LIBMP(3) BSD Library Functions Manual LIBMP(3)NAMElibmp — traditional BSD multiple precision integer arithmetic library
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)).
This interface is obsolete in favor of the crypto(3) BIGNUM library.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 compat‐
These routines perform arithmetic on integers of arbitrary precision
stored using the defined type MINT. Pointers to MINT are initialized
using mp_itom() or mp_xtom(), and must be recycled with mp_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 implemented:
MINT *mp_itom(short n);
MINT *mp_xtom(const char *s);
char *mp_mtox(const MINT *mp);
void mp_mfree(MINT *mp);
mp_itom() returns an MINT with the value of n. mp_xtom() returns
an MINT with the value of s, which is treated to be in hexadecimal.
The return values from mp_itom() and mp_xtom() must be released
with mp_mfree() when they are no longer needed. mp_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
void mp_madd(const MINT *mp1, const MINT *mp2, MINT *rmp);
void mp_msub(const MINT *mp1, const MINT *mp2, MINT *rmp);
void mp_mult(const MINT *mp1, const MINT *mp2, MINT *rmp);
mp_madd(), mp_msub(), and mp_mult() store the sum, difference, or
product, respectively, of mp1 and mp2 in rmp.
void mp_mdiv(const MINT *nmp, const MINT *dmp, MINT *qmp, MINT *rmp);
void mp_sdiv(const MINT *nmp, short d, MINT *qmp, short *ro);
mp_mdiv() computes the quotient and remainder of nmp and dmp and
stores the result in qmp and rmp, respectively. mp_sdiv() is simi‐
lar to mp_mdiv() except the divisor (dmp or d) and remainder (rmp
or ro) are ordinary integers.
void mp_pow(const MINT *bmp, const MINT *emp, const MINT *mmp, MINT
void mp_rpow(const MINT *bmp, short e, MINT *rmp);
mp_rpow() computes the result of bmp raised to the empth power and
reduced modulo mmp; the result is stored in rmp. mp_pow() computes
the result of bmp raised to the eth power and stores the result in
void mp_min(MINT *mp);
void mp_mout(const MINT *mp);
mp_min() reads a line from standard input, tries to interpret it as
a decimal number, and if successful, stores the result in mp.
mp_mout() prints the value, in decimal, of mp to standard output
(without a trailing newline).
void mp_gcd(const MINT *mp1, const MINT *mp2, MINT *rmp);
mp_gcd() computes the greatest common divisor of mp1 and mp2 and
stores the result in rmp.
int mp_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 mp_move(const MINT *smp, MINT *tmp);
mp_move() copies the value of smp to tmp (both values must be ini‐
void mp_msqrt(const MINT *nmp, MINT *xmp, MINT *rmp);
mp_msqrt() computes the square root and remainder of nmp and stores
them in xmp and rmp, respectively.
This version of libmp is implemented in terms of the crypto(3) BIGNUM
Running out of memory or illegal operations result in error messages on
standard error and a call to abort(3).
SEE ALSOabort(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 appeared in
Errors are reported via output to standard error and abnormal program
termination instead of via return values. The application cannot control
It is not clear whether the string returned by mp_mtox() may be written
to by the caller. This implementation allows it, but others may not.
Ideally, mp_mtox() would take a pointer to a buffer to fill in.
It is not clear whether using the same variable as both source and desti‐
nation in a single invocation is permitted. Some of the calls in this
implementation allow this, while others do not.
BSD September 7, 1989 BSD