Files
86Box/src/video/vid_cga.c
2023-01-07 17:02:23 -05:00

680 lines
23 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 the old and new IBM CGA graphics cards.
*
*
*
* 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 <string.h>
#include <stdlib.h>
#include <wchar.h>
#include <math.h>
#include <86box/86box.h>
#include "cpu.h"
#include <86box/io.h>
#include <86box/timer.h>
#include <86box/pit.h>
#include <86box/mem.h>
#include <86box/rom.h>
#include <86box/device.h>
#include <86box/video.h>
#include <86box/vid_cga.h>
#include <86box/vid_cga_comp.h>
#define CGA_RGB 0
#define CGA_COMPOSITE 1
#define COMPOSITE_OLD 0
#define COMPOSITE_NEW 1
static uint8_t crtcmask[32] = {
0xff, 0xff, 0xff, 0xff, 0x7f, 0x1f, 0x7f, 0x7f, 0xf3, 0x1f, 0x7f, 0x1f, 0x3f, 0xff, 0x3f, 0xff,
0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
static video_timings_t timing_cga = { .type = VIDEO_ISA, .write_b = 8, .write_w = 16, .write_l = 32, .read_b = 8, .read_w = 16, .read_l = 32 };
void cga_recalctimings(cga_t *cga);
void
cga_out(uint16_t addr, uint8_t val, void *p)
{
cga_t *cga = (cga_t *) p;
uint8_t old;
if ((addr >= 0x3d0) && (addr <= 0x3d7))
addr = (addr & 0xff9) | 0x004;
switch (addr) {
case 0x3D4:
cga->crtcreg = val & 31;
return;
case 0x3D5:
old = cga->crtc[cga->crtcreg];
cga->crtc[cga->crtcreg] = val & crtcmask[cga->crtcreg];
if (old != val) {
if ((cga->crtcreg < 0xe) || (cga->crtcreg > 0x10)) {
cga->fullchange = changeframecount;
cga_recalctimings(cga);
}
}
return;
case 0x3D8:
old = cga->cgamode;
cga->cgamode = val;
if (old ^ val) {
if ((old ^ val) & 0x05)
update_cga16_color(val);
cga_recalctimings(cga);
}
return;
case 0x3D9:
old = cga->cgacol;
cga->cgacol = val;
if (old ^ val)
cga_recalctimings(cga);
return;
}
}
uint8_t
cga_in(uint16_t addr, void *p)
{
cga_t *cga = (cga_t *) p;
uint8_t ret = 0xff;
if ((addr >= 0x3d0) && (addr <= 0x3d7))
addr = (addr & 0xff9) | 0x004;
switch (addr) {
case 0x3D4:
ret = cga->crtcreg;
break;
case 0x3D5:
ret = cga->crtc[cga->crtcreg];
break;
case 0x3DA:
ret = cga->cgastat;
break;
}
return ret;
}
void
cga_pravetz_out(uint16_t addr, uint8_t val, void *p)
{
cga_t *cga = (cga_t *) p;
cga->fontbase = (((unsigned int) val) << 8);
}
uint8_t
cga_pravetz_in(uint16_t addr, void *p)
{
cga_t *cga = (cga_t *) p;
return (cga->fontbase >> 8);
}
void
cga_waitstates(void *p)
{
int ws_array[16] = { 3, 4, 5, 6, 7, 8, 4, 5, 6, 7, 8, 4, 5, 6, 7, 8 };
int ws;
ws = ws_array[cycles & 0xf];
cycles -= ws;
}
void
cga_write(uint32_t addr, uint8_t val, void *p)
{
cga_t *cga = (cga_t *) p;
cga->vram[addr & 0x3fff] = val;
if (cga->snow_enabled) {
int offset = ((timer_get_remaining_u64(&cga->timer) / CGACONST) * 2) & 0xfc;
