diff --git a/src/filters/filters.hpp b/src/filters/filters.hpp
index 15f2faaa..6f74bfef 100644
--- a/src/filters/filters.hpp
+++ b/src/filters/filters.hpp
@@ -4,6 +4,10 @@
 
 #include "interframe.hpp"
 
+// most 16-bit filters require space in src rounded up to u32
+// those that take delta take 1 src line of pixels, rounded up to u32 size
+// initial value appears to be all-0xff
+
 //pixel.cpp
 void Pixelate(u8 *srcPtr, u32 srcPitch, u8 *deltaPtr, u8 *dstPtr, u32 dstPitch, int width, int height);
 void Pixelate32(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */, u8 *dstPtr, u32 dstPitch, int width, int height);
@@ -22,6 +26,7 @@ void ScanlinesTV32(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */, u8 *dstPtr, u3
 // the simple ones could greatly benefit from correct usage of preprocessor..
 // in any case, they are worthless, since all renderers do "simple" or
 // better by default
+int Init_2xSaI(u32 BitFormat);
 void Simple2x16(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
               u8 *dstPtr, u32 dstPitch, int width, int height);
 void Simple2x32(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
@@ -48,6 +53,35 @@ void BilinearPlus(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
 void BilinearPlus32(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
                     u8 *dstPtr, u32 dstPitch, int width, int height);
 
+//admame.cpp
+void AdMame2x(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
+              u8 *dstPtr, u32 dstPitch, int width, int height);
+void AdMame2x32(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
+                u8 *dstPtr, u32 dstPitch, int width, int height);
+
+//2xSal.cpp
+// next 3*2 use Init_2xSaI(555|565) and do not take into account
+int Init_2xSaI(u32 BitFormat);
+// endianness or bit shift variables in init.
+// next 4*2 may be MMX-accelerated
+void _2xSaI (u8 *srcPtr, u32 srcPitch, u8 *deltaPtr,
+             u8 *dstPtr, u32 dstPitch, int width, int height);
+void _2xSaI32 (u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
+               u8 *dstPtr, u32 dstPitch, int width, int height);
+//This one was commented out in other source files
+void Scale_2xSaI (u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
+                  u8 *dstPtr, u32 dstPitch,
+                  u32 dstWidth, u32 dstHeight, int width, int height);
+void Super2xSaI (u8 *srcPtr, u32 srcPitch,
+                 u8 *deltaPtr, u8 *dstPtr, u32 dstPitch,
+                 int width, int height);
+void Super2xSaI32 (u8 *srcPtr, u32 srcPitch,
+                   u8 * /* deltaPtr */, u8 *dstPtr, u32 dstPitch,
+                   int width, int height);
+void SuperEagle (u8 *srcPtr, u32 srcPitch, u8 *deltaPtr,
+                 u8 *dstPtr, u32 dstPitch, int width, int height);
+void SuperEagle32 (u8 *srcPtr, u32 srcPitch, u8 *deltaPtr,
+                   u8 *dstPtr, u32 dstPitch, int width, int height);
 //hq2x.cpp
 //These require calling hq2x_init first and whenever bpp changes
 /*static void hq2x_16_def(u16* dst0, u16* dst1, const u16* src0, const u16* src1, const u16* src2, unsigned count);
@@ -64,4 +98,28 @@ void lq2x(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
 void lq2x32(u8 *srcPtr, u32 srcPitch, u8 * /* deltaPtr */,
             u8 *dstPtr, u32 dstPitch, int width, int height);
 
