AppleWin/source/VidHD.cpp

/*
  AppleWin : An Apple //e emulator for Windows

  Copyright (C) 1994-1996, Michael O'Brien
  Copyright (C) 1999-2001, Oliver Schmidt
  Copyright (C) 2002-2005, Tom Charlesworth
  Copyright (C) 2006-2021, Tom Charlesworth, Michael Pohoreski

  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
*/
/*
  Emulate a VidHD card (Blue Shift Inc)
  * Partial support only *

  Allows any Apple II to support the IIgs' 320x200 and 640x200 256-colour Super High-Res video modes.

  NB. Not supported yet:
  . Apple II/II+ support for //e video modes (TEXT80, DGR, DHGR).
  . IIgs SCREEN & BORDER COLOR.
  . IIgs B&W DHGR.
  . The VidHD extended text modes 80x45, 120x67, 240x135 (and setting FG/BG colours).
  . Enable/disable VidHD soft-switch.

  Implementation notes:
  . II/II+
    . Mirrors the 80STORE/PAGE2/AUXREAD/AUXWRITE switches to VidHD.
    . Reuses 'memaux' that's for the //e models.
    . AUXWRITE=1: writes occur to both main & memaux.
    . 80STORE=1 && PAGE2=1: same as AUXWRITE=1 (but should be changed to *only* allow writes to aux's TEXT1 & HGR2 areas).
    . Only 6502 (not 65C02) emulation supports this dual write to main & memaux (via the 'memVidHD' pointer):
      - So a II/II+ with a 65C02 won't correctly support VidHD cards.
      - And a //e with a 6502 will incur a slight overhead to test 'memVidHD' pointer (which is always NULL for //e's).
    . VidHD card's save-state includes VidHD's aux mem ($400-$9FFF).
  . //e with 1KiB 80-Col card: AppleWin doesn't support this - so currently out of scope.
*/

#include "StdAfx.h"

#include "Core.h"
#include "Memory.h"
#include "Video.h"
#include "VidHD.h"
#include "YamlHelper.h"

void VidHDCard::Reset(const bool powerCycle)
{
	m_NEWVIDEO = 0;
	GetVideo().SetVideoMode(GetVideo().GetVideoMode() & ~VF_SHR);
}

void VidHDCard::InitializeIO(LPBYTE pCxRomPeripheral)
{
	RegisterIoHandler(m_slot, IO_Null, IO_Null, &VidHDCard::IORead, IO_Null, this, NULL);
}

BYTE __stdcall VidHDCard::IORead(WORD pc, WORD addr, BYTE bWrite, BYTE value, ULONG nExecutedCycles)
{
	// Return magic bytes (from the VidHD firmware) for VidHD detection
	switch (addr & 0xff)
	{
	case 0: return 0x24;
	case 1: return 0xEA;
	case 2: return 0x4C;
	}
	return IO_Null(pc, addr, bWrite, value, nExecutedCycles);
}

// NB. VidHD has no support for reading the IIgs video registers (from an earlier Apple II)
void VidHDCard::VideoIOWrite(WORD pc, WORD addr, BYTE bWrite, BYTE value, ULONG nExecutedCycles)
{
	switch (addr & 0xff)
	{
	case 0x00: m_memMode &= ~MF_80STORE;	break;
	case 0x01: m_memMode |= MF_80STORE;		break;
	case 0x02: m_memMode &= ~MF_AUXREAD;	break;
	case 0x03: m_memMode |= MF_AUXREAD;		break;
	case 0x04: m_memMode &= ~MF_AUXWRITE;	break;
	case 0x05: m_memMode |= MF_AUXWRITE;	break;
	case 0x54: m_memMode &= ~MF_PAGE2;		break;
	case 0x55: m_memMode |= MF_PAGE2;		break;
	// IIgs registers
	case 0x22: m_SCREENCOLOR = value;		break;
	case 0x29: m_NEWVIDEO = value;			break;
	case 0x34: m_BORDERCOLOR = value;		break;
	case 0x35: m_SHADOW = value;			break;
	}
}

bool VidHDCard::IsWriteAux(void)
{
	return (m_memMode & MF_AUXWRITE) ||							// Write to aux: $200-$BFFF
		((m_memMode & MF_80STORE) && (m_memMode & MF_PAGE2));	// Write to aux: $400-$7FF and $2000-$3FFF
}

//===========================================================================

#pragma pack(push)
#pragma pack(1)	// Ensure struct is packed
struct Color
{
	USHORT blue : 4;
	USHORT green : 4;
	USHORT red : 4;
	USHORT reserved : 4;
};
#pragma pack(pop)

bgra_t ConvertIIgs2RGB(Color color)
{
	bgra_t rgb = { 0 };
	rgb.r = color.red * 16;
	rgb.g = color.green * 16;
	rgb.b = color.blue * 16;
	rgb.a = ALPHA;
	return rgb;
}

void VidHDCard::UpdateSHRCell(bool is640Mode, bool isColorFillMode, uint16_t addrPalette, bgra_t* pVideoAddress, uint32_t a)
{
	_ASSERT(!is640Mode);		// to do: test this mode