cga->charbuffer[offset] = cga->vram[addr & 0x3fff];
cga->charbuffer[offset | 1] = cga->vram[addr & 0x3fff];
}
cga_waitstates(cga);
}
uint8_t
cga_read(uint32_t addr, void *p)
{
cga_t *cga = (cga_t *) p;
cga_waitstates(cga);
if (cga->snow_enabled) {
int offset = ((timer_get_remaining_u64(&cga->timer) / CGACONST) * 2) & 0xfc;
cga->charbuffer[offset] = cga->vram[addr & 0x3fff];
cga->charbuffer[offset | 1] = cga->vram[addr & 0x3fff];
}
return cga->vram[addr & 0x3fff];
}
void
cga_recalctimings(cga_t *cga)
{
double disptime;
double _dispontime, _dispofftime;
if (cga->cgamode & 1) {
disptime = (double) (cga->crtc[0] + 1);
_dispontime = (double) cga->crtc[1];
} else {
disptime = (double) ((cga->crtc[0] + 1) << 1);
_dispontime = (double) (cga->crtc[1] << 1);
}
_dispofftime = disptime - _dispontime;
_dispontime = _dispontime * CGACONST;
_dispofftime = _dispofftime * CGACONST;
cga->dispontime = (uint64_t) (_dispontime);
cga->dispofftime = (uint64_t) (_dispofftime);
}
void
cga_poll(void *p)
{
cga_t *cga = (cga_t *) p;
uint16_t ca = (cga->crtc[15] | (cga->crtc[14] << 8)) & 0x3fff;
int drawcursor;
int x, c, xs_temp, ys_temp;
int oldvc;
uint8_t chr, attr;
uint8_t border;
uint16_t dat;
int cols[4];
int col;
int oldsc;
if (!cga->linepos) {
timer_advance_u64(&cga->timer, cga->dispofftime);
cga->cgastat |= 1;
cga->linepos = 1;
oldsc = cga->sc;
if ((cga->crtc[8] & 3) == 3)
cga->sc = ((cga->sc << 1) + cga->oddeven) & 7;
if (cga->cgadispon) {
if (cga->displine < cga->firstline) {
cga->firstline = cga->displine;
video_wait_for_buffer();
}
cga->lastline = cga->displine;
for (c = 0; c < 8; c++) {
if ((cga->cgamode & 0x12) == 0x12) {
buffer32->line[(cga->displine << 1)][c] = buffer32->line[(cga->displine << 1) + 1][c] = 0;
if (cga->cgamode & 1) {
buffer32->line[(cga->displine << 1)][c + (cga->crtc[1] << 3) + 8] = buffer32->line[(cga->displine << 1) + 1][c + (cga->crtc[1] << 3) + 8] = 0;
} else {
buffer32->line[(cga->displine << 1)][c + (cga->crtc[1] << 4) + 8] = buffer32->line[(cga->displine << 1) + 1][c + (cga->crtc[1] << 4) + 8] = 0;
}
} else {
buffer32->line[(cga->displine << 1)][c] = buffer32->line[(cga->displine << 1) + 1][c] = (cga->cgacol & 15) + 16;
if (cga->cgamode & 1) {
buffer32->line[(cga->displine << 1)][c + (cga->crtc[1] << 3) + 8] = buffer32->line[(cga->displine << 1) + 1][c + (cga->crtc[1] << 3) + 8] = (cga->cgacol & 15) + 16;
} else {
buffer32->line[(cga->displine << 1)][c + (cga->crtc[1] << 4) + 8] = buffer32->line[(cga->displine << 1) + 1][c + (cga->crtc[1] << 4) + 8] = (cga->cgacol & 15) + 16;
}
}
}
if (cga->cgamode & 1) {
for (x = 0; x < cga->crtc[1]; x++) {
if (cga->cgamode & 8) {
