[freetype2] master 84eebf4: Use MS VC++'s _BitScanReverse to calculate MSB (patch #9636).

[Werner LEMBERG]

branch: master
commit 84eebf48021ab76c1c628bb7451b712f701e4518
Author: Arkady Shapkin <address@hidden>
Commit: Werner Lemberg <address@hidden>

    Use MS VC++'s _BitScanReverse to calculate MSB (patch #9636).
    
    * include/freetype/internal/ftcalc.h (FT_MSB) [_MSC_VER]: Implement
    it.
---
 ChangeLog                          |  7 +++++++
 include/freetype/internal/ftcalc.h | 26 +++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 004c96f..4bd8e5e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2018-05-12  Arkady Shapkin  <address@hidden>
+
+       Use MS VC++'s _BitScanReverse to calculate MSB (patch #9636).
+
+       * include/freetype/internal/ftcalc.h (FT_MSB) [_MSC_VER]: Implement
+       it.
+
 2018-05-10  Alan Coopersmith  <address@hidden>
 
        Fix DLL compilation on Solaris.
diff --git a/include/freetype/internal/ftcalc.h 
b/include/freetype/internal/ftcalc.h
index 818a812..3f889e6 100644
--- a/include/freetype/internal/ftcalc.h
+++ b/include/freetype/internal/ftcalc.h
@@ -341,6 +341,7 @@ FT_BEGIN_HEADER
    */
 
 #ifndef  FT_CONFIG_OPTION_NO_ASSEMBLER
+
 #if defined( __GNUC__ )                                          && \
     ( __GNUC__ > 3 || ( __GNUC__ == 3 && __GNUC_MINOR__ >= 4 ) )
 
@@ -354,7 +355,30 @@ FT_BEGIN_HEADER
 
 #endif
 
-#endif /* __GNUC__ */
+
+#elif defined( _MSC_VER )
+
+#if FT_SIZEOF_INT == 4
+
+#include <intrin.h>
+
+  static inline FT_Int32
+  FT_MSB_i386( FT_UInt32  x )
+  {
+    unsigned long  where;
+
+
+    _BitScanReverse( &where, x );
+
+    return (FT_Int32)where;
+  }
+
+#define FT_MSB( x )  ( FT_MSB_i386( x ) )
+
+#endif
+
+#endif
+
 #endif /* !FT_CONFIG_OPTION_NO_ASSEMBLER */
 
 #ifndef FT_MSB