Piotr Caban : msvcrt: Import floor implementation from musl.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 29c07324c19bbdaf5255b230cca5e0db5c5796c4
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=29c07324c19bbdaf5255b230cca5e0db5c5796c4

Author: Piotr Caban <piotr at codeweavers.com>
Date:   Mon May 17 15:38:15 2021 +0200

msvcrt: Import floor implementation from musl.

The implementation is based on floorf.

Signed-off-by: Piotr Caban <piotr at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/msvcrt/math.c    | 23 ++++++++++++++++++++++-
 dlls/msvcrt/unixlib.c |  9 ---------
 dlls/msvcrt/unixlib.h |  1 -
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/dlls/msvcrt/math.c b/dlls/msvcrt/math.c
index d85b43c7d7f..5682b00bb66 100644
--- a/dlls/msvcrt/math.c
+++ b/dlls/msvcrt/math.c
@@ -1811,10 +1811,31 @@ double CDECL ceil( double x )
 
 /*********************************************************************
  *		floor (MSVCRT.@)
+ *
+ * Based on musl: src/math/floorf.c
  */
 double CDECL floor( double x )
 {
-  return unix_funcs->floor(x);
+    union {double f; UINT64 i;} u = {x};
+    int e = (int)(u.i >> 52 & 0x7ff) - 0x3ff;
+    UINT64 m;
+
+    if (e >= 52)
+        return x;
+    if (e >= 0) {
+        m = 0x000fffffffffffffULL >> e;
+        if ((u.i & m) == 0)
+            return x;
+        if (u.i >> 63)
+            u.i += m;
+        u.i &= ~m;
+    } else {
+        if (u.i >> 63 == 0)
+            return 0;
+        else if (u.i << 1)
+            return -1;
+    }
+    return u.f;
 }
 
 /*********************************************************************
diff --git a/dlls/msvcrt/unixlib.c b/dlls/msvcrt/unixlib.c
index 9cdcd14e986..83a1e5386c1 100644
--- a/dlls/msvcrt/unixlib.c
+++ b/dlls/msvcrt/unixlib.c
@@ -273,14 +273,6 @@ static float CDECL unix_expm1f(float x)
 #endif
 }
 
-/*********************************************************************
- *      floor
- */
-static double CDECL unix_floor( double x )
-{
-    return floor( x );
-}
-
 /*********************************************************************
  *      fma
  */
@@ -703,7 +695,6 @@ static const struct unix_funcs funcs =
     unix_exp2f,
     unix_expm1,
     unix_expm1f,
-    unix_floor,
     unix_fma,
     unix_fmaf,
     unix_fmod,
diff --git a/dlls/msvcrt/unixlib.h b/dlls/msvcrt/unixlib.h
index 47af0e464cd..a86e2d34852 100644
--- a/dlls/msvcrt/unixlib.h
+++ b/dlls/msvcrt/unixlib.h
@@ -43,7 +43,6 @@ struct unix_funcs
     float           (CDECL *exp2f)(float x);
     double          (CDECL *expm1)(double x);
     float           (CDECL *expm1f)(float x);
-    double          (CDECL *floor)(double x);
     double          (CDECL *fma)(double x, double y, double z);
     float           (CDECL *fmaf)(float x, float y, float z);
     double          (CDECL *fmod)(double x, double y);