--- hatari/src/convert/high640x8.c	2019/04/01 07:09:16	1.1
+++ hatari/src/convert/high640x8.c	2019/04/01 07:13:53	1.1.1.5
@@ -1,103 +1,68 @@
-// Screen Conversion, High Res to 640x8Bit
+/*
+  Hatari - high640x8.c
 
-void ConvertHighRes_640x8Bit_YLoop(void);
-void Line_ConvertHighRes_640x8Bit(void);
+  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.
 
-void ConvertHighRes_640x8Bit(void)
-{
-//fprintf(stderr,"FIXME: Screen Conversion, High Res to 640x8Bit\n");
- unsigned char *src=pSTScreen;
- unsigned char *dst=pPCScreenDest;
- int i;
- for(i=0; i<640*400/8; i++, src++)
-  {
-   if( *src & 128 ) *dst++ = 0;  else  *dst++ = 1;
-   if( *src & 64 )  *dst++ = 0;  else  *dst++ = 1;
-   if( *src & 32 )  *dst++ = 0;  else  *dst++ = 1;
-   if( *src & 16 )  *dst++ = 0;  else  *dst++ = 1;
-   if( *src & 8 )   *dst++ = 0;  else  *dst++ = 1;
-   if( *src & 4 )   *dst++ = 0;  else  *dst++ = 1;
-   if( *src & 2 )   *dst++ = 0;  else  *dst++ = 1;
-   if( *src & 1 )   *dst++ = 0;  else  *dst++ = 1;
-  }
- bScreenContentsChanged = TRUE;
-/* FIXME */
-/*
-  __asm {
-    push  ebp
-    push  edi
-    push  esi
-    push  ebx
-
-    mov    edi,[pSTScreen]      // ST format screen 4-plane 16 colours
-    mov    ebp,[pSTScreenCopy]    // Previous ST format screen
-    mov    esi,[pPCScreenDest]    // PC format screen, byte per pixel 256 colours
-    xor    edx,edx        // Clear index for loop
-
-    mov    eax,[STScreenStartHorizLine]
-    mov    [ScrY],eax      // 200 lines
-    jmp    ConvertHighRes_640x8Bit_YLoop
-  }
+  Screen Conversion, High Res to 640x8Bit
 */
-}
 
-/*
-NAKED void ConvertHighRes_640x8Bit_YLoop(void)
-{
-  __asm {
-    // NOTE 'ScrUpdateFlag' is already set(to full update or check, no palettes)
-    jmp    Line_ConvertHighRes_640x8Bit      // 0 palette same, can do check tests
-  }
-}
-NAKED void Line_ConvertHighRes_640x8Bit(void)
+
+static void ConvertHighRes_640x8Bit(void)
 {
-  __asm {
-    mov    [ScrX],40
-x_loop:
-    // Do 16 pixels at one time
-    mov    bx,[edi]
-    // Full update? or just test changes?
-    test  [ScrUpdateFlag],0xe0000000
-    jne    copy_word                // Force
-    // Does differ?
-    cmp    bx,[ebp]
-    je    next_word                // Pixels are same as last frame, so ignore
-
-copy_word:
-    mov    [bScreenContentsChanged],TRUE
-
-    // Plot in 'wrong-order', as ebx is 68000 endian
-    HIGH_BUILD_PIXELS_0                // Generate 'ecx' as pixels [4,5,6,7]
-    PLOT_HIGH_640_8BIT(4)
-    HIGH_BUILD_PIXELS_1                // Generate 'ecx' as pixels [0,1,2,3]
-    PLOT_HIGH_640_8BIT(0)
-    HIGH_BUILD_PIXELS_2                // Generate 'ecx' as pixels [12,13,14,15]
-    PLOT_HIGH_640_8BIT(12)
-    HIGH_BUILD_PIXELS_3                // Generate 'ecx' as pixels [8,9,10,11]
-    PLOT_HIGH_640_8BIT(8)
-
-next_word:
-    add    esi,16                  // Next PC pixels
-    add    edi,2                  // Next ST pixels
-    add    ebp,2                  // Next ST copy pixels
-
-    dec    [ScrX]
-    jne    x_loop                  // Loop on X
-
-    sub    esi,(40*16)                // Back to start of line
-    add    esi,[PCScreenBytesPerLine]        // Offset to next line
-
-    inc    [ScrY]
-    mov    eax,[STScreenEndHorizLine]
-    cmp    [ScrY],eax
-    jne    ConvertHighRes_640x8Bit_YLoop      // And on Y
-
-    pop    ebx
-    pop    esi
-    pop    edi
-    pop    ebp
+	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) ;
+#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) ;
+#endif
+			}
+
+			esi += 4;                               /* Next PC pixels */
+			edi += 1;                               /* Next ST pixels */
+			ebp += 1;                               /* Next ST copy pixels */
+		}
 
-    ret
-  }
+		/*??  esi = esi -40*8 +PCScreenBytesPerLine/2;*/   /* Back to start of line + Offset to next line */
+	}
 }
-*/