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Manual Pages  — Q_SIGNSHFT

NAME

Q_SIGNSHFT, Q_SSIGN, Q_CRAWMASK, Q_SRAWMASK, Q_GCRAW, Q_GCVAL, Q_SCVAL – fixed-point math functions which manipulate the control/sign data bits

CONTENTS

SYNOPSIS

#include <sys/qmath.h>

uint32_t
Q_SIGNSHFT(QTYPE q);

QTYPE
Q_SSIGN(QTYPE q, bool isneg);

ITYPE
Q_CRAWMASK(QTYPE q);

ITYPE
Q_SRAWMASK(QTYPE q);

ITYPE
Q_GCRAW(QTYPE q);

ITYPE
Q_GCVAL(QTYPE q);

QTYPE
Q_SCVAL(QTYPE q, ITYPE cv);

DESCRIPTION

Q_SIGNSHFT() gets the bit position of q, Ap, s sign bit relative to bit zero.

Q_SSIGN() sets the sign bit of q based on the boolean isneg.

Q_CRAWMASK() and Q_SRAWMASK() return q, Ns, -specific bit masks for q, Ap, s control bits and sign bit respectively.

Q_GCRAW() and Q_GCVAL() get the raw masked control bits and value of q, Ap, s control bits respectively.

Q_SCVAL() sets q, Ap, s control bits to the value cv.

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_SIGNSHFT() returns the sign bit's position as an integer.

Q_SSIGN() returns the value of q post change.

Q_CRAWMASK(), Q_SRAWMASK(), Q_GCRAW() and Q_GCVAL() return their respective values as integers of the same underlying ITYPE as q.

Q_SCVAL() returns the value of q post change.

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 <Mt lstewart@FreeBSD.org> and sponsored by Netflix, Inc.
Q_SIGNSHFT (3) July 8, 2018
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