually be friendly and useful.
	65	*/
	66
	67	/----- Header files ------------------------------------------------------/
	68
	69	#include <string.h>
	70
3c9ede17	71	#ifndef MPW_H
3c9ede17	72	# include "mpw.h"
d03ab969	73	#endif
	74
	75	/----- General manipulation ----------------------------------------------/
	76
	77	/* --- @MPX_SHRINK@ --- *
	78	*
	79	* Arguments: @const mpw *v@ = pointer to vector of words
	80	* @const mpw *vl@ = (updated) current limit of vector
	81	*
	82	* Use: Shrinks down the limit of a multiprecision integer vector.
	83	*/
	84
	85	#define MPX_SHRINK(v, vl) do { \
3c9ede17	86	const mpw _vv = (v), _vvl = (vl); \
	87	while (_vvl > _vv && !_vvl[-1]) \
	88	_vvl--; \
	89	(vl) = (mpw *)_vvl; \
d03ab969	90	} while (0)
	91
	92	/* --- @MPX_BITS@ --- *
	93	*
	94	* Arguments: @unsigned long b@ = result variable
	95	* @const mpw *v@ = pointer to array of words
	96	* @const mpw *vl@ = limit of vector (from @MPX_SHRINK@)
	97	*
	98	* Use: Calculates the number of bits in a multiprecision value.
	99	*/
	100
	101	#define MPX_BITS(b, v, vl) do { \
	102	const mpw _v = (v), _vl = (vl); \
3c9ede17	103	MPX_SHRINK(_v, _vl); \
d03ab969	104	if (_v == _vl) \
	105	(b) = 0; \
	106	else { \
	107	unsigned long _b = MPW_BITS * (_vl - _v - 1) + 1; \
	108	mpw _w = _vl[-1]; \
	109	unsigned _k = MPW_BITS / 2; \
	110	while (_k) { \
	111	if (_w >> _k) { \
	112	_w >>= _k; \
	113	_b += _k; \
	114	} \
	115	_k >>= 1; \
	116	} \
	117	(b) = _b; \
	118	} \
	119	} while (0)
	120
	121	/* --- @MPX_OCTETS@ --- *
	122	*
	123	* Arguments: @size_t o@ = result variable
3c9ede17	124	* @const mpw v, vl@ = pointer to array of words
d03ab969	125	*
	126	* Use: Calculates the number of octets in a multiprecision value.
	127	*/
	128
3c9ede17	129	#define MPX_OCTETS(o, v, vl) do { \
d03ab969	130	const mpw _v = (v), _vl = (vl); \
3c9ede17	131	MPX_SHRINK(_v, _vl); \
d03ab969	132	if (_v == _vl) \
	133	(o) = 0; \
	134	else { \
3c9ede17	135	size_t _o = (MPW_BITS / 8) * (_vl - _v - 1); \
d03ab969	136	mpw _w = _vl[-1]; \
d03ab969	137	unsigned _k = MPW_BITS / 2; \
3c9ede17	138	while (_k >= 8) { \
d03ab969	139	if (_w >> _k) { \
d03ab969	140	_w >>= _k; \
3c9ede17	141	_o += _k >> 3; \
d03ab969	142	} \
	143	_k >>= 1; \
	144	} \
	145	if (_w) \
	146	_o++; \
	147	(o) = _o; \
	148	} \
	149	} while (0)
	150
	151	/* --- @MPX_COPY@ --- *
	152	*
	153	* Arguments: @dv, dvl@ = destination vector base and limit
	154	* @av, avl@ = source vector base and limit
	155	*
	156	* Use: Copies a multiprecision integer.
	157	*/
	158
3c9ede17	159	#define MPX_COPY(dv, dvl, av, avl) do { \
	160	mpw _dv = (dv), _dvl = (dvl); \
	161	size_t _dn = _dvl - _dv; \
	162	const mpw _av = (av), _avl = (avl); \
	163	size_t _an = _avl - _av; \
d03ab969	164	if (_av == _dv) { \
d03ab969	165	if (_dvl > _avl) \
3c9ede17	166	memset(_dv, 0, MPWS(_dn - _an)); \
d03ab969	167	} else if (_an >= _dn) \
	168	memmove(_dv, _av, MPWS(_dn)); \
	169	else { \
	170	memmove(_dv, _av, MPWS(_an)); \
	171	memset(_dv + _an, 0, MPWS(_dn - _an)); \
	172	} \
	173	} while (0)
	174
	175	/* --- @MPX_ZERO@ --- *
	176	*
	177	* Arguments: @v, vl@ = base and limit of vector to clear
	178	*
	179	* Use: Zeroes the area between the two vector pointers.
