/*
 * 86Box	A hypervisor and IBM PC system emulator that specializes in
 *		running old operating systems and software designed for IBM
 *		PC systems and compatibles from 1981 through fairly recent
 *		system designs based on the PCI bus.
 *
 *		This file is part of the 86Box distribution.
 *
 *		Generic SVGA handling.
 *
 *		This is intended to be used by another SVGA driver,
 *		and not as a card in it's own right.
 *
 * Version:	@(#)vid_svga.c	1.0.20	2018/02/09
 *
 * Authors:	Sarah Walker, <http://pcem-emulator.co.uk/>
 *		Miran Grca, <mgrca8@gmail.com>
 *
 *		Copyright 2008-2018 Sarah Walker.
 *		Copyright 2016-2018 Miran Grca.
 */
#include <inttypes.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <wchar.h>
#include "../86box.h"
#include "../cpu/cpu.h"
#include "../machine/machine.h"
#include "../io.h"
#include "../pit.h"
#include "../mem.h"
#include "../rom.h"
#include "../timer.h"
#include "video.h"
#include "vid_svga.h"
#include "vid_svga_render.h"


#define svga_output 0

void svga_doblit(int y1, int y2, int wx, int wy, svga_t *svga);

extern uint8_t edatlookup[4][4];

uint8_t svga_rotate[8][256];

/*Primary SVGA device. As multiple video cards are not yet supported this is the
  only SVGA device.*/
static svga_t *svga_pri;

svga_t *svga_get_pri()
{
        return svga_pri;
}
void svga_set_override(svga_t *svga, int val)
{
        if (svga->override && !val)
                svga->fullchange = changeframecount;
        svga->override = val;
}

void svga_out(uint16_t addr, uint8_t val, void *p)
{
        svga_t *svga = (svga_t *)p;
        int c;
        uint8_t o;
        switch (addr)
        {
                case 0x3C0:
		case 0x3C1:
                if (!svga->attrff)
                {
                        svga->attraddr = val & 31;
                        if ((val & 0x20) != svga->attr_palette_enable)
                        {
                                svga->fullchange = 3;
                                svga->attr_palette_enable = val & 0x20;
                                svga_recalctimings(svga);
                        }
                }
                else
                {
			o = svga->attrregs[svga->attraddr & 31];
                        svga->attrregs[svga->attraddr & 31] = val;
                        if (svga->attraddr < 16) 
                                svga->fullchange = changeframecount;
                        if (svga->attraddr == 0x10 || svga->attraddr == 0x14 || svga->attraddr < 0x10)
                        {
                                for (c = 0; c < 16; c++)
                                {
                                        if (svga->attrregs[0x10] & 0x80) svga->egapal[c] = (svga->attrregs[c] &  0xf) | ((svga->attrregs[0x14] & 0xf) << 4);
                                        else                             svga->egapal[c] = (svga->attrregs[c] & 0x3f) | ((svga->attrregs[0x14] & 0xc) << 4);
                                }
                        }
			/* Recalculate timings on change of attribute register 0x11 (overscan border color) too. */
                        if ((svga->attraddr == 0x10) || (svga->attraddr == 0x11))
                                if (o != val)  svga_recalctimings(svga);
                        if (svga->attraddr == 0x12)
                        {
                                if ((val & 0xf) != svga->plane_mask)
                                        svga->fullchange = changeframecount;
                                svga->plane_mask = val & 0xf;
                        }
                }
                svga->attrff ^= 1;
                break;
                case 0x3C2:
                svga->miscout = val;
                svga->vidclock = val & 4;
                if (val & 1)
                {
                        io_removehandler(0x03a0, 0x0020, svga->video_in, NULL, NULL, svga->video_out, NULL, NULL, svga->p);
                }
                else
                {
                        io_sethandler(0x03a0, 0x0020, svga->video_in, NULL, NULL, svga->video_out, NULL, NULL, svga->p);
                }
                svga_recalctimings(svga);
                break;
                case 0x3C4: 
                svga->seqaddr = val; 
                break;
                case 0x3C5:
                if (svga->seqaddr > 0xf) return;
                o = svga->seqregs[svga->seqaddr & 0xf];
                svga->seqregs[svga->seqaddr & 0xf] = val;
                if (o != val && (svga->seqaddr & 0xf) == 1)
                        svga_recalctimings(svga);
                switch (svga->seqaddr & 0xf)
                {
                        case 1: 
                        if (svga->scrblank && !(val & 0x20)) 
                                svga->fullchange = 3; 
                        svga->scrblank = (svga->scrblank & ~0x20) | (val & 0x20); 
                        svga_recalctimings(svga);
                        break;
                        case 2: 
                        svga->writemask = val & 0xf; 
                        break;
                        case 3:
                        svga->charsetb = (((val >> 2) & 3) * 0x10000) + 2;
                        svga->charseta = ((val & 3)  * 0x10000) + 2;
                        if (val & 0x10)
                                svga->charseta += 0x8000;
                        if (val & 0x20)
                                svga->charsetb += 0x8000;
                        break;
                        case 4: 
                        svga->chain2_write = !(val & 4);
                        svga->chain4 = val & 8;
                        svga->fast = (svga->gdcreg[8] == 0xff && !(svga->gdcreg[3] & 0x18) && !svga->gdcreg[1]) && svga->chain4;
                        break;
                }
                break;
                case 0x3c6: 
                svga->dac_mask = val; 
                break;
                case 0x3C7: 
                svga->dac_read = val; 
                svga->dac_pos = 0; 
                break;
                case 0x3C8: 
                svga->dac_write = val; 
                svga->dac_read = val - 1; 
                svga->dac_pos = 0; 
                break;
                case 0x3C9:
                svga->dac_status = 0;
                svga->fullchange = changeframecount;
                switch (svga->dac_pos)
                {
                        case 0: 
                        svga->dac_r = val;
                        svga->dac_pos++; 
                        break;
                        case 1: 
                        svga->dac_g = val;
                        svga->dac_pos++; 
                        break;
                        case 2: 
                        svga->vgapal[svga->dac_write].r = svga->dac_r;
                        svga->vgapal[svga->dac_write].g = svga->dac_g;
                        svga->vgapal[svga->dac_write].b = val; 
                        if (svga->ramdac_type == RAMDAC_8BIT)
                                svga->pallook[svga->dac_write] = makecol32(svga->vgapal[svga->dac_write].r, svga->vgapal[svga->dac_write].g, svga->vgapal[svga->dac_write].b);
                        else
                               	svga->pallook[svga->dac_write] = makecol32(video_6to8[svga->vgapal[svga->dac_write].r & 0x3f], video_6to8[svga->vgapal[svga->dac_write].g & 0x3f], video_6to8[svga->vgapal[svga->dac_write].b & 0x3f]);
                        svga->dac_pos = 0; 
                        svga->dac_write = (svga->dac_write + 1) & 255; 
                        break;
                }
                break;
                case 0x3CE: 
                svga->gdcaddr = val; 
                break;
                case 0x3CF:
                o = svga->gdcreg[svga->gdcaddr & 15];
                switch (svga->gdcaddr & 15)
                {
                        case 2: svga->colourcompare=val; break;
                        case 4: svga->readplane=val&3; break;
                        case 5:
                        svga->writemode = val & 3;
                        svga->readmode = val & 8;
                        svga->chain2_read = val & 0x10;
                        break;
                        case 6:
                        if ((svga->gdcreg[6] & 0xc) != (val & 0xc))
                        {
                                switch (val&0xC)
                                {
                                        case 0x0: /*128k at A0000*/
                                        mem_mapping_set_addr(&svga->mapping, 0xa0000, 0x20000);
                                        svga->banked_mask = 0xffff;
                                        break;
                                        case 0x4: /*64k at A0000*/
                                        mem_mapping_set_addr(&svga->mapping, 0xa0000, 0x10000);
                                        svga->banked_mask = 0xffff;
                                        break;
                                        case 0x8: /*32k at B0000*/
                                        mem_mapping_set_addr(&svga->mapping, 0xb0000, 0x08000);
                                        svga->banked_mask = 0x7fff;
                                        break;
                                        case 0xC: /*32k at B8000*/
                                        mem_mapping_set_addr(&svga->mapping, 0xb8000, 0x08000);
                                        svga->banked_mask = 0x7fff;
                                        break;
                                }
                        }
                        break;
                        case 7: svga->colournocare=val; break;
                }
                svga->gdcreg[svga->gdcaddr & 15] = val;                
                svga->fast = (svga->gdcreg[8] == 0xff && !(svga->gdcreg[3] & 0x18) && !svga->gdcreg[1]) && svga->chain4;
                if (((svga->gdcaddr & 15) == 5  && (val ^ o) & 0x70) || ((svga->gdcaddr & 15) == 6 && (val ^ o) & 1))
                        svga_recalctimings(svga);
                break;
        }
}

