AppleWin/source/NTSC_CharSet.cpp

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/*
AppleWin : An Apple //e emulator for Windows
Copyright (C) 2010-2011, William S Simms
Copyright (C) 2016, Tom Charlesworth
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AppleWin is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
AppleWin is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with AppleWin; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "StdAfx.h"
#include "Applewin.h"
#include "Video.h"
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#include "NTSC_CharSet.h"
unsigned char csbits_enhanced2e[2][256][8]; // Enhanced //e (2732 4K video ROM)
static unsigned char csbits_2e_pal[2][256][8]; // PAL Original or Enhanced //e (2764 8K video ROM - low 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
unsigned char csbits_pravets8M[1][256][8]; // Pravets 8M
unsigned char csbits_pravets8C[2][256][8]; // Pravets 8A & 8C
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//
static const UINT bitmapWidth = 256;
static const UINT bitmapWidthBytes = bitmapWidth/8;
static const UINT bitmapHeight = 768;
static const UINT charWidth = 16;
static const UINT charWidthBytes = 16/8;
static const UINT charHeight = 16;
static void get_csbits_xy(csbits_t csbits, UINT ch, UINT cx, UINT cy, const BYTE* pBitmap)
{
_ASSERT(ch < 256);
_ASSERT((cx < bitmapWidth/charWidth) && (cy < bitmapHeight/charHeight));
pBitmap += cy*charHeight*bitmapWidthBytes + cx*charWidthBytes;
for (UINT y=0; y<8; y++)
{
BYTE n = 0;
for (int x=0; x<14; x+=2)
{
UINT xp = x/8;
BYTE d = pBitmap[xp];
UINT b = 7 - x%8;
if (d & (1<<b)) n |= 0x80;
n >>= 1;
}
csbits[0][ch][y] = n;
pBitmap += bitmapWidthBytes*2;
}
}
static void get_csbits(csbits_t csbits, const char* resourceName, const UINT cy0)
{
const UINT bufferSize = bitmapWidthBytes*bitmapHeight;
BYTE* pBuffer = new BYTE [bufferSize];
HBITMAP hCharBitmap = LoadBitmap(g_hInstance, resourceName);
GetBitmapBits(hCharBitmap, bufferSize, pBuffer);
for (UINT cy=cy0, ch=0; cy<cy0+16; cy++)
{
for (UINT cx=0; cx<16; cx++)
{
get_csbits_xy(csbits, ch++, cx, cy, pBuffer);
}
}
DeleteObject(hCharBitmap);
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 userVideoRomForIIe(void)
{
const BYTE* pVideoRom;
UINT size = GetVideoRom(pVideoRom); // 2K or 4K or 8K
if (size < kVideoRomSize4K)
return;
if (size == kVideoRomSize4K)
{
userVideoRom4K(&csbits_enhanced2e[0], pVideoRom);
}
else
{
userVideoRom4K(&csbits_2e_pal[0], pVideoRom);
userVideoRom4K(&csbits_enhanced2e[0], &pVideoRom[4*1024]);
}
// NB. Same *custom* US video ROM for Original & Enhanced //e
memcpy(csbits_2e, csbits_enhanced2e, sizeof(csbits_enhanced2e));
}
//-------------------------------------
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 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;
// UTAII:8-30 "TEXT ROM pattern is ... reversed"
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BYTE d = 0;
for (BYTE j=0; j<7; j++, n >>= 1) // Just bits [0..6]
d = (d << 1) | (n & 1);
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
get_csbits(&csbits_enhanced2e[1], TEXT("CHARSET40"), 16); // Enhanced //e: Alt char set on (mousetext)
get_csbits(&csbits_a2[0], TEXT("CHARSET40"), 32); // Apple ][, ][+
get_csbits(&csbits_pravets82[0], TEXT("CHARSET82"), 0); // Pravets 82
get_csbits(&csbits_pravets8M[0], TEXT("CHARSET8M"), 0); // Pravets 8M
get_csbits(&csbits_pravets8C[0], TEXT("CHARSET8C"), 0); // Pravets 8A / 8C: Alt char set off
get_csbits(&csbits_pravets8C[1], TEXT("CHARSET8C"), 16); // Pravets 8A / 8C: Alt char set on
// 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 Original/Enhanced //e
userVideoRomForIIe();
// Try to use any user-provided video ROM for II/II+
userVideoRomForIIPlus();
}
csbits_t Get2e_csbits(void)
{
const csbits_t videoRom4K = (GetApple2Type() == A2TYPE_APPLE2E) ? csbits_2e : csbits_enhanced2e;
if (IsVideoRom4K()) // 4K means US-only, so no secondary PAL video ROM
return videoRom4K;
return GetVideoRomRockerSwitch() == false ? videoRom4K : csbits_2e_pal; // NB. Same PAL video ROM for Original & Enhanced //e
}