	180	*/
	181
3c9ede17	182	#define MPX_ZERO(v, vl) do { \
d03ab969	183	mpw _v = (v), _vl = (vl); \
3c9ede17	184	if (_v < _vl) \
3c9ede17	185	memset(_v, 0, MPWS(_vl - _v)); \
d03ab969	186	} while (0)
	187
	188	/----- Loading and storing -----------------------------------------------/
	189
	190	/* --- @mpx_storel@ --- *
	191	*
	192	* Arguments: @const mpw v, vl@ = base and limit of source vector
3c9ede17	193	* @void *p@ = pointer to octet array
d03ab969	194	* @size_t sz@ = size of octet array
	195	*
	196	* Returns: ---
	197	*
	198	* Use: Stores an MP in an octet array, least significant octet
	199	* first. High-end octets are silently discarded if there
	200	* isn't enough space for them.
	201	*/
	202
	203	extern void mpx_storel(const mpw /v/, const mpw /vl/,
3c9ede17	204	void /p/, size_t /sz*/);
d03ab969	205
	206	/* --- @mpx_loadl@ --- *
	207	*
	208	* Arguments: @mpw v, vl@ = base and limit of destination vector
3c9ede17	209	* @const void *p@ = pointer to octet array
d03ab969	210	* @size_t sz@ = size of octet array
	211	*
	212	* Returns: ---
	213	*
	214	* Use: Loads an MP in an octet array, least significant octet
	215	* first. High-end octets are ignored if there isn't enough
	216	* space for them.
	217	*/
	218
	219	extern void mpx_loadl(mpw /v/, mpw /vl/,
3c9ede17	220	const void /p/, size_t /sz*/);
d03ab969	221
	222	/* --- @mpx_storeb@ --- *
	223	*
	224	* Arguments: @const mpw v, vl@ = base and limit of source vector
3c9ede17	225	* @void *p@ = pointer to octet array
d03ab969	226	* @size_t sz@ = size of octet array
	227	*
	228	* Returns: ---
	229	*
	230	* Use: Stores an MP in an octet array, most significant octet
	231	* first. High-end octets are silently discarded if there
	232	* isn't enough space for them.
	233	*/
	234
	235	extern void mpx_storeb(const mpw /v/, const mpw /vl/,
3c9ede17	236	void /p/, size_t /sz*/);
d03ab969	237
	238	/* --- @mpx_loadb@ --- *
	239	*
	240	* Arguments: @mpw v, vl@ = base and limit of destination vector
3c9ede17	241	* @const void *p@ = pointer to octet array
d03ab969	242	* @size_t sz@ = size of octet array
	243	*
	244	* Returns: ---
	245	*
	246	* Use: Loads an MP in an octet array, most significant octet
	247	* first. High-end octets are ignored if there isn't enough
	248	* space for them.
	249	*/
	250
	251	extern void mpx_loadb(mpw /v/, mpw /vl/,
3c9ede17	252	const void /p/, size_t /sz*/);
d03ab969	253
	254	/----- Logical shifting --------------------------------------------------/
	255
	256	/* --- @mpx_lsl@ --- *
	257	*
	258	* Arguments: @mpw dv, dvl@ = destination vector base and limit
	259	* @const mpw av, avl@ = source vector base and limit
	260	* @size_t n@ = number of bit positions to shift by
	261	*
	262	* Returns: ---
	263	*
	264	* Use: Performs a logical shift left operation on an integer.
	265	*/
	266
	267	extern void mpx_lsl(mpw /dv/, mpw /dvl/,
	268	const mpw /av/, const mpw /avl/,
	269	size_t /n/);
	270
	271	/* --- @mpx_lsr@ --- *
	272	*
	273	* Arguments: @mpw dv, dvl@ = destination vector base and limit
	274	* @const mpw av, avl@ = source vector base and limit
	275	* @size_t n@ = number of bit positions to shift by
	276	*
	277	* Returns: ---
	278	*
	279	* Use: Performs a logical shift right operation on an integer.
	280	*/
	281
	282	extern void mpx_lsr(mpw /dv/, mpw /dvl/,
	283	const mpw /av/, const mpw /avl/,
	284	size_t /n/);
	285
	286	/----- Unsigned arithmetic -----------------------------------------------/
	287
7c13f461	288	/* --- @mpx_2c@ --- *
	289	*
	290	* Arguments: @mpw dv, dvl@ = destination vector
	291	* @const mpw v, vl@ = source vector
	292	*
	293	* Returns: ---
	294	*
	295	* Use: Calculates the two's complement of @v@.
