HardenedBSD/share/man/man3/Q_SIGNSHFT.3

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.Dd July 8, 2018
.Dt Q_SIGNSHFT 3
.Os
.Sh NAME
.Nm Q_SIGNSHFT ,
.Nm Q_SSIGN ,
.Nm Q_CRAWMASK ,
.Nm Q_SRAWMASK ,
.Nm Q_GCRAW ,
.Nm Q_GCVAL ,
.Nm Q_SCVAL
.Nd fixed-point math functions which manipulate the control/sign data bits
.Sh SYNOPSIS
.In sys/qmath.h
.Ft uint32_t
.Fn Q_SIGNSHFT "QTYPE q"
.Ft QTYPE
.Fn Q_SSIGN "QTYPE q" "bool isneg"
.Ft ITYPE
.Fn Q_CRAWMASK "QTYPE q"
.Ft ITYPE
.Fn Q_SRAWMASK "QTYPE q"
.Ft ITYPE
.Fn Q_GCRAW "QTYPE q"
.Ft ITYPE
.Fn Q_GCVAL "QTYPE q"
.Ft QTYPE
.Fn Q_SCVAL "QTYPE q" "ITYPE cv"
.Sh DESCRIPTION
.Fn Q_SIGNSHFT
gets the bit position of
.Fa q Ap s
sign bit relative to bit zero.
.Pp
.Fn Q_SSIGN
sets the sign bit of
.Fa q
based on the boolean
.Fa isneg .
.Pp
.Fn Q_CRAWMASK
and
.Fn Q_SRAWMASK
return
.Fa q Ns -specific
bit masks for
.Fa q Ap s
control bits and sign bit respectively.
.Pp
.Fn Q_GCRAW
and
.Fn Q_GCVAL
get the raw masked control bits and value of
.Fa q Ap s
control bits respectively.
.Pp
.Fn Q_SCVAL
sets
.Fa q Ap s
control bits to the value
.Fa cv .
.Pp
All of those functions operate on
the following data types:
.Vt s8q_t ,
.Vt u8q_t ,
.Vt s16q_t ,
.Vt u16q_t ,
.Vt s32q_t ,
.Vt u32q_t ,
.Vt s64q_t ,
and
.Vt u64q_t ,
which are referred to generically as
.Fa QTYPE .
The
.Fa ITYPE
refers to the
.Xr stdint 7
integer types.
.Pp
For more details, see
.Xr qmath 3 .
.Sh RETURN VALUES
.Fn Q_SIGNSHFT
returns the sign bit's position as an integer.
.Pp
.Fn Q_SSIGN
returns the value of
.Fa q
post change.
.Pp
.Fn Q_CRAWMASK ,
.Fn Q_SRAWMASK ,
.Fn Q_GCRAW
and
.Fn Q_GCVAL
return their respective values as integers of the same underlying ITYPE as
.Fa q .
.Pp
.Fn Q_SCVAL
returns the value of
.Fa q
post change.
.Sh SEE ALSO
.Xr errno 2 ,
.Xr qmath 3 ,
.Xr stdint 7
.Sh HISTORY
The
.Xr qmath 3
functions first appeared in
.Fx 13.0 .
.Sh AUTHORS
.An -nosplit
The
.Xr qmath 3
functions and this manual page were written by
.An Lawrence Stewart Aq Mt lstewart@FreeBSD.org
and sponsored by Netflix, Inc.