Piotr Caban : msvcrt: Import cbrtf implementation from musl.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 09bcc133f0d2ddfd0b88d966fdaab2a741c9e3ff
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=09bcc133f0d2ddfd0b88d966fdaab2a741c9e3ff

Author: Piotr Caban <piotr at codeweavers.com>
Date:   Mon May 17 15:37:51 2021 +0200

msvcrt: Import cbrtf implementation from musl.

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

---

 configure             |  1 -
 configure.ac          |  1 -
 dlls/msvcrt/math.c    | 30 +++++++++++++++++++++++++++++-
 dlls/msvcrt/unixlib.c | 13 -------------
 dlls/msvcrt/unixlib.h |  1 -
 include/config.h.in   |  3 ---
 6 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/configure b/configure
index 886a463a92a..3cbe4bed79e 100755
--- a/configure
+++ b/configure
@@ -19623,7 +19623,6 @@ for ac_func in \
 	atanh \
 	atanhf \
 	cbrt \
-	cbrtf \
 	erf \
 	erfc \
 	erfcf \
diff --git a/configure.ac b/configure.ac
index 2b126a7c579..845b076a8ba 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2663,7 +2663,6 @@ AC_CHECK_FUNCS(\
 	atanh \
 	atanhf \
 	cbrt \
-	cbrtf \
 	erf \
 	erfc \
 	erfcf \
diff --git a/dlls/msvcrt/math.c b/dlls/msvcrt/math.c
index 41096ded6e4..db59f5a0787 100644
--- a/dlls/msvcrt/math.c
+++ b/dlls/msvcrt/math.c
@@ -4505,10 +4505,38 @@ double CDECL cbrt(double x)
 
 /*********************************************************************
  *      cbrtf (MSVCR120.@)
+ *
+ * Copied from musl: src/math/cbrtf.c
  */
 float CDECL cbrtf(float x)
 {
-    return unix_funcs->cbrtf( x );
+    static const unsigned B1 = 709958130, B2 = 642849266;
+
+    double r,T;
+    union {float f; UINT32 i;} u = {x};
+    UINT32 hx = u.i & 0x7fffffff;
+
+    if (hx >= 0x7f800000)
+        return x + x;
+
+    if (hx < 0x00800000) {  /* zero or subnormal? */
+        if (hx == 0)
+            return x;
+        u.f = x * 0x1p24f;
+        hx = u.i & 0x7fffffff;
+        hx = hx / 3 + B2;
+    } else
+        hx = hx / 3 + B1;
+    u.i &= 0x80000000;
+    u.i |= hx;
+
+    T = u.f;
+    r = T * T * T;
+    T = T * (x + x + r) / (x + r + r);
+
+    r = T * T * T;
+    T = T * (x + x + r) / (x + r + r);
+    return T;
 }
 
 /*********************************************************************
diff --git a/dlls/msvcrt/unixlib.c b/dlls/msvcrt/unixlib.c
index a5b59bc2cf3..56c70742133 100644
--- a/dlls/msvcrt/unixlib.c
+++ b/dlls/msvcrt/unixlib.c
@@ -133,18 +133,6 @@ static double CDECL unix_cbrt(double x)
 #endif
 }
 
-/*********************************************************************
- *      cbrtf
- */
-static float CDECL unix_cbrtf(float x)
-{
-#ifdef HAVE_CBRTF
-    return cbrtf(x);
-#else
-    return unix_cbrt(x);
-#endif
-}
-
 /*********************************************************************
  *      ceil
  */
@@ -738,7 +726,6 @@ static const struct unix_funcs funcs =
     unix_atanh,
     unix_atanhf,
     unix_cbrt,
-    unix_cbrtf,
     unix_ceil,
     unix_ceilf,
     unix_cos,
diff --git a/dlls/msvcrt/unixlib.h b/dlls/msvcrt/unixlib.h
index 3d41967a2a0..c3b2b500c6d 100644
--- a/dlls/msvcrt/unixlib.h
+++ b/dlls/msvcrt/unixlib.h
@@ -30,7 +30,6 @@ struct unix_funcs
     double          (CDECL *atanh)(double x);
     float           (CDECL *atanhf)(float x);
     double          (CDECL *cbrt)(double x);
-    float           (CDECL *cbrtf)(float x);
     double          (CDECL *ceil)(double x);
     float           (CDECL *ceilf)(float x);
     double          (CDECL *cos)(double x);
diff --git a/include/config.h.in b/include/config.h.in
index 56f3bc90003..34103b765fc 100644
--- a/include/config.h.in
+++ b/include/config.h.in
@@ -70,9 +70,6 @@
 /* Define to 1 if you have the `cbrt' function. */
 #undef HAVE_CBRT
 
-/* Define to 1 if you have the `cbrtf' function. */
-#undef HAVE_CBRTF
-
 /* Define to 1 if you have the `clock_gettime' function. */
 #undef HAVE_CLOCK_GETTIME