uint8_t svga_in(uint16_t addr, void *p)
{
        svga_t *svga = (svga_t *)p;
        uint8_t temp;
        switch (addr)
        {
                case 0x3C0: 
                return svga->attraddr | svga->attr_palette_enable;
                case 0x3C1: 
                return svga->attrregs[svga->attraddr];
                case 0x3c2:
                if ((svga->vgapal[0].r + svga->vgapal[0].g + svga->vgapal[0].b) >= 0x4e)
                        temp = 0;
                else
                        temp = 0x10;
                return temp;
                case 0x3C4: 
                return svga->seqaddr;
                case 0x3C5:
                return svga->seqregs[svga->seqaddr & 0xF];
                case 0x3c6: return svga->dac_mask;
                case 0x3c7: return svga->dac_status;
                case 0x3c8: return svga->dac_write;
                case 0x3c9:
                svga->dac_status = 3;
                switch (svga->dac_pos)
                {
                        case 0: 
                        svga->dac_pos++; 
                        if (svga->ramdac_type == RAMDAC_8BIT)
                                return svga->vgapal[svga->dac_read].r;
                        return svga->vgapal[svga->dac_read].r & 0x3f;
                        case 1: 
                        svga->dac_pos++; 
                        if (svga->ramdac_type == RAMDAC_8BIT)
                                return svga->vgapal[svga->dac_read].g;
                        return svga->vgapal[svga->dac_read].g & 0x3f;
                        case 2: 
                        svga->dac_pos=0; 
                        svga->dac_read = (svga->dac_read + 1) & 255; 
                        if (svga->ramdac_type == RAMDAC_8BIT)
                                return svga->vgapal[(svga->dac_read - 1) & 255].b;
                        return svga->vgapal[(svga->dac_read - 1) & 255].b & 0x3f;
                }
                break;
                case 0x3CC: 
                return svga->miscout;
                case 0x3CE: 
                return svga->gdcaddr;
                case 0x3CF:
		/* The spec says GDC addresses 0xF8 to 0xFB return the latch. */
		if (svga->gdcaddr == 0xF8)  return svga->la;
		if (svga->gdcaddr == 0xF9)  return svga->lb;
		if (svga->gdcaddr == 0xFA)  return svga->lc;
		if (svga->gdcaddr == 0xFB)  return svga->ld;
                return svga->gdcreg[svga->gdcaddr & 0xf];
                case 0x3DA:
                svga->attrff = 0;
                if (svga->cgastat & 0x01)
                        svga->cgastat &= ~0x30;
                else
                        svga->cgastat ^= 0x30;
                return svga->cgastat;
        }
        return 0xFF;
}

void svga_set_ramdac_type(svga_t *svga, int type)
{
        int c;
        
        if (svga->ramdac_type != type)
        {
                svga->ramdac_type = type;
                        
                for (c = 0; c < 256; c++)
                {
                        if (svga->ramdac_type == RAMDAC_8BIT)
                                svga->pallook[c] = makecol32(svga->vgapal[c].r, svga->vgapal[c].g, svga->vgapal[c].b);
                        else
                                svga->pallook[c] = makecol32((svga->vgapal[c].r & 0x3f) * 4, (svga->vgapal[c].g & 0x3f) * 4, (svga->vgapal[c].b & 0x3f) * 4); 
                }
        }
}

void svga_recalctimings(svga_t *svga)
{
        double crtcconst;
        double _dispontime, _dispofftime, disptime;

        svga->vtotal = svga->crtc[6];
        svga->dispend = svga->crtc[0x12];
        svga->vsyncstart = svga->crtc[0x10];
        svga->split = svga->crtc[0x18];
        svga->vblankstart = svga->crtc[0x15];

        if (svga->crtc[7] & 1)  svga->vtotal |= 0x100;
        if (svga->crtc[7] & 32) svga->vtotal |= 0x200;
        svga->vtotal += 2;

        if (svga->crtc[7] & 2)  svga->dispend |= 0x100;
        if (svga->crtc[7] & 64) svga->dispend |= 0x200;
        svga->dispend++;

        if (svga->crtc[7] & 4)   svga->vsyncstart |= 0x100;
        if (svga->crtc[7] & 128) svga->vsyncstart |= 0x200;
        svga->vsyncstart++;

        if (svga->crtc[7] & 0x10) svga->split|=0x100;
        if (svga->crtc[9] & 0x40) svga->split|=0x200;
        svga->split++;
        
        if (svga->crtc[7] & 0x08) svga->vblankstart |= 0x100;
        if (svga->crtc[9] & 0x20) svga->vblankstart |= 0x200;
        svga->vblankstart++;
        
        svga->hdisp = svga->crtc[1];
        svga->hdisp++;

        svga->htotal = svga->crtc[0];
        svga->htotal += 6; /*+6 is required for Tyrian*/

        svga->rowoffset = svga->crtc[0x13];

        svga->clock = (svga->vidclock) ? VGACONST2 : VGACONST1;
        
        svga->lowres = svga->attrregs[0x10] & 0x40;
        
        svga->interlace = 0;
        
        svga->ma_latch = (svga->crtc[0xc] << 8) | svga->crtc[0xd];

        svga->hdisp_time = svga->hdisp;
        svga->render = svga_render_blank;
        if (!svga->scrblank && svga->attr_palette_enable) {
                if (!(svga->gdcreg[6] & 1)) /*Text mode*/ {
                        if (svga->seqregs[1] & 8) /*40 column*/ {
                                svga->render = svga_render_text_40;
                                svga->hdisp *= (svga->seqregs[1] & 1) ? 16 : 18;
                        } else {
                                svga->render = svga_render_text_80;
                                svga->hdisp *= (svga->seqregs[1] & 1) ? 8 : 9;
                        }
                        svga->hdisp_old = svga->hdisp;
                } else {
                        svga->hdisp *= (svga->seqregs[1] & 8) ? 16 : 8;
                        svga->hdisp_old = svga->hdisp;                        
                        
