From 854a3cab4c136d3e2292bcd9c42c530e56cef7e9 Mon Sep 17 00:00:00 2001
From: Piotr Caban <piotr@codeweavers.com>
Date: Fri, 14 May 2021 16:11:48 +0200
Subject: [PATCH] msvcrt: Import neabyint implementation from musl.

Signed-off-by: Piotr Caban <piotr@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
---
 configure             |  1 -
 configure.ac          |  1 -
 dlls/msvcrt/math.c    | 13 +++++++++++--
 dlls/msvcrt/unixlib.c | 13 -------------
 dlls/msvcrt/unixlib.h |  1 -
 include/config.h.in   |  3 ---
 6 files changed, 11 insertions(+), 21 deletions(-)

diff --git a/configure b/configure
index 91f0c586c60..525d585130f 100755
--- a/configure
+++ b/configure
@@ -19640,7 +19640,6 @@ for ac_func in \
 	log1pf \
 	log2 \
 	log2f \
-	nearbyint \
 	nexttoward \
 	nexttowardf \
 	remainder \
diff --git a/configure.ac b/configure.ac
index df1025aeb98..2e8ff20aeef 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2680,7 +2680,6 @@ AC_CHECK_FUNCS(\
 	log1pf \
 	log2 \
 	log2f \
-	nearbyint \
 	nexttoward \
 	nexttowardf \
 	remainder \
diff --git a/dlls/msvcrt/math.c b/dlls/msvcrt/math.c
index 7fe7b9d172b..2bc51213a07 100644
--- a/dlls/msvcrt/math.c
+++ b/dlls/msvcrt/math.c
@@ -3418,10 +3418,19 @@ double CDECL _yn(int n, double x)
 
 /*********************************************************************
  *		_nearbyint (MSVCR120.@)
+ *
+ * Based on musl: src/math/nearbyteint.c
  */
-double CDECL nearbyint(double num)
+double CDECL nearbyint(double x)
 {
-    return unix_funcs->nearbyint( num );
+    fenv_t env;
+
+    fegetenv(&env);
+    _control87(_MCW_EM, _MCW_EM);
+    x = rint(x);
+    feclearexcept(FE_INEXACT);
+    feupdateenv(&env);
+    return x;
 }
 
 /*********************************************************************
diff --git a/dlls/msvcrt/unixlib.c b/dlls/msvcrt/unixlib.c
index a0892e98d97..376bdb5c1c7 100644
--- a/dlls/msvcrt/unixlib.c
+++ b/dlls/msvcrt/unixlib.c
@@ -547,18 +547,6 @@ static float CDECL unix_modff( float x, float *iptr )
     return modff( x, iptr );
 }
 
-/*********************************************************************
- *      nearbyint
- */
-static double CDECL unix_nearbyint(double num)
-{
-#ifdef HAVE_NEARBYINT
-    return nearbyint(num);
-#else
-    return num >= 0 ? floor(num + 0.5) : ceil(num - 0.5);
-#endif
-}
-
 /*********************************************************************
  *      nextafter
  */
@@ -834,7 +822,6 @@ static const struct unix_funcs funcs =
     unix_logbf,
     unix_modf,
     unix_modff,
-    unix_nearbyint,
     unix_nextafter,
     unix_nextafterf,
     unix_nexttoward,
diff --git a/dlls/msvcrt/unixlib.h b/dlls/msvcrt/unixlib.h
index d8b5e6b3f24..ecdbdf0cca1 100644
--- a/dlls/msvcrt/unixlib.h
+++ b/dlls/msvcrt/unixlib.h
@@ -72,7 +72,6 @@ struct unix_funcs
     float           (CDECL *logbf)(float x);
     double          (CDECL *modf)(double x, double *iptr);
     float           (CDECL *modff)(float x, float *iptr);
-    double          (CDECL *nearbyint)(double num);
     double          (CDECL *nextafter)(double x, double y);
     float           (CDECL *nextafterf)(float x, float y);
     double          (CDECL *nexttoward)(double x, double y);
diff --git a/include/config.h.in b/include/config.h.in
index 896d44cd71e..a638c0382c9 100644
--- a/include/config.h.in
+++ b/include/config.h.in
@@ -501,9 +501,6 @@
 /* Define if MTLDevice protocol has registryID property. */
 #undef HAVE_MTLDEVICE_REGISTRYID
 
-/* Define to 1 if you have the `nearbyint' function. */
-#undef HAVE_NEARBYINT
-
 /* Define to 1 if you have the <netdb.h> header file. */
 #undef HAVE_NETDB_H