+//hq/asm/hq3x32.cpp
+//16 bit input, see below for 32 bit input
+// note: 16-bit input for asm version only!
+void hq3x32(unsigned char * pIn,  unsigned int srcPitch,
+            unsigned char *,
+            unsigned char * pOut, unsigned int dstPitch,
+            int Xres, int Yres);
+void hq4x32(unsigned char * pIn,  unsigned int srcPitch,
+            unsigned char *,
+            unsigned char * pOut, unsigned int dstPitch,
+            int Xres, int Yres);
+void hq3x16(unsigned char * pIn,  unsigned int srcPitch,
+            unsigned char *,
+            unsigned char * pOut, unsigned int dstPitch,
+            int Xres, int Yres);
+void hq4x16(unsigned char * pIn,  unsigned int srcPitch,
+            unsigned char *,
+            unsigned char * pOut, unsigned int dstPitch,
+            int Xres, int Yres);
+// this takes 32-bit input
+// (by converting to 16-bit first in asm version
+void hq3x32_32(unsigned char *pIn,  unsigned int srcPitch, unsigned char *, unsigned char *pOut, unsigned int dstPitch, int Xres, int Yres);
+void hq4x32_32(unsigned char *pIn,  unsigned int srcPitch, unsigned char *, unsigned char *pOut, unsigned int dstPitch, int Xres, int Yres);
+
 #endif //FILTERS_FILTERS_HPP
diff --git a/src/gtk/filters.cpp b/src/gtk/filters.cpp
index a092b19d..f2f546d8 100644
--- a/src/gtk/filters.cpp
+++ b/src/gtk/filters.cpp
@@ -18,20 +18,6 @@
 
 #include "filters.h"
 #include "intl.h"
-#include "../filters/filters.hpp"
-
-void _2xSaI        (u8 *, u32, u8 *, u8 *, u32, int, int);
-void _2xSaI32      (u8 *, u32, u8 *, u8 *, u32, int, int);
-void Super2xSaI    (u8 *, u32, u8 *, u8 *, u32, int, int);
-void Super2xSaI32  (u8 *, u32, u8 *, u8 *, u32, int, int);
-void SuperEagle    (u8 *, u32, u8 *, u8 *, u32, int, int);
-void SuperEagle32  (u8 *, u32, u8 *, u8 *, u32, int, int);
-void AdMame2x      (u8 *, u32, u8 *, u8 *, u32, int, int);
-void AdMame2x32    (u8 *, u32, u8 *, u8 *, u32, int, int);
-void hq2x          (u8 *, u32, u8 *, u8 *, u32, int, int);
-void hq2x32        (u8 *, u32, u8 *, u8 *, u32, int, int);
-void lq2x          (u8 *, u32, u8 *, u8 *, u32, int, int);
-void lq2x32        (u8 *, u32, u8 *, u8 *, u32, int, int);
 
 namespace VBA
 {
diff --git a/src/gtk/filters.h b/src/gtk/filters.h
index bc4dea60..b5ec4ff8 100644
--- a/src/gtk/filters.h
+++ b/src/gtk/filters.h
@@ -21,8 +21,7 @@
 #define __VBA_FILTERS_H__
 
 #include "../System.h"
-
-int Init_2xSaI(u32);
+#include "../filters/filters.hpp"
 
 namespace VBA
 {
diff --git a/src/sdl/filters.cpp b/src/sdl/filters.cpp
index 7ba760f5..9955770d 100644
--- a/src/sdl/filters.cpp
+++ b/src/sdl/filters.cpp
@@ -24,26 +24,12 @@
       // Screen filters
       //
 
-extern int Init_2xSaI(u32);
-extern void hq2x_init(unsigned);
 extern bool sdlStretchInit(int colorDepth, int sizeMultiplier, int srcWidth);
 
 extern void sdlStretch1x(u8*,u32,u8*,u8*,u32,int,int);
 extern void sdlStretch2x(u8*,u32,u8*,u8*,u32,int,int);
 extern void sdlStretch3x(u8*,u32,u8*,u8*,u32,int,int);
 extern void sdlStretch4x(u8*,u32,u8*,u8*,u32,int,int);
-extern void _2xSaI(u8*,u32,u8*,u8*,u32,int,int);
-extern void _2xSaI32(u8*,u32,u8*,u8*,u32,int,int);
-extern void Super2xSaI(u8*,u32,u8*,u8*,u32,int,int);
-extern void Super2xSaI32(u8*,u32,u8*,u8*,u32,int,int);
-extern void SuperEagle(u8*,u32,u8*,u8*,u32,int,int);
-extern void SuperEagle32(u8*,u32,u8*,u8*,u32,int,int);
-extern void AdMame2x(u8*,u32,u8*,u8*,u32,int,int);
-extern void AdMame2x32(u8*,u32,u8*,u8*,u32,int,int);
-extern void hq3x16(u8*,u32,u8*,u8*,u32,int,int);
-extern void hq4x16(u8*,u32,u8*,u8*,u32,int,int);
-extern void hq3x32_32(u8*,u32,u8*,u8*,u32,int,int);
-extern void hq4x32_32(u8*,u32,u8*,u8*,u32,int,int);
 
