Add support for PAL/European or custom 8K video ROMs (#596)

Added new cmd-line switch: -videorom <file> to replace the video ROM for the Enhanced //e.
- Support video ROM sizes of 4K, 8K and 16K (top 8K only).
- NB. The rocker switch is set to European video ROM.
F10 (for //e or Enhanced //e models) emulates the PAL //e's rocker switch (under the keyboard) to toggle between European or US video ROM.

Other:
- Fixed debugger's view of the AltCharSet soft-switch (it was showing the opposite state).

source/NTSC_CharSet.cpp

@@ -21,10 +21,12 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 #include "StdAfx.h"
 #include "Applewin.h"
+#include "Video.h"
 
 #include "NTSC_CharSet.h"
 
-unsigned char csbits_enhanced2e[2][256][8];	// Enhanced //e
+unsigned char csbits_enhanced2e[2][256][8];	// Enhanced //e (2732 4K video ROM)
+static unsigned char csbits_enhanced2e_pal[2][256][8];	// PAL Enhanced //e (2764 8K video ROM - top 4K) via rocker switch under keyboard
 unsigned char csbits_2e[2][256][8];			// Original //e (no mousetext)
 unsigned char csbits_a2[1][256][8];			// ][ and ][+
 unsigned char csbits_pravets82[1][256][8];	// Pravets 82
@@ -86,6 +88,91 @@ static void get_csbits(csbits_t csbits, const char* resourceName, const UINT cy0
 	delete [] pBuffer;
 }
 
+//-------------------------------------
+
+// ROM address (RA):
+// -----------------
+// . RA10,..,RA3;SEGC,SEGB,SEGA => [2^8][2^3] => 256 chars of 8 lines (total = 2KiB)
+// . VID7,..,VID0 is the 8-bit video character (eg. from TEXT/$400 memory)
+//
+// UTAIIe:8-13, Table 8.2:
+//
+// ALTCHRSET | RA10              | RA9
+//------------------------------------------
+//     0     | VID7 + VID6.FLASH | VID6.VID7
+//     1     | VID7              | VID6
+//
+// FLASH toggles every 16 VBLs, so alternates between selecting NORMAL control/special and INVERSE control/special
+//
+
+void userVideoRom4K(csbits_t csbits, const BYTE* pVideoRom)
+{
+	int RA = 0;	// rom address
+	int i = 0;
+
+	// regular char set
+
+	for (; i<64; i++, RA+=8)		// [00..3F] INVERSE / [40..7F] FLASH
+	{
+		for (int y=0; y<8; y++)
+		{
+			csbits[0][i][y]    = pVideoRom[RA+y] ^ 0xff;	// UTAIIe:8-11 "dot patterns in the video ROM are inverted..."
+			csbits[0][i+64][y] = pVideoRom[RA+y] ^ 0xff;	// UTAIIe:8-14 (Table 8.3) we use FLASH=0, so RA=00ccccccsss
+		}
+	}
+
+	RA = (1<<10 | 0<<9);									// UTAIIe:8-14 (Table 8.3)
+
+	for (i=128; i<256; i++, RA+=8)	// [80..BF] NORMAL
+	{
+		for (int y=0; y<8; y++)
+		{
+			csbits[0][i][y] = pVideoRom[RA+y] ^ 0xff;		// UTAIIe:8-11 "dot patterns in the video ROM are inverted..."
+		}
+	}
+
+	RA = (1<<10 | 1<<9);									// UTAIIe:8-14 (Table 8.3)
+
+	for (i=192; i<256; i++, RA+=8)	// [C0..FF] NORMAL
+	{
+		for (int y=0; y<8; y++)
+		{
+			csbits[0][i][y] = pVideoRom[RA+y] ^ 0xff;		// UTAIIe:8-11 "dot patterns in the video ROM are inverted..."
+		}
+	}
+
+	// alt char set
+
+	RA = 0;
+
+	for (i=0; i<256; i++, RA+=8)	// [00..7F] INVERSE / [80..FF] NORMAL
+	{
+		for (int y=0; y<8; y++)
+		{
+			csbits[1][i][y] = pVideoRom[RA+y] ^ 0xff;		// UTAIIe:8-11 "dot patterns in the video ROM are inverted..."
+		}
+	}
+}
+
+void userVideoRom(void)
+{
+	const BYTE* pVideoRom;
+	UINT size = GetVideoRom(pVideoRom);	// 4K or 8K
+	if (!size)
+		return;
+
+	if (size == kVideoRomSize4K)
+	{
+		userVideoRom4K(&csbits_enhanced2e[0], pVideoRom);
+		return;
+	}
+
+	userVideoRom4K(&csbits_enhanced2e_pal[0], pVideoRom);
+	userVideoRom4K(&csbits_enhanced2e[0], &pVideoRom[4*1024]);
+}
+
+//-------------------------------------
+
 void make_csbits(void)
 {
 	get_csbits(&csbits_enhanced2e[0], TEXT("CHARSET40"), 0);	// Enhanced //e: Alt char set off
@@ -99,4 +186,15 @@ void make_csbits(void)
 	// Original //e is just Enhanced //e with the 32 mousetext chars [0x40..0x5F] replaced by the non-alt charset chars [0x40..0x5F]
 	memcpy(csbits_2e, csbits_enhanced2e, sizeof(csbits_enhanced2e));
 	memcpy(&csbits_2e[1][64], &csbits_2e[0][64], 32*8);
+
+	// Try to use any user-provided video ROM for Enhanced //e
+	userVideoRom();
+}
+
+csbits_t GetEnhanced2e_csbits(void)
+{
+	if (IsVideoRom4K())
+		return csbits_enhanced2e;
+
+	return GetVideoRomRockerSwitch() == false ? csbits_enhanced2e : csbits_enhanced2e_pal;
 }