chr = cga->charbuffer[x << 1];
attr = cga->charbuffer[(x << 1) + 1];
} else
chr = attr = 0;
drawcursor = ((cga->ma == ca) && cga->con && cga->cursoron);
cols[1] = (attr & 15) + 16;
if (cga->cgamode & 0x20) {
cols[0] = ((attr >> 4) & 7) + 16;
if ((cga->cgablink & 8) && (attr & 0x80) && !cga->drawcursor)
cols[1] = cols[0];
} else
cols[0] = (attr >> 4) + 16;
if (drawcursor) {
for (c = 0; c < 8; c++) {
buffer32->line[(cga->displine << 1)][(x << 3) + c + 8] = buffer32->line[(cga->displine << 1) + 1][(x << 3) + c + 8] = cols[(fontdat[chr + cga->fontbase][cga->sc & 7] & (1 << (c ^ 7))) ? 1 : 0] ^ 15;
}
} else {
for (c = 0; c < 8; c++) {
buffer32->line[(cga->displine << 1)][(x << 3) + c + 8] = buffer32->line[(cga->displine << 1) + 1][(x << 3) + c + 8] = cols[(fontdat[chr + cga->fontbase][cga->sc & 7] & (1 << (c ^ 7))) ? 1 : 0];
}
}
cga->ma++;
}
} else if (!(cga->cgamode & 2)) {
for (x = 0; x < cga->crtc[1]; x++) {
if (cga->cgamode & 8) {
chr = cga->vram[((cga->ma << 1) & 0x3fff)];
attr = cga->vram[(((cga->ma << 1) + 1) & 0x3fff)];
} else
chr = attr = 0;
drawcursor = ((cga->ma == ca) && cga->con && cga->cursoron);
cols[1] = (attr & 15) + 16;
if (cga->cgamode & 0x20) {
cols[0] = ((attr >> 4) & 7) + 16;
if ((cga->cgablink & 8) && (attr & 0x80))
cols[1] = cols[0];
} else
cols[0] = (attr >> 4) + 16;
cga->ma++;
if (drawcursor) {
for (c = 0; c < 8; c++) {
buffer32->line[(cga->displine << 1)][(x << 4) + (c << 1) + 8] = buffer32->line[(cga->displine << 1)][(x << 4) + (c << 1) + 1 + 8] = buffer32->line[(cga->displine << 1) + 1][(x << 4) + (c << 1) + 8] = buffer32->line[(cga->displine << 1) + 1][(x << 4) + (c << 1) + 1 + 8] = cols[(fontdat[chr + cga->fontbase][cga->sc & 7] & (1 << (c ^ 7))) ? 1 : 0] ^ 15;
}
} else {
for (c = 0; c < 8; c++) {
buffer32->line[(cga->displine << 1)][(x << 4) + (c << 1) + 8] = buffer32->line[(cga->displine << 1)][(x << 4) + (c << 1) + 1 + 8] = buffer32->line[(cga->displine << 1) + 1][(x << 4) + (c << 1) + 8] = buffer32->line[(cga->displine << 1) + 1][(x << 4) + (c << 1) + 1 + 8] = cols[(fontdat[chr + cga->fontbase][cga->sc & 7] & (1 << (c ^ 7))) ? 1 : 0];
}
}
}
} else if (!(cga->cgamode & 16)) {
cols[0] = (cga->cgacol & 15) | 16;
col = (cga->cgacol & 16) ? 24 : 16;
if (cga->cgamode & 4) {
cols[1] = col | 3; /* Cyan */
cols[2] = col | 4; /* Red */
cols[3] = col | 7; /* White */
} else if (cga->cgacol & 32) {
cols[1] = col | 3; /* Cyan */
cols[2] = col | 5; /* Magenta */
cols[3] = col | 7; /* White */
} else {
cols[1] = col | 2; /* Green */
cols[2] = col | 4; /* Red */
cols[3] = col | 6; /* Yellow */
}
for (x = 0; x < cga->crtc[1]; x++) {
if (cga->cgamode & 8)
