/*
 * 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.
 *
 *		ATI 68860 RAMDAC emulation (for Mach64)
 *
 *		ATI 68860/68880 Truecolor DACs:
 *		  REG08 (R/W):
 *		  bit 0-?  Always 2 ??
 *
 *		  REG0A (R/W):
 *		  bit 0-?  Always 1Dh ??
 *
 *		  REG0B (R/W):  (GMR ?)
 *		  bit 0-7  Mode. 82h: 4bpp, 83h: 8bpp,
 *				 A0h: 15bpp, A1h: 16bpp, C0h: 24bpp,
 *				 E3h: 32bpp  (80h for VGA modes ?)
 *		  
 *		  REG0C (R/W):  Device Setup Register A
 *		  bit   0  Controls 6/8bit DAC. 0: 8bit DAC/LUT, 1: 6bit DAC/LUT
 *		  2-3  Depends on Video memory (= VRAM width ?) .
 *			1: Less than 1Mb, 2: 1Mb, 3: > 1Mb
 *		  5-6  Always set ?
 *		    7  If set can remove "snow" in some cases
 *			(A860_Delay_L ?) ??
 *
 * Version:	@(#)vid_ati68860.c	1.0.5	2018/10/04
 *
 * Authors:	Sarah Walker, <http://pcem-emulator.co.uk/>
 *		Miran Grca, <mgrca8@gmail.com>
 *
 *		Copyright 2008-2018 Sarah Walker.
 *		Copyright 2016-2018 Miran Grca.
 */
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include "../86box.h"
#include "../device.h"
#include "../mem.h"
#include "../timer.h"
#include "video.h"
#include "vid_svga.h"
#include "vid_ati68860_ramdac.h"
#include "vid_svga_render.h"


void
ati68860_ramdac_out(uint16_t addr, uint8_t val, ati68860_ramdac_t *ramdac, svga_t *svga)
{
    switch (addr) {
	case 0: 
		svga_out(0x3c8, val, svga);
		break;
	case 1: 
		svga_out(0x3c9, val, svga); 
		break;
	case 2: 
		svga_out(0x3c6, val, svga); 
		break;
	case 3: 
		svga_out(0x3c7, val, svga); 
		break;
	default:
		ramdac->regs[addr & 0xf] = val;
		switch (addr & 0xf) {
			case 0x4:
				ramdac->dac_addr = val;
				ramdac->dac_pos = 0;
				break;
			case 0x5:
				switch (ramdac->dac_pos) {
					case 0:
						ramdac->dac_r = val;
						ramdac->dac_pos++; 
						break;
					case 1:
						ramdac->dac_g = val;
						ramdac->dac_pos++; 
						break;
					case 2:
						if (ramdac->dac_addr > 1)
							break;
						ramdac->pal[ramdac->dac_addr].r = ramdac->dac_r; 
						ramdac->pal[ramdac->dac_addr].g = ramdac->dac_g;
						ramdac->pal[ramdac->dac_addr].b = val; 
						if (ramdac->ramdac_type == RAMDAC_8BIT)
							ramdac->pallook[ramdac->dac_addr] = makecol32(ramdac->pal[ramdac->dac_addr].r,
												      ramdac->pal[ramdac->dac_addr].g,
												      ramdac->pal[ramdac->dac_addr].b);
						else
							ramdac->pallook[ramdac->dac_addr] = makecol32(video_6to8[ramdac->pal[ramdac->dac_addr].r & 0x3f],
												      video_6to8[ramdac->pal[ramdac->dac_addr].g & 0x3f],
												      video_6to8[ramdac->pal[ramdac->dac_addr].b & 0x3f]);
						ramdac->dac_pos = 0;
						ramdac->dac_addr = (ramdac->dac_addr + 1) & 255; 
						break;
				}
				break;
			case 0xb:
				switch (val) {
					case 0x82:
						ramdac->render = svga_render_4bpp_highres;
						break;
					case 0x83:
						ramdac->render = svga_render_8bpp_highres;
						break;
					case 0xa0: case 0xb0:
						ramdac->render = svga_render_15bpp_highres;
						break;
					case 0xa1: case 0xb1:
						ramdac->render = svga_render_16bpp_highres;
						break;
					case 0xc0: case 0xd0:
						ramdac->render = svga_render_24bpp_highres;
						break;
					case 0xe2: case 0xf7:
						ramdac->render = svga_render_32bpp_highres;
						break;
					case 0xe3:
						ramdac->render = svga_render_ABGR8888_highres;
						break;
					case 0xf2:
						ramdac->render = svga_render_RGBA8888_highres;
						break;
					default:
						ramdac->render = svga_render_8bpp_highres;
						break;
                        	}
				break;
			case 0xc:
				svga_set_ramdac_type(svga, (val & 1) ? RAMDAC_6BIT : RAMDAC_8BIT);
				break;
		}
		break;
    }
}

uint8_t
ati68860_ramdac_in(uint16_t addr, ati68860_ramdac_t *ramdac, svga_t *svga)
{
    uint8_t temp = 0;

    switch (addr) {
	case 0:
		temp = svga_in(0x3c8, svga);
		break;
	case 1:
		temp = svga_in(0x3c9, svga);
		break;
	case 2:
		temp = svga_in(0x3c6, svga);
		break;
	case 3:
		temp = svga_in(0x3c7, svga);
		break;
	case 4: case 8:
		temp = 2; 
		break;
	case 6: case 0xa:
		temp = 0x1d;
		break;
	case 0xf:
		temp = 0xd0;
		break;

	default:
		temp = ramdac->regs[addr & 0xf];
		break;
    }

    return temp;
}


void
ati68860_set_ramdac_type(ati68860_ramdac_t *ramdac, int type)
{
    int c;

    if (ramdac->ramdac_type != type) {
	ramdac->ramdac_type = type;

	for (c = 0; c < 2; c++) {
		if (ramdac->ramdac_type == RAMDAC_8BIT)
			ramdac->pallook[c] = makecol32(ramdac->pal[c].r, ramdac->pal[c].g,
						       ramdac->pal[c].b);
		else
			ramdac->pallook[c] = makecol32(video_6to8[ramdac->pal[c].r & 0x3f], video_6to8[ramdac->pal[c].g & 0x3f],
						       video_6to8[ramdac->pal[c].b & 0x3f]); 
	}
    }
}


static void *
ati68860_ramdac_init(const device_t *info)
{
    ati68860_ramdac_t *ramdac = (ati68860_ramdac_t *) malloc(sizeof(ati68860_ramdac_t));
    memset(ramdac, 0, sizeof(ati68860_ramdac_t));

    ramdac->render = svga_render_8bpp_highres;

    return ramdac;
}


static void
ati68860_ramdac_close(void *priv)
{
    ati68860_ramdac_t *ramdac = (ati68860_ramdac_t *) priv;

    if (ramdac)
	free(ramdac);
}


const device_t ati68860_ramdac_device =
{
        "ATI-68860 RAMDAC",
        0, 0,
        ati68860_ramdac_init, ati68860_ramdac_close,
	NULL, NULL, NULL, NULL
};