Files
86Box/src/video/vid_sdac_ramdac.c
2023-08-09 16:44:59 -04:00

363 lines
8.9 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.
*
* 87C716 'SDAC' true colour RAMDAC emulation.
*
*
*
* Authors: Sarah Walker, <https://pcem-emulator.co.uk/>
* Miran Grca, <mgrca8@gmail.com>
*
* Copyright 2008-2019 Sarah Walker.
* Copyright 2016-2019 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>
enum {
ICS_5300 = 0,
ICS_5301,
ICS_5340,
ICS_5341,
ICS_5342
};
#define ICS_S3_MASK 7
#define ICS_S3 8
#define S3_86C708 (ICS_5300 | ICS_S3)
#define S3_86C716 (ICS_5342 | ICS_S3)
typedef struct sdac_ramdac_t {
uint16_t regs[256];
int magic_count;
int windex;
int rindex;
int reg_ff;
int rs2;
uint8_t type;
uint8_t command;
} sdac_ramdac_t;
static void
sdac_control_write(sdac_ramdac_t *ramdac, svga_t *svga, uint8_t val)
{
ramdac->command = val;
switch (ramdac->type & ICS_S3_MASK) {
case ICS_5300:
case ICS_5301:
switch (val >> 5) {
default:
case 0x00:
svga->bpp = 8;
break;
case 0x01:
case 0x04:
case 0x05:
svga->bpp = 15;
break;
case 0x03:
case 0x06:
svga->bpp = 16;
break;
case 0x02:
case 0x07:
svga->bpp = 24;
break;
}
break;
case ICS_5340:
case ICS_5341:
case ICS_5342:
switch (val >> 4) {
default:
case 0x00:
case 0x01: /* This is actually 8bpp with two pixels read at a time. */
svga->bpp = 8;
break;
case 0x02:
case 0x03:
case 0x08:
case 0x0a:
svga->bpp = 15;
break;
case 0x05:
case 0x06:
case 0x0c:
svga->bpp = 16;
break;
case 0x04:
case 0x09:
case 0x0e:
svga->bpp = 24;
break;
case 0x07:
svga->bpp = 32;
break;
}
break;
default:
break;
}
svga_recalctimings(svga);
}
static void
sdac_reg_write(sdac_ramdac_t *ramdac, int reg, uint8_t val)
{
if ((reg >= 2 && reg <= 7) || (reg == 0xa) || (reg == 0xe)) {
if (!ramdac->reg_ff)
ramdac->regs[reg] = (ramdac->regs[reg] & 0xff00) | val;
else
ramdac->regs[reg] = (ramdac->regs[reg] & 0x00ff) | (val << 8);
}
ramdac->reg_ff = !ramdac->reg_ff;
if (!ramdac->reg_ff)
ramdac->windex++;
}
static uint8_t
sdac_reg_read(sdac_ramdac_t *ramdac, int reg)
{
uint8_t temp;
if (!ramdac->reg_ff)
temp = ramdac->regs[reg] & 0xff;
else
temp = ramdac->regs[reg] >> 8;
ramdac->reg_ff = !ramdac->reg_ff;
if (!ramdac->reg_ff)
ramdac->rindex++;
return temp;
}
void
sdac_ramdac_out(uint16_t addr, int rs2, uint8_t val, void *priv, svga_t *svga)
{
sdac_ramdac_t *ramdac = (sdac_ramdac_t *) priv;
uint8_t rs = (addr & 0x03);
rs |= ((!!rs2) << 2);
if (rs != 0x02)
ramdac->magic_count = 0;
switch (rs) {
case 0x02:
switch (ramdac->magic_count) {
case 4:
sdac_control_write(ramdac, svga, val);
ramdac->magic_count = 0;
break;
default:
svga_out(addr, val, svga);
break;
}
break;
case 0x00:
case 0x01:
case 0x03:
svga_out(addr, val, svga);
break;
case 0x04:
ramdac->windex = val;
ramdac->reg_ff = 0;
break;
case 0x05:
sdac_reg_write(ramdac, ramdac->windex & 0xff, val);
break;
case 0x06:
sdac_control_write(ramdac, svga, val);
break;
case 0x07:
ramdac->rindex = val;
ramdac->reg_ff = 0;
break;
default:
break;
}
}
uint8_t