dat = (cga->vram[((cga->ma << 1) & 0x1fff) + ((cga->sc & 1) * 0x2000)] << 8) | cga->vram[((cga->ma << 1) & 0x1fff) + ((cga->sc & 1) * 0x2000) + 1];
else
dat = 0;
cga->ma++;
for (c = 0; c < 8; c++) {
buffer32->line[(cga->displine << 1)][(x << 4) + (c << 1) + 8] = buffer32->line[(cga->displine << 1)][(x << 4) + (c << 1) + 1 + 8] = buffer32->line[(cga->displine << 1) + 1][(x << 4) + (c << 1) + 8] = buffer32->line[(cga->displine << 1) + 1][(x << 4) + (c << 1) + 1 + 8] = cols[dat >> 14];
dat <<= 2;
}
}
} else {
cols[0] = 0;
cols[1] = (cga->cgacol & 15) + 16;
for (x = 0; x < cga->crtc[1]; x++) {
if (cga->cgamode & 8)
dat = (cga->vram[((cga->ma << 1) & 0x1fff) + ((cga->sc & 1) * 0x2000)] << 8) | cga->vram[((cga->ma << 1) & 0x1fff) + ((cga->sc & 1) * 0x2000) + 1];
else
dat = 0;
cga->ma++;
for (c = 0; c < 16; c++) {
buffer32->line[(cga->displine << 1)][(x << 4) + c + 8] = buffer32->line[(cga->displine << 1) + 1][(x << 4) + c + 8] = cols[dat >> 15];
dat <<= 1;
}
}
}
} else {
cols[0] = ((cga->cgamode & 0x12) == 0x12) ? 0 : (cga->cgacol & 15) + 16;
if (cga->cgamode & 1) {
hline(buffer32, 0, (cga->displine << 1), ((cga->crtc[1] << 3) + 16) << 2, cols[0]);
hline(buffer32, 0, (cga->displine << 1) + 1, ((cga->crtc[1] << 3) + 16) << 2, cols[0]);
} else {
hline(buffer32, 0, (cga->displine << 1), ((cga->crtc[1] << 4) + 16) << 2, cols[0]);
hline(buffer32, 0, (cga->displine << 1) + 1, ((cga->crtc[1] << 4) + 16) << 2, cols[0]);
}
}
if (cga->cgamode & 1)
x = (cga->crtc[1] << 3) + 16;
else
x = (cga->crtc[1] << 4) + 16;
if (cga->composite) {
if (cga->cgamode & 0x10)
border = 0x00;
else
border = cga->cgacol & 0x0f;
Composite_Process(cga->cgamode, border, x >> 2, buffer32->line[(cga->displine << 1)]);
Composite_Process(cga->cgamode, border, x >> 2, buffer32->line[(cga->displine << 1) + 1]);
} else {
video_process_8(x, cga->displine << 1);
video_process_8(x, (cga->displine << 1) + 1);
}
cga->sc = oldsc;
if (cga->vc == cga->crtc[7] && !cga->sc)
cga->cgastat |= 8;
cga->displine++;
if (cga->displine >= 360)
cga->displine = 0;
} else {
timer_advance_u64(&cga->timer, cga->dispontime);
cga->linepos = 0;
if (cga->vsynctime) {
cga->vsynctime--;
if (!cga->vsynctime)
cga->cgastat &= ~8;
}
if (cga->sc == (cga->crtc[11] & 31) || ((cga->crtc[8] & 3) == 3 && cga->sc == ((cga->crtc[11] & 31) >> 1))) {
cga->con = 0;
cga->coff = 1;
}
if ((cga->crtc[8] & 3) == 3 && cga->sc == (cga->crtc[9] >> 1))
cga->maback = cga->ma;
if (cga->vadj) {
cga->sc++;
cga->sc &= 31;
cga->ma = cga->maback;
cga->vadj--;
if (!cga->vadj) {
cga->cgadispon = 1;
cga->ma = cga->maback = (cga->crtc[13] | (cga->crtc[12] << 8)) & 0x3fff;
cga->sc = 0;
}
} else if (cga->sc == cga->crtc[9]) {
cga->maback = cga->ma;
cga->sc = 0;
