--- hatari/src/convert/high640x8.c	2019/04/01 07:12:50	1.1.1.4
+++ hatari/src/convert/high640x8.c	2019/04/09 08:50:37	1.1.1.8
@@ -1,90 +1,68 @@
-/* Screen Conversion, High Res to 640x8Bit */
-
+/*
+  Hatari - high640x8.c
 
-static void ConvertHighRes_640x8Bit(void)
-{
-  Uint16 *edi, *ebp;
-  Uint32 *esi;
-  Uint16 eax, ebx;
-  int y, x;
+  This file is distributed under the GNU Public License, version 2 or at your
+  option any later version. Read the file gpl.txt for details.
 
-/*
-  // This is the method that I first used in Hatari...
-  // ...but I now rewrote the old WinSTon method, too.
-  // Don't know what is faster, so I didn't removed my
-  // first method here completely...
-  Uint8 *src=pSTScreen;
-  Uint8 *osrc=pSTScreenCopy;
-  Uint8 *dst=pPCScreenDest;
-  int i;
-  for(i=0; i<640*400/8; i++, src++, osrc++)
-   {
-    if( *osrc==*src )
-      dst+=8;
-     else
-     {
-      if( *src & 128 ) *dst++ = 1;  else  *dst++ = 0;
-      if( *src & 64 )  *dst++ = 1;  else  *dst++ = 0;
-      if( *src & 32 )  *dst++ = 1;  else  *dst++ = 0;
-      if( *src & 16 )  *dst++ = 1;  else  *dst++ = 0;
-      if( *src & 8 )   *dst++ = 1;  else  *dst++ = 0;
-      if( *src & 4 )   *dst++ = 1;  else  *dst++ = 0;
-      if( *src & 2 )   *dst++ = 1;  else  *dst++ = 0;
-      if( *src & 1 )   *dst++ = 1;  else  *dst++ = 0;
-     }
-   }
-  bScreenContentsChanged = TRUE;
-  return;
+  Screen Conversion, High Res to 640x8Bit
 */
 
-  /* Here's now the rewrite of the original WinSTon method: */
 
-  edi = (Uint16 *)pSTScreen;        /* ST format screen */
-  ebp = (Uint16 *)pSTScreenCopy;    /* Previous ST format screen */
-  esi = (Uint32 *)pPCScreenDest;    /* PC format screen */
-
-  /* NOTE 'ScrUpdateFlag' is already set (to full update or check, no palettes) */
-  
-  for (y = STScreenStartHorizLine; y < STScreenEndHorizLine; y++) {
-
-    for (x = 0; x < 40; x++) {
-
-      /* Do 16 pixels at one time */
-      ebx = *edi;
-      
-      if( (ScrUpdateFlag&0xe0000000) || ebx!=*ebp )  /* Does differ? */
-       {
-        bScreenContentsChanged = TRUE;
+static void ConvertHighRes_640x8Bit(void)
+{
+	Uint16 *edi, *ebp;
+	Uint32 *esi;
+	Uint16 eax, ebx;
+	int y, x, update;
+
+	edi = (Uint16 *)pSTScreen;        /* ST format screen */
+	ebp = (Uint16 *)pSTScreenCopy;    /* Previous ST format screen */
+	esi = (Uint32 *)pPCScreenDest;    /* PC format screen */
+
+	/* NOTE 'ScrUpdateFlag' is already set (to full update or check, no palettes) */
+	update = ScrUpdateFlag & PALETTEMASK_UPDATEMASK;
+
+	for (y = STScreenStartHorizLine; y < STScreenEndHorizLine; y++)
+	{
+
+		for (x = 0; x < 40; x++)
+		{
+
+			/* Do 16 pixels at one time */
+			ebx = *edi;
+
+			if (update || ebx != *ebp)  /* Does differ? */
+			{
+				bScreenContentsChanged = true;
 
 #if SDL_BYTEORDER == SDL_BIG_ENDIAN
-        /* Plot in 'right-order' on big endian systems */
-        HIGH_BUILD_PIXELS_0 ;               /* Generate pixels [4,5,6,7] */
-        PLOT_HIGH_640_8BIT(3) ;
-        HIGH_BUILD_PIXELS_1 ;               /* Generate pixels [0,1,2,3] */
-        PLOT_HIGH_640_8BIT(2) ;
-        HIGH_BUILD_PIXELS_2 ;               /* Generate pixels [12,13,14,15] */
-        PLOT_HIGH_640_8BIT(1) ;
-        HIGH_BUILD_PIXELS_3 ;               /* Generate pixels [8,9,10,11] */
-        PLOT_HIGH_640_8BIT(0) ;
+				/* Plot in 'right-order' on big endian systems */
+				HIGH_BUILD_PIXELS_0 ;               /* Generate pixels [12,13,14,15] */
+				PLOT_HIGH_640_8BIT(3) ;
+				HIGH_BUILD_PIXELS_1 ;               /* Generate pixels [8,9,10,11] */
+				PLOT_HIGH_640_8BIT(2) ;
+				HIGH_BUILD_PIXELS_2 ;               /* Generate pixels [4,5,6,7] */
+				PLOT_HIGH_640_8BIT(1) ;
+				HIGH_BUILD_PIXELS_3 ;               /* Generate pixels [0,1,2,3] */
+				PLOT_HIGH_640_8BIT(0) ;
 #else
-        /* Plot in 'wrong-order', as ebx is 68000 endian */
-        HIGH_BUILD_PIXELS_0 ;               /* Generate pixels [4,5,6,7] */
-        PLOT_HIGH_640_8BIT(1) ;
-        HIGH_BUILD_PIXELS_1 ;               /* Generate pixels [0,1,2,3] */
-        PLOT_HIGH_640_8BIT(0) ;
-        HIGH_BUILD_PIXELS_2 ;               /* Generate pixels [12,13,14,15] */
-        PLOT_HIGH_640_8BIT(3) ;
-        HIGH_BUILD_PIXELS_3 ;               /* Generate pixels [8,9,10,11] */
-        PLOT_HIGH_640_8BIT(2) ;
+				/* Plot in 'wrong-order', as ebx is 68000 endian */
+				HIGH_BUILD_PIXELS_0 ;               /* Generate pixels [4,5,6,7] */
+				PLOT_HIGH_640_8BIT(1) ;
+				HIGH_BUILD_PIXELS_1 ;               /* Generate pixels [0,1,2,3] */
+				PLOT_HIGH_640_8BIT(0) ;
+				HIGH_BUILD_PIXELS_2 ;               /* Generate pixels [12,13,14,15] */
+				PLOT_HIGH_640_8BIT(3) ;
+				HIGH_BUILD_PIXELS_3 ;               /* Generate pixels [8,9,10,11] */
+				PLOT_HIGH_640_8BIT(2) ;
 #endif
-       }
+			}
 
-     esi += 4;                              /* Next PC pixels */
-     edi += 1;                              /* Next ST pixels */
-     ebp += 1;                              /* Next ST copy pixels */
-    }
+			esi += 4;                               /* Next PC pixels */
+			edi += 1;                               /* Next ST pixels */
+			ebp += 1;                               /* Next ST copy pixels */
+		}
 
-/*??  esi = esi -40*8 +PCScreenBytesPerLine/2;*/   /* Back to start of line + Offset to next line */
-  }
+		esi += PCScreenBytesPerLine/4 - 40*4;           /* advance to start of next line */
+	}
 }
-