148 lines
3.3 KiB
Groff
148 lines
3.3 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_SIGNSHFT 3
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.Os
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.Sh NAME
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.Nm Q_SIGNSHFT ,
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.Nm Q_SSIGN ,
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.Nm Q_CRAWMASK ,
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.Nm Q_SRAWMASK ,
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.Nm Q_GCRAW ,
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.Nm Q_GCVAL ,
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.Nm Q_SCVAL
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.Nd fixed-point math functions which manipulate the control/sign data bits
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.Sh SYNOPSIS
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.In sys/qmath.h
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.Ft uint32_t
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.Fn Q_SIGNSHFT "QTYPE q"
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.Ft QTYPE
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.Fn Q_SSIGN "QTYPE q" "bool isneg"
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.Ft ITYPE
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.Fn Q_CRAWMASK "QTYPE q"
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.Ft ITYPE
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.Fn Q_SRAWMASK "QTYPE q"
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.Ft ITYPE
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.Fn Q_GCRAW "QTYPE q"
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.Ft ITYPE
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.Fn Q_GCVAL "QTYPE q"
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.Ft QTYPE
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.Fn Q_SCVAL "QTYPE q" "ITYPE cv"
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.Sh DESCRIPTION
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.Fn Q_SIGNSHFT
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gets the bit position of
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.Fa q Ap s
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sign bit relative to bit zero.
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.Pp
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.Fn Q_SSIGN
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sets the sign bit of
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.Fa q
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based on the boolean
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.Fa isneg .
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.Pp
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.Fn Q_CRAWMASK
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and
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.Fn Q_SRAWMASK
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return
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.Fa q Ns -specific
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bit masks for
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.Fa q Ap s
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control bits and sign bit respectively.
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.Pp
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.Fn Q_GCRAW
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and
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.Fn Q_GCVAL
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get the raw masked control bits and value of
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.Fa q Ap s
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control bits respectively.
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.Pp
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.Fn Q_SCVAL
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sets
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.Fa q Ap s
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control bits to the value
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.Fa cv .
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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_SIGNSHFT
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returns the sign bit's position as an integer.
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.Pp
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.Fn Q_SSIGN
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returns the value of
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.Fa q
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post change.
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.Pp
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.Fn Q_CRAWMASK ,
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.Fn Q_SRAWMASK ,
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.Fn Q_GCRAW
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and
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.Fn Q_GCVAL
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return their respective values as integers of the same underlying ITYPE as
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.Fa q .
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.Pp
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.Fn Q_SCVAL
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returns the value of
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.Fa q
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post change.
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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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