                        switch (svga->gdcreg[5] & 0x60) {
                                case 0x00: /*16 colours*/
                                if (svga->seqregs[1] & 8) /*Low res (320)*/
                                        svga->render = svga_render_4bpp_lowres;
                                else
                                        svga->render = svga_render_4bpp_highres;
                                break;
                                case 0x20: /*4 colours*/
                                if (svga->seqregs[1] & 8) /*Low res (320)*/
                                        svga->render = svga_render_2bpp_lowres;
                                else
                                        svga->render = svga_render_2bpp_highres;
                                break;
                                case 0x40: case 0x60: /*256+ colours*/
                                switch (svga->bpp) {
                                        case 8:
                                        if (svga->lowres)
                                                svga->render = svga_render_8bpp_lowres;
                                        else
                                                svga->render = svga_render_8bpp_highres;
                                        break;
                                        case 15:
                                        if (svga->lowres)
                                                svga->render = svga_render_15bpp_lowres;
                                        else
                                                svga->render = svga_render_15bpp_highres;
                                        break;
                                        case 16:
                                        if (svga->lowres)
                                                svga->render = svga_render_16bpp_lowres;
                                        else
                                                svga->render = svga_render_16bpp_highres;
                                        break;
                                        case 24:
                                        if (svga->lowres)
                                                svga->render = svga_render_24bpp_lowres;
                                        else
                                                svga->render = svga_render_24bpp_highres;
                                        break;
                                        case 32:
                                        if (svga->lowres)
                                                svga->render = svga_render_32bpp_lowres;
                                        else
                                                svga->render = svga_render_32bpp_highres;
                                        break;
                                }
                                break;
                        }
                }
        }        

        svga->linedbl = svga->crtc[9] & 0x80;
        svga->rowcount = svga->crtc[9] & 31;
	if (enable_overscan) {
		overscan_y = (svga->rowcount + 1) << 1;
		if (svga->seqregs[1] & 8) /*Low res (320)*/
			overscan_y <<= 1;
		if (overscan_y < 16)
			overscan_y = 16;
	}
        if (svga->recalctimings_ex) 
                svga->recalctimings_ex(svga);

        if (svga->vblankstart < svga->dispend)
                svga->dispend = svga->vblankstart;

        crtcconst = (svga->seqregs[1] & 1) ? (svga->clock * 8.0) : (svga->clock * 9.0);

        disptime  = svga->htotal;
        _dispontime = svga->hdisp_time;
        
        if (svga->seqregs[1] & 8) { disptime *= 2; _dispontime *= 2; }
        _dispofftime = disptime - _dispontime;
        _dispontime *= crtcconst;
        _dispofftime *= crtcconst;

	svga->dispontime = (int)(_dispontime * (1 << TIMER_SHIFT));
	svga->dispofftime = (int)(_dispofftime * (1 << TIMER_SHIFT));
}

extern int cyc_total;
void svga_poll(void *p)
{
        svga_t *svga = (svga_t *)p;
        int x;

        if (!svga->linepos) {
                if (svga->displine == svga->hwcursor_latch.y && svga->hwcursor_latch.ena) {
                        svga->hwcursor_on = 64 - svga->hwcursor_latch.yoff;
                        svga->hwcursor_oddeven = 0;
                }

                if (svga->displine == svga->hwcursor_latch.y+1 && svga->hwcursor_latch.ena && svga->interlace) {
                        svga->hwcursor_on = 64 - svga->hwcursor_latch.yoff;
                        svga->hwcursor_oddeven = 1;
                }

                if (svga->displine == svga->overlay_latch.y && svga->overlay_latch.ena) {
                        svga->overlay_on = svga->overlay_latch.ysize - svga->overlay_latch.yoff;
                        svga->overlay_oddeven = 0;
                }
                if (svga->displine == svga->overlay_latch.y+1 && svga->overlay_latch.ena && svga->interlace) {
                        svga->overlay_on = svga->overlay_latch.ysize - svga->overlay_latch.yoff;
                        svga->overlay_oddeven = 1;
                }

                svga->vidtime += svga->dispofftime;
                svga->cgastat |= 1;
                svga->linepos = 1;

                if (svga->dispon) {
                        svga->hdisp_on=1;
                        
                        svga->ma &= svga->vram_display_mask;
                        if (svga->firstline == 2000) {
                                svga->firstline = svga->displine;
                                video_wait_for_buffer();
                        }
                        
                        if (svga->hwcursor_on || svga->overlay_on)
                                svga->changedvram[svga->ma >> 12] = svga->changedvram[(svga->ma >> 12) + 1] = svga->interlace ? 3 : 2;;
                      
                        if (!svga->override)
                                svga->render(svga);
                        
                        if (svga->overlay_on) {
                                if (!svga->override)
                                        svga->overlay_draw(svga, svga->displine);
                                svga->overlay_on--;
                                if (svga->overlay_on && svga->interlace)
                                        svga->overlay_on--;
                        }

                        if (svga->hwcursor_on) {
                                if (!svga->override)
                                        svga->hwcursor_draw(svga, svga->displine);
                                svga->hwcursor_on--;
                                if (svga->hwcursor_on && svga->interlace)
                                        svga->hwcursor_on--;
                        }

                        if (svga->lastline < svga->displine) 
                                svga->lastline = svga->displine;
                }

                svga->displine++;
                if (svga->interlace) 
                        svga->displine++;
                if ((svga->cgastat & 8) && ((svga->displine & 15) == (svga->crtc[0x11] & 15)) && svga->vslines)
                        svga->cgastat &= ~8;
                svga->vslines++;
                if (svga->displine > 1500)
                        svga->displine = 0;
        } else {
                svga->vidtime += svga->dispontime;

                if (svga->dispon) 
                        svga->cgastat &= ~1;
                svga->hdisp_on = 0;
                
                svga->linepos = 0;
                if (svga->sc == (svga->crtc[11] & 31)) 
                        svga->con = 0;
                if (svga->dispon) {
                        if (svga->linedbl && !svga->linecountff) {
                                svga->linecountff = 1;
                                svga->ma = svga->maback;
                        } else if (svga->sc == svga->rowcount) {
                                svga->linecountff = 0;
                                svga->sc = 0;

