Q_QADDQ(3)             FreeBSD Library Functions Manual             Q_QADDQ(3)

NAME
     Q_QADDQ, Q_QDIVQ, Q_QMULQ, Q_QSUBQ, Q_NORMPREC, Q_QMAXQ, Q_QMINQ,
     Q_QCLONEQ, Q_CPYVALQ - fixed-point math functions which operate on two Q
     numbers

SYNOPSIS
     #include <sys/qmath.h>

     int
     Q_QADDQ(QTYPE *a, QTYPE b);

     int
     Q_QDIVQ(QTYPE *a, QTYPE b);

     int
     Q_QMULQ(QTYPE *a, QTYPE b);

     int
     Q_QSUBQ(QTYPE *a, QTYPE b);

     int
     Q_NORMPREC(QTYPE *a, QTYPE *b);

     QTYPE
     Q_QMAXQ(QTYPE a, QTYPE b);

     QTYPE
     Q_QMINQ(QTYPE a, QTYPE b);

     int
     Q_QCLONEQ(QTYPE *l, QTYPE r);

     int
     Q_QCPYVALQ(QTYPE *l, QTYPE r);

DESCRIPTION
     The Q_QADDQ(), Q_QDIVQ(), Q_QMULQ(), and Q_QSUBQ() functions add, divide,
     multiply or subtract b to/by/from a respectively, storing the result in
     a.  Both arguments must be initialized with the same fractional radix
     point.

     The Q_NORMPREC() function attempts to normalise the precision of a and b
     if they differ.  The greater of the two precisions is preferred if
     possible, unless that would truncate integer component data for the other
     operand, in which case the highest precision that preserves the integer
     component of both a and b is selected.

     The Q_QMAXQ() and Q_QMINQ() functions return the larger or smaller of a
     and b respectively.

     The Q_QCLONEQ() and Q_QCPYVALQ() functions attempt to store identical or
     representational copies of r, in l respectively.  An identical Q number
     produced by cloning copies the control bits as well as the verbatim
     integer/fractional bits.  A representational copy only copies the values
     of r's integer and fractional bits, representing them in the bits
     available per l's Q format.

     All of those functions operate on the following data types: s8q_t, u8q_t,
     s16q_t, u16q_t, s32q_t, u32q_t, s64q_t, and u64q_t, which are referred to
     generically as QTYPE.

     For more details, see qmath(3).

RETURN VALUES
     The Q_QADDQ(), Q_QDIVQ(), Q_QMULQ(), Q_QSUBQ() Q_NORMPREC(), Q_QCLONEQ()
     and Q_QCPYVALQ() functions return 0 on success, or an errno on failure.
     EINVAL is returned for divide-by-zero.  EOVERFLOW and ERANGE are returned
     for overflow and underflow respectively.  ERANGE is also returned when
     the precision of arguments does not match.

     The Q_QMAXQ() and Q_QMINQ() functions return the numerically larger or
     smaller of their two inputs respectively.

SEE ALSO
     errno(2), qmath(3), stdint(7)

HISTORY
     The qmath(3) functions first appeared in FreeBSD 13.0.

AUTHORS
     The qmath(3) functions and this manual page were written by Lawrence
     Stewart <lstewart@FreeBSD.org> and sponsored by Netflix, Inc.

FreeBSD 13.1-RELEASE-p6          July 8, 2018          FreeBSD 13.1-RELEASE-p6