libmp(3)

NAME

libmp - traditional BSD multiple precision integer arith

metic library

SYNOPSIS

#include <mp.h>
Function  prototypes are given in the main body of the text.
Applications using this interface must be linked  with  -lmp
(this library)
and -lcrypto (crypto(3)).

DESCRIPTION

This interface is obsolete in favor of the crypto(3) BIGNUM

library.

libmp is the traditional BSD multiple precision integer

arithmetic
library. It has a number of problems, and is unsuitable for

use in any
programs where reliability is a concern. It is provided

here for compatibility only.

These routines perform arithmetic on integers of arbitrary

precision
stored using the defined type MINT. Pointers to MINT are

initialized
using itom() or xtom(), and must be recycled with mfree()

when they are
no longer needed. Routines which store a result in one of

their arguments expect that the latter has also been initialized prior

to being
passed to it. The following routines are defined and imple

mented:

MINT *itom(short n);

MINT *xtom(const char *s);

char *mtox(const MINT *mp);

void mfree(MINT *mp);

itom() returns an MINT with the value of n. xtom()

returns an MINT
with the value of s, which is treated to be in hex

adecimal. The
return values from itom() and xtom() must be released

with mfree()
when they are no longer needed. mtox() returns a

null-terminated
hexadecimal string having the value of mp; its return

value must be
released with free() (free(3)) when it is no longer

needed.

void madd(const MINT *mp1, const MINT *mp2, MINT *rmp);

void msub(const MINT *mp1, const MINT *mp2, MINT *rmp);

void mult(const MINT *mp1, const MINT *mp2, MINT *rmp);

madd(), msub(), and mult() store the sum, difference,

or product,
respectively, of mp1 and mp2 in rmp.

void mdiv(const MINT *nmp, const MINT *dmp, MINT *qmp, MINT

*rmp);

void sdiv(const MINT *nmp, short d, MINT *qmp, short *ro);

mdiv() computes the quotient and remainder of nmp and

dmp and
stores the result in qmp and rmp, respectively.

sdiv() is similar
to mdiv() except the divisor (dmp or d) and remainder

(rmp or ro)
are ordinary integers.

void pow(const MINT *bmp, const MINT *emp, const MINT *mmp,

MINT *rmp);

void rpow(const MINT *bmp, short e, MINT *rmp);

rpow() computes the result of bmp raised to the empth

power and
reduced modulo mmp; the result is stored in rmp.

pow() computes
the result of bmp raised to the eth power and stores

the result in
rmp.

void min(MINT *mp);

void mout(const MINT *mp);

min() reads a line from standard input, tries to in

terpret it as a
decimal number, and if successful, stores the result

in mp. mout()
prints the value, in decimal, of mp to standard output

(without a
trailing newline).

void gcd(const MINT *mp1, const MINT *mp2, MINT *rmp);

gcd() computes the greatest common divisor of mp1 and

mp2 and
stores the result in rmp.

int mcmp(const MINT *mp1, const MINT *mp2);

mcmp compares the values of mp1 and mp2 and returns 0

if the two
values are equal, a value greater than 0 if mp1 is

greater than
mp2, and a value less than 0 if mp2 is greater than

mp1.

void move(const MINT *smp, MINT *tmp);

move() copies the value of smp to tmp (both values

must be initialized).

void msqrt(const MINT *nmp, MINT *xmp, MINT *rmp);

msqrt() computes the square root and remainder of nmp

and stores
them in xmp and rmp, respectively.

IMPLEMENTATION NOTES

This version of libmp is implemented in terms of the cryp

to(3) BIGNUM
library.

DIAGNOSTICS

Running out of memory or illegal operations result in error

messages on
standard error and a call to abort(3).

SEE ALSO

abort(3), bn(3), crypto(3), free(3), malloc(3), math(3)

HISTORY

A libmp library appeared in 4.3BSD. FreeBSD 2.2 shipped

with a libmp
implemented in terms of libgmp. This implementation ap

peared in
FreeBSD 5.0.

BUGS

The pow() routine exists in both libmp and libm with incom

patible semantics.

Errors are reported via output to standard error and abnor

mal program
termination instead of via return values. The application

cannot control
this behavior.

It is not clear whether the string returned by mtox() may be

written to
by the caller. This implementation allows it, but others

may not. Ideally, mtox() would take a pointer to a buffer to fill in.

It is not clear whether using the same variable as both

source and destination in a single invocation is permitted. Some of the

calls in this
implementation allow this, while others do not.

BSD September 7, 1989

BSD