                                svga->maback += (svga->rowoffset << 3);
                                if (svga->interlace)
                                        svga->maback += (svga->rowoffset << 3);
                                svga->maback &= svga->vram_display_mask;
                                svga->ma = svga->maback;
                        } else {
                                svga->linecountff = 0;
                                svga->sc++;
                                svga->sc &= 31;
                                svga->ma = svga->maback;
                        }
                }
                svga->vc++;
                svga->vc &= 2047;

                if (svga->vc == svga->split) {
                        svga->ma = svga->maback = 0;
                        if (svga->attrregs[0x10] & 0x20) 
                                svga->scrollcache = 0;
                }
                if (svga->vc == svga->dispend) {
                        if (svga->vblank_start)
                                svga->vblank_start(svga);
                        svga->dispon=0;
                        if (svga->crtc[10] & 0x20) svga->cursoron = 0;
                        else                       svga->cursoron = svga->blink & 16;
                        if (!(svga->gdcreg[6] & 1) && !(svga->blink & 15)) 
                                svga->fullchange = 2;
                        svga->blink++;

                        for (x = 0; x < ((svga->vram_mask+1) >> 12); x++) {
                                if (svga->changedvram[x]) 
                                        svga->changedvram[x]--;
                        }
                        if (svga->fullchange) 
                                svga->fullchange--;
                }
                if (svga->vc == svga->vsyncstart) {
                        int wx, wy;
                        svga->dispon=0;
                        svga->cgastat |= 8;
                        x = svga->hdisp;

                        if (svga->interlace && !svga->oddeven) svga->lastline++;
                        if (svga->interlace &&  svga->oddeven) svga->firstline--;

                        wx = x;
                        wy = svga->lastline - svga->firstline;

                        if (!svga->override)
                                svga_doblit(svga->firstline_draw, svga->lastline_draw + 1, wx, wy, svga);

                        svga->firstline = 2000;
                        svga->lastline = 0;
                        
                        svga->firstline_draw = 2000;
                        svga->lastline_draw = 0;
                        
                        svga->oddeven ^= 1;

                        changeframecount = svga->interlace ? 3 : 2;
                        svga->vslines = 0;
                        
                        if (svga->interlace && svga->oddeven) svga->ma = svga->maback = svga->ma_latch + (svga->rowoffset << 1);
                        else                                  svga->ma = svga->maback = svga->ma_latch;
                        svga->ca = (svga->crtc[0xe] << 8) | svga->crtc[0xf];

                        svga->ma <<= 2;
                        svga->maback <<= 2;
                        svga->ca <<= 2;

                        svga->video_res_x = wx;
                        svga->video_res_y = wy + 1;
                        if (!(svga->gdcreg[6] & 1)) { /*Text mode*/
                                svga->video_res_x /= (svga->seqregs[1] & 1) ? 8 : 9;
                                svga->video_res_y /= (svga->crtc[9] & 31) + 1;
                                svga->video_bpp = 0;
                        } else {
                                if (svga->crtc[9] & 0x80)
                                   svga->video_res_y /= 2;
                                if (!(svga->crtc[0x17] & 1))
                                   svga->video_res_y *= 2;
                                svga->video_res_y /= (svga->crtc[9] & 31) + 1;                                   
                                if (svga->lowres)
                                   svga->video_res_x /= 2;

                                switch (svga->gdcreg[5] & 0x60) {
                                        case 0x00:            svga->video_bpp = 4;   break;
                                        case 0x20:            svga->video_bpp = 2;   break;
                                        case 0x40: case 0x60: svga->video_bpp = svga->bpp; break;
                                }
                        }
                }
                if (svga->vc == svga->vtotal) {
                        svga->vc = 0;
                        svga->sc = svga->crtc[8] & 0x1f;
                        svga->dispon = 1;
                        svga->displine = (svga->interlace && svga->oddeven) ? 1 : 0;
                        svga->scrollcache = svga->attrregs[0x13] & 7;
                        svga->linecountff = 0;
                        
                        svga->hwcursor_on = 0;
                        svga->hwcursor_latch = svga->hwcursor;

                        svga->overlay_on = 0;
                        svga->overlay_latch = svga->overlay;
                }
                if (svga->sc == (svga->crtc[10] & 31)) 
                        svga->con = 1;
        }
}

int svga_init(svga_t *svga, void *p, int memsize, 
               void (*recalctimings_ex)(struct svga_t *svga),
               uint8_t (*video_in) (uint16_t addr, void *p),
               void    (*video_out)(uint16_t addr, uint8_t val, void *p),
               void (*hwcursor_draw)(struct svga_t *svga, int displine),
               void (*overlay_draw)(struct svga_t *svga, int displine))
{
        int c, d, e;
        
        svga->p = p;
        
        for (c = 0; c < 256; c++) {
                e = c;
                for (d = 0; d < 8; d++) {
                        svga_rotate[d][c] = e;
                        e = (e >> 1) | ((e & 1) ? 0x80 : 0);
                }
        }
        svga->readmode = 0;

	svga->attrregs[0x11] = 0;

	overscan_x = 16;
	overscan_y = 32;

        svga->crtc[0] = 63;
        svga->crtc[6] = 255;
        svga->dispontime = 1000 * (1 << TIMER_SHIFT);
        svga->dispofftime = 1000 * (1 << TIMER_SHIFT);        
        svga->bpp = 8;
        svga->vram = malloc(memsize);
        svga->vram_max = memsize;
        svga->vram_display_mask = memsize - 1;
        svga->vram_mask = memsize - 1;
        svga->decode_mask = 0x7fffff;
        svga->changedvram = malloc(/*(memsize >> 12) << 1*/0x800000 >> 12);
        svga->recalctimings_ex = recalctimings_ex;
        svga->video_in  = video_in;
        svga->video_out = video_out;
        svga->hwcursor_draw = hwcursor_draw;
        svga->overlay_draw = overlay_draw;

        mem_mapping_add(&svga->mapping, 0xa0000, 0x20000, svga_read, svga_readw, svga_readl, svga_write, svga_writew, svga_writel, NULL, MEM_MAPPING_EXTERNAL, svga);

        timer_add(svga_poll, &svga->vidtime, TIMER_ALWAYS_ENABLED, svga);
        
        svga_pri = svga;
        
        svga->ramdac_type = RAMDAC_6BIT;
        
        return 0;
}

void svga_close(svga_t *svga)
{
        free(svga->changedvram);
        free(svga->vram);
        
        svga_pri = NULL;
}

void svga_write(uint32_t addr, uint8_t val, void *p)
{
        svga_t *svga = (svga_t *)p;
        uint8_t vala, valb, valc, vald, wm = svga->writemask;
        int writemask2 = svga->writemask;

        egawrites++;

        cycles -= video_timing_write_b;
        cycles_lost += video_timing_write_b;

        if (svga_output) pclog("Writeega %06X   ",addr);
        addr &= svga->banked_mask;
        addr += svga->write_bank;

        if (!(svga->gdcreg[6] & 1)) svga->fullchange=2;
        if (svga->chain4 || svga->fb_only)
        {
                writemask2=1<<(addr&3);
                addr&=~3;
        }
        else if (svga->chain2_write)
        {
                writemask2 &= ~0xa;
                if (addr & 1)
                        writemask2 <<= 1;
                addr &= ~1;
                addr <<= 2;
        }
        else
        {
                addr<<=2;
        }
        addr &= svga->decode_mask;