	Color* palette = (Color*) MemGetAuxPtr(addrPalette);

	for (UINT i = 0; i < 4; i++)
	{
		if (!is640Mode) // 320 mode
		{
			BYTE pixel1 = (a >> 4) & 0xf;
			bgra_t color1 = ConvertIIgs2RGB(palette[pixel1]);
			if (isColorFillMode && pixel1 == 0) color1 = *(pVideoAddress - 1);
			*pVideoAddress++ = color1;
			*pVideoAddress++ = color1;

			BYTE pixel2 = a & 0xf;
			bgra_t color2 = ConvertIIgs2RGB(palette[pixel2]);
			if (isColorFillMode && pixel2 == 0) color2 = color1;
			*pVideoAddress++ = color2;
			*pVideoAddress++ = color2;
		}
		else // 640 mode - see IIgs Hardware Ref, Pg.96, Table4-21 'Color Selection in 640 mode'
		{
			BYTE pixel1 = (a >> 6) & 0x3;
			bgra_t color1 = ConvertIIgs2RGB(palette[0x8 + pixel1]);
			*pVideoAddress++ = color1;

			BYTE pixel2 = (a >> 4) & 0x3;
			bgra_t color2 = ConvertIIgs2RGB(palette[0xC + pixel2]);
			*pVideoAddress++ = color2;

			BYTE pixel3 = (a >> 2) & 0x3;
			bgra_t color3 = ConvertIIgs2RGB(palette[0x0 + pixel3]);
			*pVideoAddress++ = color3;

			BYTE pixel4 = a & 0x3;
			bgra_t color4 = ConvertIIgs2RGB(palette[0x4 + pixel4]);
			*pVideoAddress++ = color4;
		}

		a >>= 8;
	}
}

//===========================================================================

static const UINT kUNIT_VERSION = 1;

#define SS_YAML_KEY_MEMORYMODE "Memory Mode"
#define SS_YAML_KEY_SCREEN_COLOR "Screen Color"
#define SS_YAML_KEY_NEW_VIDEO "New Video"
#define SS_YAML_KEY_BORDER_COLOR "Border Color"
#define SS_YAML_KEY_SHADOW "Shadow"

const std::string& VidHDCard::GetSnapshotCardName(void)
{
	static const std::string name("VidHD");
	return name;
}

static const std::string& MemGetSnapshotAuxMemStructName(void)
{
	static const std::string name("Auxiliary Memory Bank");
	return name;
}

void VidHDCard::SaveSnapshot(YamlSaveHelper& yamlSaveHelper)
{
	YamlSaveHelper::Slot slot(yamlSaveHelper, GetSnapshotCardName(), m_slot, kUNIT_VERSION);

	YamlSaveHelper::Label unit(yamlSaveHelper, "%s:\n", SS_YAML_KEY_STATE);
	yamlSaveHelper.SaveHexUint32(SS_YAML_KEY_MEMORYMODE, m_memMode);
	yamlSaveHelper.SaveHexUint8(SS_YAML_KEY_SCREEN_COLOR, m_SCREENCOLOR);
	yamlSaveHelper.SaveHexUint8(SS_YAML_KEY_NEW_VIDEO, m_NEWVIDEO);
	yamlSaveHelper.SaveHexUint8(SS_YAML_KEY_BORDER_COLOR, m_BORDERCOLOR);
	yamlSaveHelper.SaveHexUint8(SS_YAML_KEY_SHADOW, m_SHADOW);

	if (IsApple2PlusOrClone(GetApple2Type()))	// Save aux mem for II/II+
	{
		// Save [$400-$9FFF]
		YamlSaveHelper::Label state(yamlSaveHelper, "%s:\n", MemGetSnapshotAuxMemStructName().c_str());

		LPBYTE pMemBase = MemGetBankPtr(1, true);
		yamlSaveHelper.SaveMemory(pMemBase, (SHR_MEMORY_END + 1) - TEXT_PAGE1_BEGIN, TEXT_PAGE1_BEGIN);
	}
}

bool VidHDCard::LoadSnapshot(YamlLoadHelper& yamlLoadHelper, UINT version)
{
	if (version < 1 || version > kUNIT_VERSION)
		ThrowErrorInvalidVersion(version);

	m_memMode = yamlLoadHelper.LoadUint(SS_YAML_KEY_MEMORYMODE);
	m_SCREENCOLOR = yamlLoadHelper.LoadUint(SS_YAML_KEY_SCREEN_COLOR);
	m_NEWVIDEO = yamlLoadHelper.LoadUint(SS_YAML_KEY_NEW_VIDEO);
	m_BORDERCOLOR = yamlLoadHelper.LoadUint(SS_YAML_KEY_BORDER_COLOR);
	m_SHADOW = yamlLoadHelper.LoadUint(SS_YAML_KEY_SHADOW);

	if (IsApple2PlusOrClone(GetApple2Type()))	// Load aux mem for II/II+
	{
		// Load [$400-$9FFF]
		if (!yamlLoadHelper.GetSubMap(MemGetSnapshotAuxMemStructName()))
			throw std::runtime_error("Memory: Missing map name: " + MemGetSnapshotAuxMemStructName());

		LPBYTE pMemBase = MemGetBankPtr(1, false);
		yamlLoadHelper.LoadMemory(pMemBase, (SHR_MEMORY_END + 1) - TEXT_PAGE1_BEGIN, TEXT_PAGE1_BEGIN);

		yamlLoadHelper.PopMap();
	}

	return true;
}