Added support for Apple II/II+ 2K video ROMs (fixes #205)

source/Applewin.cpp

@@ -1289,14 +1289,14 @@ int APIENTRY WinMain(HINSTANCE passinstance, HINSTANCE, LPSTR lpCmdLine, int)
 			if ((g_hCustomRomF8 == INVALID_HANDLE_VALUE) || (GetFileSize(g_hCustomRomF8, NULL) != 0x800))
 				g_bCustomRomF8Failed = true;
 		}
-		else if (strcmp(lpCmdLine, "-videorom") == 0)			// Use 4K,8K or 16K video ROM for Enhanced //e
+		else if (strcmp(lpCmdLine, "-videorom") == 0)			// Use 2K (for II/II+). Use 4K,8K or 16K video ROM (for Enhanced //e)
 		{
 			lpCmdLine = GetCurrArg(lpNextArg);
 			lpNextArg = GetNextArg(lpNextArg);
 
 			if (!ReadVideoRomFile(lpCmdLine))
 			{
-				std::string msg = "Failed to load video rom (not found or not exactly 4/8/16KiB)";
+				std::string msg = "Failed to load video rom (not found or not exactly 2/4/8/16KiB)";
 				LogFileOutput("%s", msg.c_str());
 				MessageBox(g_hFrameWindow, msg.c_str(), TEXT("AppleWin Error"), MB_OK);
 			}

source/NTSC_CharSet.cpp

@@ -154,11 +154,11 @@ void userVideoRom4K(csbits_t csbits, const BYTE* pVideoRom)
 	}
 }
 
-void userVideoRom(void)
+void userVideoRomForIIe(void)
 {
 	const BYTE* pVideoRom;
-	UINT size = GetVideoRom(pVideoRom);	// 4K or 8K
+	UINT size = GetVideoRom(pVideoRom);	// 2K or 4K or 8K
-	if (!size)
+	if (size < kVideoRomSize4K)
 		return;
 
 	if (size == kVideoRomSize4K)
@@ -173,6 +173,50 @@ void userVideoRom(void)
 
 //-------------------------------------
 
+void userVideoRom2K(csbits_t csbits, const BYTE* pVideoRom)
+{
+	int RA = 0;	// rom address
+
+	for (int i=0; i<256; i++, RA+=8)
+	{
+		for (int y=0; y<8; y++)
+		{
+			BYTE d=0;
+			BYTE n = pVideoRom[RA+y];
+
+			// UTAII:8-30 "Bit 7 of your EPROM fonts will control flashing in the lower 1024 bytes of the EPROM"
+			// UTAII:8-31 "If you leave O7 (EPROM Output7) reset in these patterns, the resulting characters will be inversions..."
+			if (!(n & 0x80) && RA < 1024)
+				n = n ^ 0x7f;
+			n &= 0x7f;
+
+			// UTAII:8-30 "TEXT ROM pattern is ... reversed"
+			for (BYTE j=0; j<7; j++)
+			{
+				if (n & 1)
+					d |= 1;
+				d <<= 1;
+				n >>= 1;
+			}
+
+			d >>= 1;	// Undo the last left shift
+			csbits[0][i][y] = d;
+		}
+	}
+}
+
+void userVideoRomForIIPlus(void)
+{
+	const BYTE* pVideoRom;
+	UINT size = GetVideoRom(pVideoRom);	// 2K or 4K or 8K
+	if (size != kVideoRomSize2K)
+		return;
+
+	userVideoRom2K(&csbits_a2[0], pVideoRom);
+}
+
+//-------------------------------------
+
 void make_csbits(void)
 {
 	get_csbits(&csbits_enhanced2e[0], TEXT("CHARSET40"), 0);	// Enhanced //e: Alt char set off
@@ -188,7 +232,10 @@ void make_csbits(void)
 	memcpy(&csbits_2e[1][64], &csbits_2e[0][64], 32*8);
 
 	// Try to use any user-provided video ROM for Enhanced //e
-	userVideoRom();
+	userVideoRomForIIe();
+
+	// Try to use any user-provided video ROM for II/II+
+	userVideoRomForIIPlus();
 }
 
 csbits_t GetEnhanced2e_csbits(void)

source/Video.cpp

@@ -1160,7 +1160,7 @@ bool ReadVideoRomFile(const char* pRomFile)
 		return false;
 
 	const ULONG size = GetFileSize(h, NULL);
-	if (size == kVideoRomSize4K || size == kVideoRomSize8K || size == kVideoRomSize16K)
+	if (size == kVideoRomSize2K || size == kVideoRomSize4K || size == kVideoRomSize8K || size == kVideoRomSize16K)
 	{
 		DWORD bytesRead;
 		if (ReadFile(h, g_videoRom, size, &bytesRead, NULL) && bytesRead == size)
@@ -1197,7 +1197,7 @@ void SetVideoRomRockerSwitch(bool state)
 
 bool IsVideoRom4K(void)
 {
-	return g_videoRomSize == 0 || g_videoRomSize == kVideoRomSize4K;
+	return g_videoRomSize <= kVideoRomSize4K;
 }
 
 //===========================================================================

source/Video.h

@@ -200,7 +200,8 @@ void Video_SetBitmapHeader( WinBmpHeader_t *pBmp, int nWidth, int nHeight, int n
 
 BYTE VideoSetMode(WORD pc, WORD addr, BYTE bWrite, BYTE d, ULONG uExecutedCycles);
 
-const UINT kVideoRomSize4K = 4*1024;
+const UINT kVideoRomSize2K = 1024*2;
+const UINT kVideoRomSize4K = kVideoRomSize2K*2;
 bool ReadVideoRomFile(const char* pRomFile);
 UINT GetVideoRom(const BYTE*& pVideoRom);
 bool GetVideoRomRockerSwitch(void);