diff --git a/ChangeLog b/ChangeLog
index aacea17ad..f3d12c1e8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,33 @@
+2012-12-10  Alexei Podtelezhnikov  <apodtele@gmail.com>
+
+	[truetype] Scale F_dot_P down.
+
+	The dot product between freeVector and projVector or cosine of
+	the angle between these FT_F2Dot14 unit vectors used to be scaled up
+	by 4 and routinely occupied 32 bits in an FT_Long field F_dot_P.
+	This patch scales the value down by 2^14 instead, which simplifies 
+	its use throughout the bytecode interpreter.
+
+	This does not lead to the loss of precision because the lower bits
+	are unreliable anyway. Consider two unit vectors (1,0) and (.6,.8)
+	for which the true value of F_dot_P is .6 * 0x40000000 = 0x26666666.
+	These vectors are stored as (0x4000,0) and (0x2666,0x3333) after
+	rounding and F_dot_P is assigned 0x26660000. The lower bits were
+	already lost while rounding the unit vector components.
+
+	Besides code simplification, this change can lead to better
+	performance when FT_MulDiv with the scaled-down F_dot_P is less
+	likely to use the costly 64-bit path. We are not changing the type
+	of F_dot_P to FT_F2Dot14 at this point.  
+
+	* src/truetype/ttinterp.c (Compute_Funcs): Scale F_dot_P down by 14
+	bits and modify its use accordingly.
+	(Direct_Move, Direct_Move_Orig, Compute_Point_Displacement): Modify
+	the use of F_dot_P field.
+	* src/truetype/ttobjs.c (tt_size_run_fpgm): Change arbitrary
+	assignment of F_dot_P to its theoretical maximum in case we decide
+	to scale back its type later.
+
 2012-12-09  Johnson Y. Yan  <yinsen_yan@foxitsoftware.com>
 
 	[type1] Another fix for 2012-09-17 commit.
diff --git a/src/truetype/ttinterp.c b/src/truetype/ttinterp.c
index e1e09ee8e..736bda32c 100644
--- a/src/truetype/ttinterp.c
+++ b/src/truetype/ttinterp.c
@@ -1861,9 +1861,7 @@
       if ( !CUR.ignore_x_mode                                ||
            ( CUR.sph_tweak_flags & SPH_TWEAK_ALLOW_X_DMOVE ) )
 #endif /* TT_CONFIG_OPTION_SUBPIXEL_HINTING */
-      zone->cur[point].x += FT_MulDiv( distance,
-                                       v * 0x10000L,
-                                       CUR.F_dot_P );
+      zone->cur[point].x += FT_MulDiv( distance, v, CUR.F_dot_P );
 
       zone->tags[point] |= FT_CURVE_TAG_TOUCH_X;
     }
@@ -1872,9 +1870,7 @@
 
     if ( v != 0 )
     {
-      zone->cur[point].y += FT_MulDiv( distance,
-                                       v * 0x10000L,
-                                       CUR.F_dot_P );
+      zone->cur[point].y += FT_MulDiv( distance, v, CUR.F_dot_P );
 
       zone->tags[point] |= FT_CURVE_TAG_TOUCH_Y;
     }
@@ -1913,16 +1909,12 @@
     v = CUR.GS.freeVector.x;
 
     if ( v != 0 )
-      zone->org[point].x += FT_MulDiv( distance,
-                                       v * 0x10000L,
-                                       CUR.F_dot_P );
+      zone->org[point].x += FT_MulDiv( distance, v, CUR.F_dot_P );
 
     v = CUR.GS.freeVector.y;
 
     if ( v != 0 )
-      zone->org[point].y += FT_MulDiv( distance,
-                                       v * 0x10000L,
-                                       CUR.F_dot_P );
+      zone->org[point].y += FT_MulDiv( distance, v, CUR.F_dot_P );
   }
 
 
@@ -2646,12 +2638,13 @@
 #endif /* TT_CONFIG_OPTION_UNPATENTED_HINTING */
 
     if ( CUR.GS.freeVector.x == 0x4000 )
-      CUR.F_dot_P = CUR.GS.projVector.x * 0x10000L;
+      CUR.F_dot_P = CUR.GS.projVector.x;
     else if ( CUR.GS.freeVector.y == 0x4000 )
-      CUR.F_dot_P = CUR.GS.projVector.y * 0x10000L;
+      CUR.F_dot_P = CUR.GS.projVector.y;
     else
-      CUR.F_dot_P = (FT_Long)CUR.GS.projVector.x * CUR.GS.freeVector.x * 4 +
-                    (FT_Long)CUR.GS.projVector.y * CUR.GS.freeVector.y * 4;
+      CUR.F_dot_P = ( (FT_Long)CUR.GS.projVector.x * CUR.GS.freeVector.x +
+                      (FT_Long)CUR.GS.projVector.y * CUR.GS.freeVector.y ) >>
+                    14;
 
     if ( CUR.GS.projVector.x == 0x4000 )
       CUR.func_project = (TT_Project_Func)Project_x;
@@ -2670,7 +2663,7 @@
     CUR.func_move      = (TT_Move_Func)Direct_Move;
     CUR.func_move_orig = (TT_Move_Func)Direct_Move_Orig;
 
-    if ( CUR.F_dot_P == 0x40000000L )
+    if ( CUR.F_dot_P == 0x4000L )
     {
       if ( CUR.GS.freeVector.x == 0x4000 )
       {
@@ -2687,8 +2680,8 @@
     /* at small sizes, F_dot_P can become too small, resulting   */
     /* in overflows and `spikes' in a number of glyphs like `w'. */
 
-    if ( FT_ABS( CUR.F_dot_P ) < 0x4000000L )
-      CUR.F_dot_P = 0x40000000L;
+    if ( FT_ABS( CUR.F_dot_P ) < 0x400L )
+      CUR.F_dot_P = 0x4000L;
 
     /* Disable cached aspect ratio */
     CUR.tt_metrics.ratio = 0;
@@ -5827,12 +5820,8 @@
     else
 #endif
     {
-      *x = FT_MulDiv( d,
-                      (FT_Long)CUR.GS.freeVector.x * 0x10000L,
-                      CUR.F_dot_P );
-      *y = FT_MulDiv( d,
-                      (FT_Long)CUR.GS.freeVector.y * 0x10000L,
-                      CUR.F_dot_P );
+      *x = FT_MulDiv( d, (FT_Long)CUR.GS.freeVector.x, CUR.F_dot_P );
+      *y = FT_MulDiv( d, (FT_Long)CUR.GS.freeVector.y, CUR.F_dot_P );
     }
 
     return SUCCESS;
diff --git a/src/truetype/ttobjs.c b/src/truetype/ttobjs.c
index 53c6fa5ab..c61b218c2 100644
--- a/src/truetype/ttobjs.c
+++ b/src/truetype/ttobjs.c
@@ -764,7 +764,7 @@
     exec->threshold = 0;
 
     exec->instruction_trap = FALSE;
-    exec->F_dot_P          = 0x10000L;
+    exec->F_dot_P          = 0x4000L;
 
     exec->pedantic_hinting = pedantic;