Files
86Box/src/video/vid_sc1502x_ramdac.c
Jasmine Iwanek 3b73ce330c src/video
2022-03-18 18:07:09 -04:00

169 lines
3.1 KiB
C

/*
* 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.
*
* Emulation of a Sierra SC1502X RAMDAC.
*
* Used by the TLIVESA1 driver for ET4000.
*
*
*
* 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/86box.h>
#include <86box/device.h>
#include <86box/mem.h>
#include <86box/timer.h>
#include <86box/video.h>
#include <86box/vid_svga.h>
typedef struct
{
int state;
uint8_t ctrl;
} sc1502x_ramdac_t;
void
sc1502x_ramdac_out(uint16_t addr, uint8_t val, void *p, svga_t *svga)
{
sc1502x_ramdac_t *ramdac = (sc1502x_ramdac_t *) p;
int oldbpp = 0;
switch (addr) {
case 0x3C6:
if (ramdac->state == 4) {
ramdac->state = 0;
if (val == 0xFF)
break;
ramdac->ctrl = val;
oldbpp = svga->bpp;
switch ((val & 1) | ((val & 0xc0) >> 5)) {
case 0:
svga->bpp = 8;
break;
case 2:
case 3:
switch (val & 0x20) {
case 0x00:
svga->bpp = 32;
break;
case 0x20:
svga->bpp = 24;
break;
}
break;
case 4:
case 5:
svga->bpp = 15;
break;
case 6:
svga->bpp = 16;
break;
case 7:
if (val & 4) {
switch (val & 0x20) {
case 0x00:
svga->bpp = 32;
break;
case 0x20:
svga->bpp = 24;
break;
}
break;
} else {
svga->bpp = 16;
break;
}
break;
}
if (oldbpp != svga->bpp)
svga_recalctimings(svga);
return;
}
ramdac->state = 0;
break;
case 0x3C7:
case 0x3C8:
case 0x3C9:
ramdac->state = 0;
break;
}
svga_out(addr, val, svga);
}
uint8_t
sc1502x_ramdac_in(uint16_t addr, void *p, svga_t *svga)
{
sc1502x_ramdac_t *ramdac = (sc1502x_ramdac_t *) p;
uint8_t temp = svga_in(addr, svga);
switch (addr) {
case 0x3C6:
if (ramdac->state == 4) {
ramdac->state = 0;
temp = ramdac->ctrl;
break;
}
ramdac->state++;
break;
case 0x3C7:
case 0x3C8:
case 0x3C9:
ramdac->state = 0;
break;
}
return temp;
}
static void *
sc1502x_ramdac_init(const device_t *info)
{
sc1502x_ramdac_t *ramdac = (sc1502x_ramdac_t *) malloc(sizeof(sc1502x_ramdac_t));
memset(ramdac, 0, sizeof(sc1502x_ramdac_t));
return ramdac;
}
static void
sc1502x_ramdac_close(void *priv)
{
sc1502x_ramdac_t *ramdac = (sc1502x_ramdac_t *) priv;
if (ramdac)
free(ramdac);
}
const device_t sc1502x_ramdac_device = {
.name = "Sierra SC1502x RAMDAC",
.internal_name = "sc1502x_ramdac",
.flags = 0,
.local = 0,
.init = sc1502x_ramdac_init,
.close = sc1502x_ramdac_close,
.reset = NULL,
{ .available = NULL },
.speed_changed = NULL,
.force_redraw = NULL,
.config = NULL
};