oldvc = cga->vc;
cga->vc++;
cga->vc &= 127;
if (cga->vc == cga->crtc[6])
cga->cgadispon = 0;
if (oldvc == cga->crtc[4]) {
cga->vc = 0;
cga->vadj = cga->crtc[5];
if (!cga->vadj) {
cga->cgadispon = 1;
cga->ma = cga->maback = (cga->crtc[13] | (cga->crtc[12] << 8)) & 0x3fff;
}
switch (cga->crtc[10] & 0x60) {
case 0x20:
cga->cursoron = 0;
break;
case 0x60:
cga->cursoron = cga->cgablink & 0x10;
break;
default:
cga->cursoron = cga->cgablink & 0x08;
break;
}
}
if (cga->vc == cga->crtc[7]) {
cga->cgadispon = 0;
cga->displine = 0;
cga->vsynctime = 16;
if (cga->crtc[7]) {
if (cga->cgamode & 1)
x = (cga->crtc[1] << 3) + 16;
else
x = (cga->crtc[1] << 4) + 16;
cga->lastline++;
xs_temp = x;
ys_temp = (cga->lastline - cga->firstline) << 1;
if ((xs_temp > 0) && (ys_temp > 0)) {
if (xs_temp < 64)
xs_temp = 656;
if (ys_temp < 32)
ys_temp = 400;
if (!enable_overscan)
xs_temp -= 16;
if ((cga->cgamode & 8) && ((xs_temp != xsize) || (ys_temp != ysize) || video_force_resize_get())) {
xsize = xs_temp;
ysize = ys_temp;
set_screen_size(xsize, ysize + (enable_overscan ? 16 : 0));
if (video_force_resize_get())
video_force_resize_set(0);
}
if (enable_overscan) {
video_blit_memtoscreen(0, (cga->firstline - 4) << 1,
xsize, ((cga->lastline - cga->firstline) + 8) << 1);
} else {
video_blit_memtoscreen(8, cga->firstline << 1,
xsize, (cga->lastline - cga->firstline) << 1);
}
}
frames++;
video_res_x = xsize;
video_res_y = ysize;
if (cga->cgamode & 1) {
video_res_x /= 8;
video_res_y /= cga->crtc[9] + 1;
video_bpp = 0;
} else if (!(cga->cgamode & 2)) {
video_res_x /= 16;
video_res_y /= cga->crtc[9] + 1;
video_bpp = 0;
} else if (!(cga->cgamode & 16)) {
video_res_x /= 2;
video_bpp = 2;
} else
video_bpp = 1;
}
cga->firstline = 1000;
cga->lastline = 0;
cga->cgablink++;
cga->oddeven ^= 1;
}
} else {
cga->sc++;
cga->sc &= 31;
cga->ma = cga->maback;
}
if (cga->cgadispon)
cga->cgastat &= ~1;
if ((cga->sc == (cga->crtc[10] & 31) || ((cga->crtc[8] & 3) == 3 && cga->sc == ((cga->crtc[10] & 31) >> 1))))
cga->con = 1;
if (cga->cgadispon && (cga->cgamode & 1)) {
for (x = 0; x < (cga->crtc[1] << 1); x++)
cga->charbuffer[x] = cga->vram[(((cga->ma << 1) + x) & 0x3fff)];
}
}
}
void
cga_init(cga_t *cga)
{
timer_add(&cga->timer, cga_poll, cga, 1);
cga->composite = 0;
}
void *
cga_standalone_init(const device_t *info)
{
int display_type;
cga_t *cga = malloc(sizeof(cga_t));
memset(cga, 0, sizeof(cga_t));
video_inform(VIDEO_FLAG_TYPE_CGA, &timing_cga);
display_type = device_get_config_int("display_type");
cga->composite = (display_type != CGA_RGB);
cga->revision = device_get_config_int("composite_type");
cga->snow_enabled = device_get_config_int("snow_enabled");
