dosbox-wii/src/hardware/vga_attr.cpp

/*
 *  Copyright (C) 2002  The DOSBox Team
 *
 *  This program 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.
 *
 *  This program 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 Library General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "dosbox.h"
#include "inout.h"
#include "vga.h"

#define attr(blah) vga.attr.blah

void write_p3c0(Bit32u port,Bit8u val) {
	if (!vga.internal.attrindex) {
		attr(index)=val & 0x1F;
		vga.internal.attrindex=true;
		/* 
			0-4  Address of data register to write to port 3C0h or read from port 3C1h
			If set screen output is enabled and the palette can not be modified,
			if clear screen output is disabled and the palette can be modified.
		*/
		return;
	} else {
		vga.internal.attrindex=false;
		switch (attr(index)) {
			/* Palette */
		case 0x00:		case 0x01:		case 0x02:		case 0x03:
		case 0x04:		case 0x05:		case 0x06:		case 0x07:
		case 0x08:		case 0x09:		case 0x0a:		case 0x0b:
		case 0x0c:		case 0x0d:		case 0x0e:		case 0x0f:
			val&=0x3f;
			attr(palette[attr(index)])=val;
			VGA_DAC_CombineColor(attr(index),val);
			/*
				0-5	Index into the 256 color DAC table. May be modified by 3C0h index
				10h and 14h.
			*/
			break;
		case 0x10: /* Mode Control Register */
			if (val != attr(mode_control)) {
				attr(mode_control)=val;
				vga.config.gfxmode=val&1;
				vga.config.vga_enabled=(val & 0x40)>0;
				VGA_FindSettings();
			}
			//TODO Monochrome mode
			//TODO 9 bit characters
			//TODO line wrapping split screen shit see bit 5
			//TODO index 14h weirdo dac switch bits
			/*
				0	Graphics mode if set, Alphanumeric mode else.
				1	Monochrome mode if set, color mode else.
				2	9-bit wide characters if set.
					The 9th bit of characters C0h-DFh will be the same as
					the 8th bit. Otherwise it will be the background color.
				3	If set Attribute bit 7 is blinking, else high intensity.
				5	If set the PEL panning register (3C0h index 13h) is temporarily set
					to 0 from when the line compare causes a wrap around until the next
					vertical retrace when the register is automatically reloaded with
					the old value, else the PEL panning register ignores line compares.
				6	If set pixels are 8 bits wide. Used in 256 color modes.
				7	If set bit 4-5 of the index into the DAC table are taken from port
					3C0h index 14h bit 0-1, else the bits in the palette register are
					used.
			*/
			if (val&128) {
				E_Exit("VGA:Special 16 colour DAC Shift");
			}
			break;
		case 0x11:	/* Overscan Color Register */
			attr(overscan_color)=val;
			/* 0-5  Color of screen border. Color is defined as in the palette registers. */
			break;
		case 0x12:	/* Color Plane Enable Register */
			/* Why disable colour planes? */
			attr(color_plane_enable)=val;
			/* 
				0	Bit plane 0 is enabled if set.
				1	Bit plane 1 is enabled if set.
				2	Bit plane 2 is enabled if set.
				3	Bit plane 3 is enabled if set.
				4-5	Video Status MUX. Diagnostics use only.
					Two attribute bits appear on bits 4 and 5 of the Input Status
					Register 1 (3dAh). 0: Bit 2/0, 1: Bit 5/4, 2: bit 3/1, 3: bit 7/6
			*/
			break;
		case 0x13:	/* Horizontal PEL Panning Register */
			attr(horizontal_pel_panning)=val & 0xF;
			vga.config.pel_panning=val & 0xF;
			/*
				0-3	Indicates number of pixels to shift the display left
					Value  9bit textmode   256color mode   Other modes
					0          1               0              0
					1          2              n/a             1
					2          3               1              2
					3          4              n/a             3
					4          5               2              4
					5          6              n/a             5
					6          7               3              6
					7          8              n/a             7
					8          0              n/a            n/a
			*/
			break;
		case 0x14:	/* Color Select Register */
			attr(color_select)=val;
			/*
				0-1	If 3C0h index 10h bit 7 is set these 2 bits are used as bits 4-5 of
					the index into the DAC table.
				2-3	These 2 bits are used as bit 6-7 of the index into the DAC table
					except in 256 color mode.
					Note: this register does not affect 256 color modes.
			*/
			if (val) LOG_DEBUG("VGA:ATTR:DAC index set to %d",val);
			break;
		default:
			LOG_ERROR("VGA:ATTR:Write to unkown Index %2X",attr(index));
			break;
		}
	}
}

Bit8u read_p3c1(Bit32u port) {
	vga.internal.attrindex=false;
	switch (attr(index)) {
			/* Palette */
	case 0x00:		case 0x01:		case 0x02:		case 0x03:
	case 0x04:		case 0x05:		case 0x06:		case 0x07:
	case 0x08:		case 0x09:		case 0x0a:		case 0x0b:
	case 0x0c:		case 0x0d:		case 0x0e:		case 0x0f:
		return attr(palette[attr(index)]);
	case 0x10: /* Mode Control Register */
		return attr(mode_control);
	case 0x11:	/* Overscan Color Register */
		return attr(overscan_color);
	case 0x12:	/* Color Plane Enable Register */
		return attr(color_plane_enable);
	case 0x13:	/* Horizontal PEL Panning Register */
		return attr(horizontal_pel_panning);
	case 0x14:	/* Color Select Register */
		return attr(color_select);
	default:
		LOG_ERROR("VGA:ATTR:Read from unkown Index %2X",attr(index));
	}
	return 0;
};






void VGA_SetupAttr(void) {
	IO_RegisterWriteHandler(0x3c0,write_p3c0,"VGA Attribute controller");
	IO_RegisterReadHandler(0x3c1,read_p3c1,"VGA Attribute Read");
}