	296	*/
	297
	298	extern void mpx_2c(mpw /dv/, mpw /dvl/,
	299	const mpw /v/, const mpw /vl/);
	300
d03ab969	301	/* --- @mpx_ucmp@ --- *
	302	*
	303	* Arguments: @const mpw av, avl@ = first argument vector base and limit
	304	* @const mpw bv, bvl@ = second argument vector base and limit
	305	*
	306	* Returns: Less than, equal to, or greater than zero depending on
	307	* whether @a@ is less than, equal to or greater than @b@,
	308	* respectively.
	309	*
	310	* Use: Performs an unsigned integer comparison.
	311	*/
	312
	313	#define MPX_UCMP(av, avl, op, dv, dvl) \
	314	(mpx_ucmp((av), (avl), (dv), (dvl)) op 0)
	315
	316	extern int mpx_ucmp(const mpw /av/, const mpw /avl/,
	317	const mpw /bv/, const mpw /bvl/);
	318
	319	/* --- @mpx_uadd@ --- *
	320	*
	321	* Arguments: @mpw dv, dvl@ = destination vector base and limit
	322	* @const mpw av, avl@ = first addend vector base and limit
	323	* @const mpw bv, bvl@ = second addend vector base and limit
	324	*
	325	* Returns: ---
	326	*
	327	* Use: Performs unsigned integer addition. If the result overflows
	328	* the destination vector, high-order bits are discarded. This
	329	* means that two's complement addition happens more or less for
	330	* free, although that's more a side-effect than anything else.
	331	* The result vector may be equal to either or both source
	332	* vectors, but may not otherwise overlap them.
	333	*/
	334
	335	extern void mpx_uadd(mpw /dv/, mpw /dvl/,
	336	const mpw /av/, const mpw /avl/,
	337	const mpw /bv/, const mpw /bvl/);
	338
3c9ede17	339	/* --- @MPX_UADDN@ --- *
	340	*
	341	* Arguments: @dv, dvl@ = source and destination vector base and limit
	342	* @n@ = other addend
	343	*
	344	* Use: Adds a small integer to a multiprecision number.
	345	*/
	346
	347	#define MPX_UADDN(dv, dvl, n) do { \
	348	mpw _ddv = (dv), _ddvl = (dvl); \
	349	mpw _c = (n); \
	350	\
	351	while (_c && _ddv < _ddvl) { \
	352	mpd _x = (mpd)*_ddv + (mpd)_c; \
	353	*_ddv++ = MPW(_x); \
	354	_c = _x >> MPW_BITS; \
	355	} \
	356	} while (0)
	357
d03ab969	358	/* --- @mpx_usub@ --- *
	359	*
	360	* Arguments: @mpw dv, dvl@ = destination vector base and limit
	361	* @const mpw av, avl@ = first argument vector base and limit
	362	* @const mpw bv, bvl@ = second argument vector base and limit
	363	*
	364	* Returns: ---
	365	*
	366	* Use: Performs unsigned integer subtraction. If the result
	367	* overflows the destination vector, high-order bits are
	368	* discarded. This means that two's complement subtraction
3c9ede17	369	* happens more or less for free, although that's more a side-
d03ab969	370	* effect than anything else. The result vector may be equal to
	371	* either or both source vectors, but may not otherwise overlap
	372	* them.
	373	*/
	374
	375	extern void mpx_usub(mpw /dv/, mpw /dvl/,
	376	const mpw /av/, const mpw /avl/,
	377	const mpw /bv/, const mpw /bvl/);
	378
3c9ede17	379	/* --- @MPX_USUBN@ --- *
	380	*
	381	* Arguments: @@dv, dvl@ = destination vector base and limit
	382	* @n@ = other addend
	383	*
	384	* Use: Subtracts a small integer from a multiprecision number.
	385	*/
	386
	387	#define MPX_USUBN(dv, dvl, n) do { \
	388	mpw _ddv = (dv), _ddvl = (dvl); \
	389	mpw _c = (n); \
	390	\
	391	while (_ddv < _ddvl) { \
	392	mpd _x = (mpd)*_ddv - (mpd)_c; \
	393	*_ddv++ = MPW(_x); \
	394	if (_x >> MPW_BITS) \
	395	_c = 1; \
	396	else \
	397	break; \
	398	} \
	399	} while (0)
	400
	401	/* --- @mpx_umul@ --- *
	402	*
	403	* Arguments: @mpw dv, dvl@ = destination vector base and limit
	404	* @const mpw av, avl@ = multiplicand vector base and limit
	405	* @const mpw bv, bvl@ = multiplier vector base and limit
	406	*
	407	* Returns: ---
	408	*
	409	* Use: Performs unsigned integer multiplication. If the result
	410	* overflows the desination vector, high-order bits are
	411	* discarded. The result vector may not overlap the argument
	412	* vectors in any way.