        if (addr >= svga->vram_max)
                return;
        
        addr &= svga->vram_mask;

        if (svga_output) pclog("%08X (%i, %i) %02X %i %i %i %02X\n", addr, addr & 1023, addr >> 10, val, writemask2, svga->writemode, svga->chain4, svga->gdcreg[8]);
        svga->changedvram[addr >> 12] = changeframecount;

        switch (svga->writemode)
        {
                case 1:
                if (writemask2 & 1) svga->vram[addr]       = svga->la;
                if (writemask2 & 2) svga->vram[addr | 0x1] = svga->lb;
                if (writemask2 & 4) svga->vram[addr | 0x2] = svga->lc;
                if (writemask2 & 8) svga->vram[addr | 0x3] = svga->ld;
                break;
                case 0:
                if (svga->gdcreg[3] & 7) 
                        val = svga_rotate[svga->gdcreg[3] & 7][val];
                if (svga->gdcreg[8] == 0xff && !(svga->gdcreg[3] & 0x18) && (!svga->gdcreg[1] || svga->set_reset_disabled))
                {
                        if (writemask2 & 1) svga->vram[addr]       = val;
                        if (writemask2 & 2) svga->vram[addr | 0x1] = val;
                        if (writemask2 & 4) svga->vram[addr | 0x2] = val;
                        if (writemask2 & 8) svga->vram[addr | 0x3] = val;
                }
                else
                {
                        if (svga->gdcreg[1] & 1) vala = (svga->gdcreg[0] & 1) ? 0xff : 0;
                        else                     vala = val;
                        if (svga->gdcreg[1] & 2) valb = (svga->gdcreg[0] & 2) ? 0xff : 0;
                        else                     valb = val;
                        if (svga->gdcreg[1] & 4) valc = (svga->gdcreg[0] & 4) ? 0xff : 0;
                        else                     valc = val;
                        if (svga->gdcreg[1] & 8) vald = (svga->gdcreg[0] & 8) ? 0xff : 0;
                        else                     vald = val;

                        switch (svga->gdcreg[3] & 0x18)
                        {
                                case 0: /*Set*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | (svga->la & ~svga->gdcreg[8]);
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | (svga->lb & ~svga->gdcreg[8]);
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | (svga->lc & ~svga->gdcreg[8]);
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | (svga->ld & ~svga->gdcreg[8]);
                                break;
                                case 8: /*AND*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala | ~svga->gdcreg[8]) & svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb | ~svga->gdcreg[8]) & svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc | ~svga->gdcreg[8]) & svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald | ~svga->gdcreg[8]) & svga->ld;
                                break;
                                case 0x10: /*OR*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | svga->ld;
                                break;
                                case 0x18: /*XOR*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) ^ svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) ^ svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) ^ svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) ^ svga->ld;
                                break;
                        }
//                        pclog("- %02X %02X %02X %02X   %08X\n",vram[addr],vram[addr|0x1],vram[addr|0x2],vram[addr|0x3],addr);
                }
                break;
                case 2:
                if (!(svga->gdcreg[3] & 0x18) && (!svga->gdcreg[1] || svga->set_reset_disabled))
                {
                        if (writemask2 & 1) svga->vram[addr]       = (((val & 1) ? 0xff : 0) & svga->gdcreg[8]) | (svga->la & ~svga->gdcreg[8]);
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (((val & 2) ? 0xff : 0) & svga->gdcreg[8]) | (svga->lb & ~svga->gdcreg[8]);
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (((val & 4) ? 0xff : 0) & svga->gdcreg[8]) | (svga->lc & ~svga->gdcreg[8]);
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (((val & 8) ? 0xff : 0) & svga->gdcreg[8]) | (svga->ld & ~svga->gdcreg[8]);
                }
                else
                {
                        vala = ((val & 1) ? 0xff : 0);
                        valb = ((val & 2) ? 0xff : 0);
                        valc = ((val & 4) ? 0xff : 0);
                        vald = ((val & 8) ? 0xff : 0);
                        switch (svga->gdcreg[3] & 0x18)
                        {
                                case 0: /*Set*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | (svga->la & ~svga->gdcreg[8]);
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | (svga->lb & ~svga->gdcreg[8]);
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | (svga->lc & ~svga->gdcreg[8]);
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | (svga->ld & ~svga->gdcreg[8]);
                                break;
                                case 8: /*AND*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala | ~svga->gdcreg[8]) & svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb | ~svga->gdcreg[8]) & svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc | ~svga->gdcreg[8]) & svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald | ~svga->gdcreg[8]) & svga->ld;
                                break;
                                case 0x10: /*OR*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | svga->ld;
                                break;
                                case 0x18: /*XOR*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) ^ svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) ^ svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) ^ svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) ^ svga->ld;
                                break;
                        }
                }
                break;
                case 3:
                if (svga->gdcreg[3] & 7) 
                        val = svga_rotate[svga->gdcreg[3] & 7][val];
                wm = svga->gdcreg[8];
                svga->gdcreg[8] &= val;

                vala = (svga->gdcreg[0] & 1) ? 0xff : 0;
                valb = (svga->gdcreg[0] & 2) ? 0xff : 0;
                valc = (svga->gdcreg[0] & 4) ? 0xff : 0;
                vald = (svga->gdcreg[0] & 8) ? 0xff : 0;
                switch (svga->gdcreg[3] & 0x18)
                {
                        case 0: /*Set*/
                        if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | (svga->la & ~svga->gdcreg[8]);
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | (svga->lb & ~svga->gdcreg[8]);
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | (svga->lc & ~svga->gdcreg[8]);
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | (svga->ld & ~svga->gdcreg[8]);
                        break;
                        case 8: /*AND*/
                        if (writemask2 & 1) svga->vram[addr]       = (vala | ~svga->gdcreg[8]) & svga->la;
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (valb | ~svga->gdcreg[8]) & svga->lb;
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (valc | ~svga->gdcreg[8]) & svga->lc;
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (vald | ~svga->gdcreg[8]) & svga->ld;
                        break;
                        case 0x10: /*OR*/
                        if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | svga->la;
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | svga->lb;
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | svga->lc;
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | svga->ld;
                        break;
                        case 0x18: /*XOR*/
                        if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) ^ svga->la;
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) ^ svga->lb;
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) ^ svga->lc;
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) ^ svga->ld;
                        break;
                }
                svga->gdcreg[8] = wm;
                break;
        }
}

uint8_t svga_read(uint32_t addr, void *p)
{
        svga_t *svga = (svga_t *)p;
        uint8_t temp, temp2, temp3, temp4;
        uint32_t latch_addr;
        int readplane = svga->readplane;
        
        cycles -= video_timing_read_b;
        cycles_lost += video_timing_read_b;
        
        egareads++;
//        pclog("Readega %06X   ",addr);

        addr &= svga->banked_mask;
        addr += svga->read_bank;
                
        latch_addr = (addr << 2) & svga->decode_mask;
        
