135 lines
3.1 KiB
Groff
135 lines
3.1 KiB
Groff
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.\"
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.\" Copyright (c) 2018 Netflix, Inc.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions, and the following disclaimer,
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.\" without modification, immediately at the beginning of the file.
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.\" 2. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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.\" ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 8, 2018
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.Dt Q_QADDI 3
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.Os
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.Sh NAME
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.Nm Q_QADDI ,
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.Nm Q_QDIVI ,
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.Nm Q_QMULI ,
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.Nm Q_QSUBI ,
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.Nm Q_QFRACI ,
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.Nm Q_QCPYVALI
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.Nd fixed-point math functions which apply integers to a Q number
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.Sh SYNOPSIS
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.In sys/qmath.h
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.Ft int
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.Fn Q_QADDI "QTYPE *a" "ITYPE b"
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.Ft int
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.Fn Q_QDIVI "QTYPE *a" "ITYPE b"
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.Ft int
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.Fn Q_QMULI "QTYPE *a" "ITYPE b"
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.Ft int
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.Fn Q_QSUBI "QTYPE *a" "ITYPE b"
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.Ft int
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.Fn Q_QFRACI "QTYPE *q" "ITYPE n" "ITYPE d"
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.Ft int
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.Fn Q_QCPYVALI "QTYPE *q" "ITYPE i"
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.Sh DESCRIPTION
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The
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.Fn Q_QADDI ,
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.Fn Q_QDIVI ,
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.Fn Q_QMULI
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and
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.Fn Q_QSUBI
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functions add, divide, multiply or subtract
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.Fa b
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to/by/from
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.Fa a
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respectively, storing the result in
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.Fa a .
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.Pp
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The
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.Fn Q_QFRACI
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function computes the fraction
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.Fa n
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divided by
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.Fa d
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and stores the fixed-point result in
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.Fa q .
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.Pp
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The
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.Fn Q_QCPYVALI
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function overwrites
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.Fa q Ap s
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integer and fractional bits with the Q representation of integer value
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.Fa i .
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.Pp
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All of those functions operate on
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the following data types:
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.Vt s8q_t ,
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.Vt u8q_t ,
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.Vt s16q_t ,
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.Vt u16q_t ,
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.Vt s32q_t ,
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.Vt u32q_t ,
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.Vt s64q_t ,
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and
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.Vt u64q_t ,
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which are referred to generically as
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.Fa QTYPE .
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The
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.Fa ITYPE
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refers to the
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.Xr stdint 7
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integer types.
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.Pp
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For more details, see
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.Xr qmath 3 .
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.Sh RETURN VALUES
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.Fn Q_QADDI ,
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.Fn Q_QDIVI ,
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.Fn Q_QMULI ,
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.Fn Q_QSUBI ,
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.Fn Q_QFRACI
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and
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.Fn Q_QCPYVALI
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functions return 0 on success, or an errno on failure.
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.Er EINVAL
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is returned for divide-by-zero.
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.Er EOVERFLOW
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and
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.Er ERANGE
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are returned for overflow and underflow respectively.
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.Sh SEE ALSO
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.Xr errno 2 ,
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.Xr qmath 3 ,
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.Xr stdint 7
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.Sh HISTORY
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The
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.Xr qmath 3
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functions first appeared in
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.Fx 13.0 .
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.Sh AUTHORS
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.An -nosplit
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The
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.Xr qmath 3
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functions and this manual page were written by
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.An Lawrence Stewart Aq Mt lstewart@FreeBSD.org
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and sponsored by Netflix, Inc.
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