	413	*/
	414
	415	extern void mpx_umul(mpw /dv/, mpw /dvl/,
	416	const mpw /av/, const mpw /avl/,
	417	const mpw /bv/, const mpw /bvl/);
	418
d03ab969	419	/* --- @MPX_UMULN@ --- *
	420	*
	421	* Arguments: @dv, dvl@ = destination vector base and limit
	422	* @av, avl@ = multiplicand vector base and limit
	423	* @m@ = multiplier
	424	*
	425	* Use: Multiplies a multiprecision integer by a single-word value.
	426	* The destination and source may be equal. The destination
	427	* is completely cleared after use.
	428	*/
	429
	430	#define MPX_UMULN(dv, dvl, av, avl, m) do { \
	431	mpw _dv = (dv), _dvl = (dvl); \
	432	const mpw _av = (av), _avl = (avl); \
	433	mpw _c = 0; \
	434	mpd _m = (m); \
	435	\
	436	while (_av < _avl) { \
	437	mpd _x; \
	438	if (_dv >= _dvl) \
	439	break; \
3c9ede17	440	_x = (mpd)_m * (mpd)*_av++ + _c; \
d03ab969	441	*_dv++ = MPW(_x); \
	442	_c = _x >> MPW_BITS; \
	443	} \
	444	if (_dv < _dvl) { \
	445	*_dv++ = MPW(_c); \
	446	MPX_ZERO(_dv, _dvl); \
	447	} \
	448	} while (0)
	449
	450	/* --- @MPX_UMLAN@ --- *
	451	*
	452	* Arguments: @dv, dvl@ = destination/accumulator vector base and limit
	453	* @av, avl@ = multiplicand vector base and limit
	454	* @m@ = multiplier
	455	*
	456	* Use: Multiplies a multiprecision integer by a single-word value
	457	* and adds the result to an accumulator.
	458	*/
	459
	460	#define MPX_UMLAN(dv, dvl, av, avl, m) do { \
	461	mpw _dv = (dv), _dvl = (dvl); \
	462	const mpw _av = (av), _avl = (avl); \
7c13f461	463	mpw _cc = 0; \
d03ab969	464	mpd _m = (m); \
	465	\
	466	while (_av < _avl) { \
	467	mpd _x; \
	468	if (_dv >= _dvl) \
	469	break; \
7c13f461	470	_x = (mpd)_dv + (mpd)_m (mpd)*_av++ + _cc; \
d03ab969	471	*_dv++ = MPW(_x); \
7c13f461	472	_cc = _x >> MPW_BITS; \
d03ab969	473	} \
7c13f461	474	MPX_UADDN(_dv, _dvl, _cc); \
d03ab969	475	} while (0)
d03ab969	476
3c9ede17	477	/* --- @mpx_usqr@ --- *
d03ab969	478	*
d03ab969	479	* Arguments: @mpw dv, dvl@ = destination vector base and limit
3c9ede17	480	* @const mpw av, av@ = source vector base and limit
d03ab969	481	*
	482	* Returns: ---
	483	*
3c9ede17	484	* Use: Performs unsigned integer squaring. The result vector must
3c9ede17	485	* not overlap the source vector in any way.
d03ab969	486	*/
d03ab969	487
3c9ede17	488	extern void mpx_usqr(mpw /dv/, mpw /dvl/,
3c9ede17	489	const mpw /av/, const mpw /avl/);
d03ab969	490
	491	/* --- @mpx_udiv@ --- *
	492	*
	493	* Arguments: @mpw qv, qvl@ = quotient vector base and limit
	494	* @mpw rv, rvl@ = dividend/remainder vector base and limit
	495	* @const mpw dv, dvl@ = divisor vector base and limit
3c9ede17	496	* @mpw sv, svl@ = scratch workspace
d03ab969	497	*
	498	* Returns: ---
	499	*
	500	* Use: Performs unsigned integer division. If the result overflows
	501	* the quotient vector, high-order bits are discarded. (Clearly
	502	* the remainder vector can't overflow.) The various vectors
	503	* may not overlap in any way. Yes, I know it's a bit odd
	504	* requiring the dividend to be in the result position but it
3c9ede17	505	* does make some sense really. The remainder must have
3c9ede17	506	* headroom for at least two extra words. The scratch space
7c13f461	507	* must be at least one word larger than the divisor.
d03ab969	508	*/
	509
	510	extern void mpx_udiv(mpw /qv/, mpw /qvl/, mpw /rv/, mpw /rvl/,
3c9ede17	511	const mpw /dv/, const mpw /dvl/,
3c9ede17	512	mpw /sv/, mpw /svl/);
d03ab969	513
	514	/----- That's all, folks -------------------------------------------------/
	515
	516	#ifdef __cplusplus
	517	}
	518	#endif
	519
	520	#endif