//        pclog("%05X %i %04X:%04X %02X %02X %i\n",addr,svga->chain4,CS,pc, vram[addr & 0x7fffff], vram[(addr << 2) & 0x7fffff], svga->readmode);
//        pclog("%i\n", svga->readmode);
        if (svga->chain4 || svga->fb_only) 
        { 
                addr &= svga->decode_mask;
                if (addr >= svga->vram_max)
                        return 0xff;
                return svga->vram[addr & svga->vram_mask];
        }
        else if (svga->chain2_read)
        {
                readplane = (readplane & 2) | (addr & 1);
                addr &= ~1;
                addr <<= 2;
        }
        else
                addr<<=2;

        addr &= svga->decode_mask;
        
        if (latch_addr >= svga->vram_max)
        {
                svga->la = svga->lb = svga->lc = svga->ld = 0xff;
        }
        else
        {   
                latch_addr &= svga->vram_mask;
                svga->la = svga->vram[latch_addr];
                svga->lb = svga->vram[latch_addr | 0x1];
                svga->lc = svga->vram[latch_addr | 0x2];
                svga->ld = svga->vram[latch_addr | 0x3];
        }

        if (addr >= svga->vram_max)
                return 0xff;
        
        addr &= svga->vram_mask;
        
        if (svga->readmode)
        {
                temp   = svga->la;
                temp  ^= (svga->colourcompare & 1) ? 0xff : 0;
                temp  &= (svga->colournocare & 1)  ? 0xff : 0;
                temp2  = svga->lb;
                temp2 ^= (svga->colourcompare & 2) ? 0xff : 0;
                temp2 &= (svga->colournocare & 2)  ? 0xff : 0;
                temp3  = svga->lc;
                temp3 ^= (svga->colourcompare & 4) ? 0xff : 0;
                temp3 &= (svga->colournocare & 4)  ? 0xff : 0;
                temp4  = svga->ld;
                temp4 ^= (svga->colourcompare & 8) ? 0xff : 0;
                temp4 &= (svga->colournocare & 8)  ? 0xff : 0;
                return ~(temp | temp2 | temp3 | temp4);
        }
//pclog("Read %02X %04X %04X\n",vram[addr|svga->readplane],addr,svga->readplane);

        return svga->vram[addr | readplane];
}

void svga_write_linear(uint32_t addr, uint8_t val, void *p)
{
        svga_t *svga = (svga_t *)p;
        uint8_t vala, valb, valc, vald, wm = svga->writemask;
        int writemask2 = svga->writemask;

        cycles -= video_timing_write_b;
        cycles_lost += video_timing_write_b;

        egawrites++;
        
        if (svga_output) pclog("Write LFB %08X %02X ", addr, val);
        if (!(svga->gdcreg[6] & 1)) 
                svga->fullchange = 2;
        if (svga->chain4 || svga->fb_only)
        {
                writemask2=1<<(addr&3);
                addr&=~3;
        }
        else if (svga->chain2_write)
        {
                writemask2 &= ~0xa;
                if (addr & 1)
                        writemask2 <<= 1;
                addr &= ~1;
                addr <<= 2;
        }
        else
        {
                addr<<=2;
        }
        addr &= svga->decode_mask;
        if (addr >= svga->vram_max)
                return;
        addr &= svga->vram_mask;
        if (svga_output) pclog("%08X\n", addr);
        svga->changedvram[addr >> 12]=changeframecount;
        
        switch (svga->writemode)
        {
                case 1:
                if (writemask2 & 1) svga->vram[addr]       = svga->la;
                if (writemask2 & 2) svga->vram[addr | 0x1] = svga->lb;
                if (writemask2 & 4) svga->vram[addr | 0x2] = svga->lc;
                if (writemask2 & 8) svga->vram[addr | 0x3] = svga->ld;
                break;
                case 0:
                if (svga->gdcreg[3] & 7) 
                        val = svga_rotate[svga->gdcreg[3] & 7][val];
                if (svga->gdcreg[8] == 0xff && !(svga->gdcreg[3] & 0x18) && (!svga->gdcreg[1] || svga->set_reset_disabled))
                {
                        if (writemask2 & 1) svga->vram[addr]       = val;
                        if (writemask2 & 2) svga->vram[addr | 0x1] = val;
                        if (writemask2 & 4) svga->vram[addr | 0x2] = val;
                        if (writemask2 & 8) svga->vram[addr | 0x3] = val;
                }
                else
                {
                        if (svga->gdcreg[1] & 1) vala = (svga->gdcreg[0] & 1) ? 0xff : 0;
                        else                     vala = val;
                        if (svga->gdcreg[1] & 2) valb = (svga->gdcreg[0] & 2) ? 0xff : 0;
                        else                     valb = val;
                        if (svga->gdcreg[1] & 4) valc = (svga->gdcreg[0] & 4) ? 0xff : 0;
                        else                     valc = val;
                        if (svga->gdcreg[1] & 8) vald = (svga->gdcreg[0] & 8) ? 0xff : 0;
                        else                     vald = val;

                        switch (svga->gdcreg[3] & 0x18)
                        {
                                case 0: /*Set*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | (svga->la & ~svga->gdcreg[8]);
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | (svga->lb & ~svga->gdcreg[8]);
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | (svga->lc & ~svga->gdcreg[8]);
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | (svga->ld & ~svga->gdcreg[8]);
                                break;
                                case 8: /*AND*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala | ~svga->gdcreg[8]) & svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb | ~svga->gdcreg[8]) & svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc | ~svga->gdcreg[8]) & svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald | ~svga->gdcreg[8]) & svga->ld;
                                break;
                                case 0x10: /*OR*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | svga->ld;
                                break;
                                case 0x18: /*XOR*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) ^ svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) ^ svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) ^ svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) ^ svga->ld;
                                break;
                        }
//                        pclog("- %02X %02X %02X %02X   %08X\n",vram[addr],vram[addr|0x1],vram[addr|0x2],vram[addr|0x3],addr);
                }
                break;
                case 2:
                if (!(svga->gdcreg[3] & 0x18) && (!svga->gdcreg[1] || svga->set_reset_disabled))
                {
                        if (writemask2 & 1) svga->vram[addr]       = (((val & 1) ? 0xff : 0) & svga->gdcreg[8]) | (svga->la & ~svga->gdcreg[8]);
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (((val & 2) ? 0xff : 0) & svga->gdcreg[8]) | (svga->lb & ~svga->gdcreg[8]);
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (((val & 4) ? 0xff : 0) & svga->gdcreg[8]) | (svga->lc & ~svga->gdcreg[8]);
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (((val & 8) ? 0xff : 0) & svga->gdcreg[8]) | (svga->ld & ~svga->gdcreg[8]);
                }
                else
                {
                        vala = ((val & 1) ? 0xff : 0);
                        valb = ((val & 2) ? 0xff : 0);
                        valc = ((val & 4) ? 0xff : 0);
                        vald = ((val & 8) ? 0xff : 0);
                        switch (svga->gdcreg[3] & 0x18)
                        {
                                case 0: /*Set*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | (svga->la & ~svga->gdcreg[8]);
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | (svga->lb & ~svga->gdcreg[8]);
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | (svga->lc & ~svga->gdcreg[8]);
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | (svga->ld & ~svga->gdcreg[8]);
                                break;
                                case 8: /*AND*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala | ~svga->gdcreg[8]) & svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb | ~svga->gdcreg[8]) & svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc | ~svga->gdcreg[8]) & svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald | ~svga->gdcreg[8]) & svga->ld;
                                break;
                                case 0x10: /*OR*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | svga->ld;
                                break;
                                case 0x18: /*XOR*/
                                if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) ^ svga->la;
                                if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) ^ svga->lb;
                                if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) ^ svga->lc;
                                if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) ^ svga->ld;
                                break;
                        }
                }
                break;
                case 3:
                if (svga->gdcreg[3] & 7) 
                        val = svga_rotate[svga->gdcreg[3] & 7][val];
                wm = svga->gdcreg[8];
                svga->gdcreg[8] &= val;

