dosbox-staging/src/hardware/vga.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 <stdlib.h>
#include <string.h>

#include "dosbox.h"
#include "video.h"
#include "pic.h"
#include "render.h"
#include "timer.h"
#include "vga.h"

VGA_Type vga;
Bit32u CGAWriteTable[256];
Bit32u ExpandTable[256];

Bit32u FillTable[16]={	
	0x00000000,0x000000ff,0x0000ff00,0x0000ffff,
	0x00ff0000,0x00ff00ff,0x00ffff00,0x00ffffff,
	0xff000000,0xff0000ff,0xff00ff00,0xff00ffff,
	0xffff0000,0xffff00ff,0xffffff00,0xffffffff
};

static PageEntry VGA_PageEntry;

void VGA_Render_GFX_4(Bit8u * * data);
void VGA_Render_GFX_16(Bit8u * * data);
void VGA_Render_GFX_256C(Bit8u * * data);
void VGA_Render_GFX_256U(Bit8u * * data);
void VGA_Render_TEXT_16(Bit8u * * data);

void VGA_FindSettings(void) {
	/* Sets up the correct memory handler from the vga.mode setting */
	MEMORY_ResetHandler(0xA0000/4096,128*1024/4096);
	VGA_PageEntry.type=MEMORY_HANDLER;
	/* Detect the kind of video mode this is */
	if (vga.config.gfxmode) {
		if (vga.config.vga_enabled) {
			if (vga.config.chained) {
			/* 256 color chained vga */
				vga.mode=GFX_256C;
				//Doesn't need a memory handler
			} else {
			/* 256 color unchained vga */
				vga.mode=GFX_256U;
				VGA_PageEntry.base=0xA0000;
				VGA_PageEntry.handler.read=VGA_NormalReadHandler;
				VGA_PageEntry.handler.write=VGA_GFX_256U_WriteHandler;
				MEMORY_SetupHandler(0xA0000/4096,16,&VGA_PageEntry);
			}
		} else if (vga.config.cga_enabled) {
			/* 4 color cga */
			//TODO Detect hercules modes, probably set them up in bios too
			vga.mode=GFX_4;
//			VGA_PageEntry.base=0xB8000;
//			VGA_PageEntry.handler.read=VGA_GFX_4_ReadHandler;
//			VGA_PageEntry.handler.write=VGA_GFX_4_WriteHandler;
//			MEMORY_SetupHandler(0xB8000/4096,8,&VGA_PageEntry);
		} else {
			/* 16 color ega */
			vga.mode=GFX_16;
			VGA_PageEntry.base=0xA0000;
			VGA_PageEntry.handler.read=VGA_NormalReadHandler;
			VGA_PageEntry.handler.write=VGA_GFX_16_WriteHandler;
			MEMORY_SetupHandler(0xA0000/4096,16,&VGA_PageEntry);
		}
	} else {
		vga.mode=TEXT_16;
	}
	VGA_StartResize();
}

static void VGA_DoResize(void) {
	vga.draw.resizing=false;
	Bitu width,height,pitch;
	RENDER_Handler * renderer;

	height=vga.config.vdisplayend+1;
	if (vga.config.vline_height>0) {
		height/=(vga.config.vline_height+1);
	}
	if (vga.config.vline_double) height>>=1;
	width=vga.config.hdisplayend;
	switch (vga.mode) {
	case GFX_256C:
		renderer=&VGA_Render_GFX_256C;
		width<<=2;
		pitch=vga.config.scan_len*8;
		break;
	case GFX_256U:
		width<<=2;
		pitch=vga.config.scan_len*8;
		renderer=&VGA_Render_GFX_256U;
		break;
	case GFX_16:
		width<<=3;
		pitch=vga.config.scan_len*16;
		renderer=&VGA_Render_GFX_16;
		break;
	case GFX_4:
		width<<=3;
		height<<=1;
		pitch=width;
		renderer=&VGA_Render_GFX_4;
		break;
	case TEXT_16:
		/* probably a 16-color text mode, got to detect mono mode somehow */
		width<<=3;		/* 8 bit wide text font */
		height<<=4;		/* 16 bit font height */
		if (width>640) width=640;
		if (height>480) height=480;
		pitch=width;
		renderer=&VGA_Render_TEXT_16;
	};

	vga.draw.width=width;
	vga.draw.height=height;
	RENDER_SetSize(width,height,8,pitch,((float)width/(float)height),0,renderer);

};

void VGA_StartResize(void) {
	if (!vga.draw.resizing) {
		vga.draw.resizing=true;
		/* Start a resize after 50 ms */
		TIMER_RegisterDelayHandler(VGA_DoResize,50);
	}
}




void VGA_Init() {
	vga.draw.resizing=false;
	VGA_SetupMemory();
	VGA_SetupMisc();
	VGA_SetupDAC();
	VGA_SetupCRTC();
	VGA_SetupGFX();
	VGA_SetupSEQ();
	VGA_SetupAttr();
/* Generate tables */
	Bit32u i;
	for (i=0;i<256;i++) {
		ExpandTable[i]=i | (i << 8)| (i <<16) | (i << 24);
		CGAWriteTable[i]=((i>>6)&3) | (((i>>4)&3) << 8)| (((i>>2)&3) <<16) | (((i>>0)&3) << 24);
	}
}