freebsd-dev/lib/msun/man/sincos.3
Michal Meloun e1b98d0774 Implement sincos, sincosf, and sincosl.
The primary benefit of these functions is that argument
reduction is done once instead of twice in independent
calls to sin() and cos().

* lib/msun/Makefile:
  . Add s_sincos[fl].c to the build.
  . Add sincos.3 documentation.
  . Add appropriate MLINKS.

* lib/msun/Symbol.map:
  . Expose sincos[fl] symbols in dynamic libm.so.

* lib/msun/man/sincos.3:
  . Documentation for sincos[fl].

* lib/msun/src/k_sincos.h:
  . Kernel for sincos() function.  This merges the individual kernels
    for sin() and cos().  The merger offered an opportunity to re-arrange
    the individual kernels for better performance.

* lib/msun/src/k_sincosf.h:
   . Kernel for sincosf() function.  This merges the individual kernels
     for sinf() and cosf(). The merger offered an opportunity to re-arrange
     the individual kernels for better performance.

* lib/msun/src/k_sincosl.h:
   . Kernel for sincosl() function.  This merges the individual kernels
     for sinl() and cosl(). The merger offered an opportunity to re-arrange
     the individual kernels for better performance.

* lib/msun/src/math.h:
  . Add prototytpes for sincos[fl]().

* lib/msun/src/math_private.h:
  . Add RETURNV macros.  This is needed to reset fpsetprec on I386
    hardware for a function with type void.

* lib/msun/src/s_sincos.c:
  . Implementation of sincos() where sin() and cos() were merged into
    one routine and possibly re-arranged for better performance.

* lib/msun/src/s_sincosf.c:
  . Implementation of sincosf() where sinf() and cosf() were merged into
    one routine and possibly re-arranged for better performance.

* lib/msun/src/s_sincosl.c:
  . Implementation of sincosl() where sinl() and cosl() were merged into
    one routine and possibly re-arranged for better performance.

PR:		215977, 218300
Submitted by:	Steven G. Kargl <sgk@troutmask.apl.washington.edu>
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D10765
2017-05-28 06:13:38 +00:00

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.\" Copyright (c) 2011 Steven G. Kargl.
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.Dd March 12, 2011
.Dt SINCOS 3
.Os
.Sh NAME
.Nm sincos ,
.Nm sincosf ,
.Nm sincosl
.Nd sine and cosine functions
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft void
.Fn sincos "double x" "double *s" "double *c"
.Ft void
.Fn sincosf "float x" "float *s" "float *c"
.Ft void
.Fn sincosl "long double x" "long double *s" "long double *c"
.Sh DESCRIPTION
The
.Fn sincos ,
.Fn sincosf ,
and
.Fn sincosl
functions compute the sine and cosine of
.Fa x .
Using these functions allows argument reduction to occur only
once instead of twice with individual invocations of
.Fn sin
and
.Fn cos .
Like
.Fn sin
and
.Fn cos ,
a large magnitude argument may yield a result with little
or no significance.
.Sh RETURN VALUES
Upon returning from
.Fn sincos ,
.Fn sincosf ,
and
.Fn sincosl ,
the memory pointed to by
.Ar "*s"
and
.Ar "*c"
are assigned the values of sine and cosine, respectively.
.Sh SEE ALSO
.Xr cos 3 ,
.Xr sin 3 ,
.Sh HISTORY
These functions were added to
.Fx 9.0
to aid in writing various complex function contained in
.St -isoC-99 .