sdac_ramdac_in(uint16_t addr, int rs2, void *priv, svga_t *svga)
{
sdac_ramdac_t *ramdac = (sdac_ramdac_t *) priv;
uint8_t temp = 0xff;
uint8_t rs = (addr & 0x03);
rs |= ((!!rs2) << 2);
if (rs != 0x02)
ramdac->magic_count = 0;
switch (rs) {
case 0x02:
switch (ramdac->magic_count) {
case 1:
case 2:
temp = 0x00;
ramdac->magic_count++;
break;
case 3:
temp = (ramdac->type & ICS_S3) ? 0x70 : 0x00;
ramdac->magic_count++;
break;
case 4:
temp = ramdac->command;
ramdac->magic_count = 0;
break;
default:
temp = svga_in(addr, svga);
ramdac->magic_count++;
break;
}
break;
case 0x00:
case 0x01:
case 0x03:
temp = svga_in(addr, svga);
break;
case 0x04:
temp = ramdac->windex;
break;
case 0x05:
temp = sdac_reg_read(ramdac, ramdac->rindex & 0xff);
break;
case 0x06:
temp = ramdac->command;
break;
case 0x07:
temp = ramdac->rindex;
break;
default:
break;
}
return temp;
}
float
sdac_getclock(int clock, void *priv)
{
const sdac_ramdac_t *ramdac = (sdac_ramdac_t *) priv;
float t;
int m;
int n1;
int n2;
if (ramdac->regs[0xe] & (1 << 5))
clock = ramdac->regs[0xe] & 7;
clock &= 7;
if (clock == 0)
return 25175000.0;
if (clock == 1)
return 28322000.0;
m = (ramdac->regs[clock] & 0x7f) + 2;
n1 = ((ramdac->regs[clock] >> 8) & 0x1f) + 2;
n2 = ((ramdac->regs[clock] >> 13) & 0x07);
n2 = (1 << n2);
t = (14318184.0f * (float) m) / (float) (n1 * n2);
return t;
}
void *
sdac_ramdac_init(const device_t *info)
{
sdac_ramdac_t *ramdac = (sdac_ramdac_t *) malloc(sizeof(sdac_ramdac_t));
memset(ramdac, 0, sizeof(sdac_ramdac_t));
ramdac->type = info->local;
ramdac->regs[0] = 0x6128;
ramdac->regs[1] = 0x623d;
return ramdac;
}
static void
sdac_ramdac_close(void *priv)
{
sdac_ramdac_t *ramdac = (sdac_ramdac_t *) priv;
if (ramdac)
free(ramdac);
}
const device_t gendac_ramdac_device = {
.name = "S3 GENDAC 86c708 RAMDAC",
.internal_name = "gendac_ramdac",
.flags = 0,
.local = S3_86C708,
.init = sdac_ramdac_init,
.close = sdac_ramdac_close,
.reset = NULL,
{ .available = NULL },
.speed_changed = NULL,
.force_redraw = NULL,
.config = NULL
};
const device_t tseng_ics5301_ramdac_device = {
.name = "Tseng ICS5301 GENDAC RAMDAC",
.internal_name = "tseng_ics5301_ramdac",
.flags = 0,
.local = ICS_5301,
.init = sdac_ramdac_init,
.close = sdac_ramdac_close,
.reset = NULL,
{ .available = NULL },
.speed_changed = NULL,
.force_redraw = NULL,
.config = NULL
};
const device_t tseng_ics5341_ramdac_device = {
.name = "Tseng ICS5341 GENDAC RAMDAC",
.internal_name = "tseng_ics5341_ramdac",
.flags = 0,
.local = ICS_5341,
.init = sdac_ramdac_init,
.close = sdac_ramdac_close,
.reset = NULL,
{ .available = NULL },
.speed_changed = NULL,
.force_redraw = NULL,
.config = NULL
};
const device_t sdac_ramdac_device = {
.name = "S3 SDAC 86c716 RAMDAC",
.internal_name = "sdac_ramdac",
.flags = 0,
.local = S3_86C716,
.init = sdac_ramdac_init,
.close = sdac_ramdac_close,
.reset = NULL,
{ .available = NULL },
.speed_changed = NULL,
.force_redraw = NULL,
.config = NULL
};