                vala = (svga->gdcreg[0] & 1) ? 0xff : 0;
                valb = (svga->gdcreg[0] & 2) ? 0xff : 0;
                valc = (svga->gdcreg[0] & 4) ? 0xff : 0;
                vald = (svga->gdcreg[0] & 8) ? 0xff : 0;
                switch (svga->gdcreg[3] & 0x18)
                {
                        case 0: /*Set*/
                        if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | (svga->la & ~svga->gdcreg[8]);
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | (svga->lb & ~svga->gdcreg[8]);
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | (svga->lc & ~svga->gdcreg[8]);
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | (svga->ld & ~svga->gdcreg[8]);
                        break;
                        case 8: /*AND*/
                        if (writemask2 & 1) svga->vram[addr]       = (vala | ~svga->gdcreg[8]) & svga->la;
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (valb | ~svga->gdcreg[8]) & svga->lb;
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (valc | ~svga->gdcreg[8]) & svga->lc;
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (vald | ~svga->gdcreg[8]) & svga->ld;
                        break;
                        case 0x10: /*OR*/
                        if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) | svga->la;
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) | svga->lb;
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) | svga->lc;
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) | svga->ld;
                        break;
                        case 0x18: /*XOR*/
                        if (writemask2 & 1) svga->vram[addr]       = (vala & svga->gdcreg[8]) ^ svga->la;
                        if (writemask2 & 2) svga->vram[addr | 0x1] = (valb & svga->gdcreg[8]) ^ svga->lb;
                        if (writemask2 & 4) svga->vram[addr | 0x2] = (valc & svga->gdcreg[8]) ^ svga->lc;
                        if (writemask2 & 8) svga->vram[addr | 0x3] = (vald & svga->gdcreg[8]) ^ svga->ld;
                        break;
                }
                svga->gdcreg[8] = wm;
                break;
        }
}

uint8_t svga_read_linear(uint32_t addr, void *p)
{
        svga_t *svga = (svga_t *)p;
        uint8_t temp, temp2, temp3, temp4;
        int readplane = svga->readplane;
  
        cycles -= video_timing_read_b;
        cycles_lost += video_timing_read_b;

        egareads++;
        
        if (svga->chain4 || svga->fb_only) 
        { 
                addr &= svga->decode_mask;
                if (addr >= svga->vram_max)
                        return 0xff;
                return svga->vram[addr & svga->vram_mask]; 
        }
        else if (svga->chain2_read)
        {
                readplane = (readplane & 2) | (addr & 1);
                addr &= ~1;
                addr <<= 2;
        }
        else
                addr<<=2;

        addr &= svga->decode_mask;
        
        if (addr >= svga->vram_max)
                return 0xff;
                
        addr &= svga->vram_mask;

        svga->la = svga->vram[addr];
        svga->lb = svga->vram[addr | 0x1];
        svga->lc = svga->vram[addr | 0x2];
        svga->ld = svga->vram[addr | 0x3];
        if (svga->readmode)
        {
                temp   = svga->la;
                temp  ^= (svga->colourcompare & 1) ? 0xff : 0;
                temp  &= (svga->colournocare & 1)  ? 0xff : 0;
                temp2  = svga->lb;
                temp2 ^= (svga->colourcompare & 2) ? 0xff : 0;
                temp2 &= (svga->colournocare & 2)  ? 0xff : 0;
                temp3  = svga->lc;
                temp3 ^= (svga->colourcompare & 4) ? 0xff : 0;
                temp3 &= (svga->colournocare & 4)  ? 0xff : 0;
                temp4  = svga->ld;
                temp4 ^= (svga->colourcompare & 8) ? 0xff : 0;
                temp4 &= (svga->colournocare & 8)  ? 0xff : 0;
                return ~(temp | temp2 | temp3 | temp4);
        }
        return svga->vram[addr | readplane];
}

void svga_doblit(int y1, int y2, int wx, int wy, svga_t *svga)
{
	int y_add = (enable_overscan) ? overscan_y : 0;
	int x_add = (enable_overscan) ? 16 : 0;
	uint32_t *p, i, j;

        svga->frames++;

	if ((xsize > 2032) || (ysize > 2032)) {
		x_add = 0;
		y_add = 0;
		suppress_overscan = 1;
	} else
		suppress_overscan = 0;

        if (y1 > y2) {
                video_blit_memtoscreen(32, 0, 0, 0, xsize + x_add, ysize + y_add);
                return;
        }

	if ((wx != xsize) || ((wy + 1) != ysize) || video_force_resize_get()) {
		/* Screen res has changed.. fix up, and let them know. */
                xsize = wx;
                ysize = wy+1;
                if (xsize<64) xsize = 640;
                if (ysize<32) ysize = 200;

                set_screen_size(xsize+x_add,ysize+y_add);

		if (video_force_resize_get())
			video_force_resize_set(0);
        }

	if (enable_overscan && !suppress_overscan) {
		if ((wx >= 160) && ((wy + 1) >= 120)) {
			/* Draw (overscan_size - scroll size) lines of overscan on top. */
			for (i  = 0; i < (y_add >> 1); i++) {
				p = &((uint32_t *)buffer32->line[i & 0x7ff])[32];

				for (j = 0; j < (xsize + x_add); j++)
					p[j] = svga_color_transform(svga->pallook[svga->attrregs[0x11]]);
			}