 struct FilterDesc {
 	char name[30];
diff --git a/src/wx/filters.h b/src/wx/filters.h
deleted file mode 100644
index 86935c54..00000000
--- a/src/wx/filters.h
+++ /dev/null
@@ -1,39 +0,0 @@
-#ifndef FILTERS_H
-#define FILTERS_H
-
-// FIXME: these should be in a system header included by all users and all
-// files which define these functions
-// most 16-bit filters require space in src rounded up to u32
-// those that take delta take 1 src line of pixels, rounded up to u32 size
-// initial value appears to be all-0xff
-
-#include "../filters/filters.hpp"
-
-// next 3*2 use Init_2xSaI(555|565) and do not take into account
-int Init_2xSaI(u32 BitFormat);
-// endianness or bit shift variables in init.
-// next 4*2 may be MMX-accelerated
-void _2xSaI32(u8 *src, u32 spitch, u8 *delta, u8 *dst, u32 dstp, int w, int h);
-void _2xSaI(u8 *src, u32 spitch, u8 *delta, u8 *dst, u32 dstp, int w, int h);
-// void Scale_2xSaI(u8 *src, u32 spitch, u8 *, u8 *dst, u32 dstp, int w, int h);
-void Super2xSaI32(u8 *src, u32 spitch, u8 *delta, u8 *dst, u32 dstp, int w, int h);
-void Super2xSaI(u8 *src, u32 spitch, u8 *delta, u8 *dst, u32 dstp, int w, int h);
-void SuperEagle32(u8 *src, u32 spitch, u8 *delta, u8 *dst, u32 dstp, int w, int h);
-void SuperEagle(u8 *src, u32 spitch, u8 *delta, u8 *dst, u32 dstp, int w, int h);
-void AdMame2x32(u8 *src, u32 spitch, u8 *, u8 *dst, u32 dstp, int w, int h);
-void AdMame2x(u8 *src, u32 spitch, u8 *, u8 *dst, u32 dstp, int w, int h);
-
-// note: 16-bit input for asm version only!
-void hq3x32(u8 *src, u32 spitch, u8 *, u8 *dst, u32 dstp, int w, int h);
-// this takes 32-bit input
-// (by converting to 16-bit first in asm version)
-void hq3x32_32(u8 *src, u32 spitch, u8 *, u8 *dst, u32 dstp, int w, int h);
-void hq3x16(u8 *src, u32 spitch, u8 *, u8 *dst, u32 dstp, int w, int h);
-// note: 16-bit input for asm version only!
-void hq4x32(u8 *src, u32 spitch, u8 *, u8 *dst, u32 dstp, int w, int h);
-// this takes 32-bit input
-// (by converting to 16-bit first in asm version)
-void hq4x32_32(u8 *src, u32 spitch, u8 *, u8 *dst, u32 dstp, int w, int h);
-void hq4x16(u8 *src, u32 spitch, u8 *, u8 *dst, u32 dstp, int w, int h);
-
-#endif /* FILTERS_H */
diff --git a/src/wx/wxvbam.h b/src/wx/wxvbam.h
index f6404e20..942887d0 100644
--- a/src/wx/wxvbam.h
+++ b/src/wx/wxvbam.h
@@ -561,6 +561,6 @@ extern int joypress[4], autofire;
 #define KEYM_MOTION_LEFT  (1<<17)
 #define KEYM_MOTION_RIGHT (1<<18)
 
-#include "filters.h"
+#include "../filters/filters.hpp"
 
 #endif /* WX_WXVBAM_H */