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 <
[email protected]> and sponsored by Netflix, Inc.
FreeBSD 14.1-RELEASE-p8 July 8, 2018 FreeBSD 14.1-RELEASE-p8