NAME
Q_QADDI, Q_QDIVI,
Q_QMULI, Q_QSUBI,
Q_QFRACI, Q_QCPYVALI
— fixed-point math functions
which apply integers to a Q number
SYNOPSIS
#include
<sys/qmath.h>
int
Q_QADDI(QTYPE
*a, ITYPE b);
int
Q_QDIVI(QTYPE
*a, ITYPE b);
int
Q_QMULI(QTYPE
*a, ITYPE b);
int
Q_QSUBI(QTYPE
*a, ITYPE b);
int
Q_QFRACI(QTYPE
*q, ITYPE n,
ITYPE d);
int
Q_QCPYVALI(QTYPE
*q, ITYPE i);
DESCRIPTION
TheQ_QADDI(),
Q_QDIVI(),
Q_QMULI()
and
Q_QSUBI()
functions add, divide, multiply or subtract b to/by/from
a respectively, storing the result in
a.
The
Q_QFRACI()
function computes the fraction n divided by
d and stores the fixed-point result in
q.
The
Q_QCPYVALI()
function overwrites q's integer and fractional bits
with the Q representation of integer value i.
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. The ITYPE refers to the stdint(7) integer types.
For more details, see qmath(3).
RETURN VALUES
Q_QADDI(),
Q_QDIVI(), Q_QMULI(),
Q_QSUBI(), Q_QFRACI() and
Q_QCPYVALI() 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.
SEE ALSO
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.