			/* Draw (overscan_size + scroll size) lines of overscan on the bottom. */
			for (i  = 0; i < (y_add >> 1); i++) {
				p = &((uint32_t *)buffer32->line[(ysize + (y_add >> 1) + i) & 0x7ff])[32];

				for (j = 0; j < (xsize + x_add); j++)
					p[j] = svga_color_transform(svga->pallook[svga->attrregs[0x11]]);
			}

			for (i = (y_add >> 1); i < (ysize + (y_add >> 1)); i ++) {
				p = &((uint32_t *)buffer32->line[i & 0x7ff])[32];

				for (j = 0; j < 8; j++) {
					p[j] = svga_color_transform(svga->pallook[svga->attrregs[0x11]]);
					p[xsize + (x_add >> 1) + j] = svga_color_transform(svga->pallook[svga->attrregs[0x11]]);
				}
			}
		}
	}

        video_blit_memtoscreen(32, 0, y1, y2 + y_add, xsize + x_add, ysize + y_add);
}

void svga_writew(uint32_t addr, uint16_t val, void *p)
{
        svga_t *svga = (svga_t *)p;
        if (!svga->fast)
        {
                svga_write(addr, val, p);
                svga_write(addr + 1, val >> 8, p);
                return;
        }
        
        egawrites += 2;

        cycles -= video_timing_write_w;
        cycles_lost += video_timing_write_w;

        if (svga_output) pclog("svga_writew: %05X ", addr);
        addr = (addr & svga->banked_mask) + svga->write_bank;
        addr &= svga->decode_mask;
        if (addr >= svga->vram_max)
                return;
        addr &= svga->vram_mask;
        if (svga_output) pclog("%08X (%i, %i) %04X\n", addr, addr & 1023, addr >> 10, val);
        svga->changedvram[addr >> 12] = changeframecount;
        *(uint16_t *)&svga->vram[addr] = val;
}

void svga_writel(uint32_t addr, uint32_t val, void *p)
{
        svga_t *svga = (svga_t *)p;
        
        if (!svga->fast)
        {
                svga_write(addr, val, p);
                svga_write(addr + 1, val >> 8, p);
                svga_write(addr + 2, val >> 16, p);
                svga_write(addr + 3, val >> 24, p);
                return;
        }
        
        egawrites += 4;

        cycles -= video_timing_write_l;
        cycles_lost += video_timing_write_l;

        if (svga_output) pclog("svga_writel: %05X ", addr);
        addr = (addr & svga->banked_mask) + svga->write_bank;
        addr &= svga->decode_mask;
        if (addr >= svga->vram_max)
                return;
        addr &= svga->vram_mask;
        if (svga_output) pclog("%08X (%i, %i) %08X\n", addr, addr & 1023, addr >> 10, val);
        
        svga->changedvram[addr >> 12] = changeframecount;
        *(uint32_t *)&svga->vram[addr] = val;
}

uint16_t svga_readw(uint32_t addr, void *p)
{
        svga_t *svga = (svga_t *)p;
        
        if (!svga->fast)
           return svga_read(addr, p) | (svga_read(addr + 1, p) << 8);
        
        egareads += 2;

        cycles -= video_timing_read_w;
        cycles_lost += video_timing_read_w;

//        pclog("Readw %05X ", addr);
        addr = (addr & svga->banked_mask) + svga->read_bank;
        addr &= svga->decode_mask;
//        pclog("%08X %04X\n", addr, *(uint16_t *)&vram[addr]);
        if (addr >= svga->vram_max)
                return 0xffff;
        
        return *(uint16_t *)&svga->vram[addr & svga->vram_mask];
}

uint32_t svga_readl(uint32_t addr, void *p)
{
        svga_t *svga = (svga_t *)p;
        
        if (!svga->fast)
           return svga_read(addr, p) | (svga_read(addr + 1, p) << 8) | (svga_read(addr + 2, p) << 16) | (svga_read(addr + 3, p) << 24);
        
        egareads += 4;

        cycles -= video_timing_read_l;
        cycles_lost += video_timing_read_l;

//        pclog("Readl %05X ", addr);
        addr = (addr & svga->banked_mask) + svga->read_bank;
        addr &= svga->decode_mask;
//        pclog("%08X %08X\n", addr, *(uint32_t *)&vram[addr]);
        if (addr >= svga->vram_max)
                return 0xffffffff;
        
        return *(uint32_t *)&svga->vram[addr & svga->vram_mask];
}

void svga_writew_linear(uint32_t addr, uint16_t val, void *p)
{
        svga_t *svga = (svga_t *)p;
        
        if (!svga->fast)
        {
                svga_write_linear(addr, val, p);
                svga_write_linear(addr + 1, val >> 8, p);
                return;
        }
        
        egawrites += 2;

        cycles -= video_timing_write_w;
        cycles_lost += video_timing_write_w;

	if (svga_output) pclog("Write LFBw %08X %04X\n", addr, val);
        addr &= svga->decode_mask;
        if (addr >= svga->vram_max)
                return;
        addr &= svga->vram_mask;
        svga->changedvram[addr >> 12] = changeframecount;
        *(uint16_t *)&svga->vram[addr] = val;
}

void svga_writel_linear(uint32_t addr, uint32_t val, void *p)
{
        svga_t *svga = (svga_t *)p;
        
        if (!svga->fast)
        {
                svga_write_linear(addr, val, p);
                svga_write_linear(addr + 1, val >> 8, p);
                svga_write_linear(addr + 2, val >> 16, p);
                svga_write_linear(addr + 3, val >> 24, p);
                return;
        }
        
        egawrites += 4;

        cycles -= video_timing_write_l;
        cycles_lost += video_timing_write_l;

	if (svga_output) pclog("Write LFBl %08X %08X\n", addr, val);
        addr &= svga->decode_mask;
        if (addr >= svga->vram_max)
                return;
        addr &= svga->vram_mask;
        svga->changedvram[addr >> 12] = changeframecount;
        *(uint32_t *)&svga->vram[addr] = val;
}

uint16_t svga_readw_linear(uint32_t addr, void *p)
{
        svga_t *svga = (svga_t *)p;
        
        if (!svga->fast)
           return svga_read_linear(addr, p) | (svga_read_linear(addr + 1, p) << 8);
        
        egareads += 2;

        cycles -= video_timing_read_w;
        cycles_lost += video_timing_read_w;

        addr &= svga->decode_mask;
        if (addr >= svga->vram_max)
                return 0xffff;
        
        return *(uint16_t *)&svga->vram[addr & svga->vram_mask];
}

uint32_t svga_readl_linear(uint32_t addr, void *p)
{
        svga_t *svga = (svga_t *)p;
        
        if (!svga->fast)
           return svga_read_linear(addr, p) | (svga_read_linear(addr + 1, p) << 8) | (svga_read_linear(addr + 2, p) << 16) | (svga_read_linear(addr + 3, p) << 24);
        
        egareads += 4;

        cycles -= video_timing_read_l;
        cycles_lost += video_timing_read_l;

        addr &= svga->decode_mask;
        if (addr >= svga->vram_max)
                return 0xffffffff;

        return *(uint32_t *)&svga->vram[addr & svga->vram_mask];
}


void svga_add_status_info(char *s, int max_len, void *p)
{
        svga_t *svga = (svga_t *)p;
        char temps[128];
        
        if (svga->chain4) strcpy(temps, "SVGA chained (possibly mode 13h)\n");
        else              strcpy(temps, "SVGA unchained (possibly mode-X)\n");
        strncat(s, temps, max_len);

        if (!svga->video_bpp) strcpy(temps, "SVGA in text mode\n");
        else                  sprintf(temps, "SVGA colour depth : %i bpp\n", svga->video_bpp);
        strncat(s, temps, max_len);
        
        sprintf(temps, "SVGA resolution : %i x %i\n", svga->video_res_x, svga->video_res_y);
        strncat(s, temps, max_len);
        
        sprintf(temps, "SVGA refresh rate : %i Hz\n\n", svga->frames);
        svga->frames = 0;
        strncat(s, temps, max_len);
}