cga->vram = malloc(0x4000);
cga_comp_init(cga->revision);
timer_add(&cga->timer, cga_poll, cga, 1);
mem_mapping_add(&cga->mapping, 0xb8000, 0x08000, cga_read, NULL, NULL, cga_write, NULL, NULL, NULL /*cga->vram*/, MEM_MAPPING_EXTERNAL, cga);
io_sethandler(0x03d0, 0x0010, cga_in, NULL, NULL, cga_out, NULL, NULL, cga);
overscan_x = overscan_y = 16;
cga->rgb_type = device_get_config_int("rgb_type");
cga_palette = (cga->rgb_type << 1);
cgapal_rebuild();
return cga;
}
void *
cga_pravetz_init(const device_t *info)
{
cga_t *cga = cga_standalone_init(info);
loadfont("roms/video/cga/PRAVETZ-VDC2.BIN", 10);
io_removehandler(0x03dd, 0x0001, cga_in, NULL, NULL, cga_out, NULL, NULL, cga);
io_sethandler(0x03dd, 0x0001, cga_pravetz_in, NULL, NULL, cga_pravetz_out, NULL, NULL, cga);
cga->fontbase = 0x0300;
return cga;
}
void
cga_close(void *p)
{
cga_t *cga = (cga_t *) p;
free(cga->vram);
free(cga);
}
void
cga_speed_changed(void *p)
{
cga_t *cga = (cga_t *) p;
cga_recalctimings(cga);
}
// clang-format off
const device_config_t cga_config[] = {
{
.name = "display_type",
.description = "Display type",
.type = CONFIG_SELECTION,
.default_int = CGA_RGB,
.selection = {
{
.description = "RGB",
.value = CGA_RGB
},
{
.description = "Composite",
.value = CGA_COMPOSITE
},
{
.description = ""
}
}
},
{
.name = "composite_type",
.description = "Composite type",
.type = CONFIG_SELECTION,
.default_int = COMPOSITE_OLD,
.selection = {
{
.description = "Old",
.value = COMPOSITE_OLD
},
{
.description = "New",
.value = COMPOSITE_NEW
},
{
.description = ""
}
}
},
{
.name = "rgb_type",
.description = "RGB type",
.type = CONFIG_SELECTION,
.default_int = 0,
.selection = {
{
.description = "Color",
.value = 0
},
{
.description = "Green Monochrome",
.value = 1
},
{
.description = "Amber Monochrome",
.value = 2
},
{
.description = "Gray Monochrome",
.value = 3
},
{
.description = "Color (no brown)",
.value = 4
},
{
.description = ""
}
}
},
{
.name = "snow_enabled",
.description = "Snow emulation",
.type = CONFIG_BINARY,
.default_int = 1
},
{
.type = CONFIG_END
}
};
// clang-format on
const device_t cga_device = {
.name = "CGA",
.internal_name = "cga",
.flags = DEVICE_ISA,
.local = 0,
.init = cga_standalone_init,
.close = cga_close,
.reset = NULL,
{ .available = NULL },
.speed_changed = cga_speed_changed,
.force_redraw = NULL,
.config = cga_config
};
const device_t cga_pravetz_device = {
.name = "Pravetz VDC-2",
.internal_name = "cga_pravetz",
.flags = DEVICE_ISA,
.local = 0,
.init = cga_pravetz_init,
.close = cga_close,
.reset = NULL,
{ .available = NULL },
.speed_changed = cga_speed_changed,
.force_redraw = NULL,
.config = cga_config
};