ref: d8a1f1a647d396bda237df5e996b4d49a948eda9
dir: /sys/src/games/md/md.c/
#include <u.h>
#include <libc.h>
#include <thread.h>
#include <draw.h>
#include <keyboard.h>
#include <mouse.h>
#include "dat.h"
#include "fns.h"
int debug;
u16int *prg;
int nprg;
u8int *sram;
u32int sramctl, nsram, sram0, sram1;
int savefd = -1;
int keys;
int dmaclock, vdpclock, z80clock, audioclock, ymclock, saveclock;
int scale, paused;
QLock pauselock;
Mousectl *mc;
Channel *flushc;
Rectangle picr;
Image *tmp, *bg;
void
flushram(void)
{
if(savefd >= 0)
pwrite(savefd, sram, nsram, 0);
saveclock = 0;
}
static void
loadbat(char *file)
{
static char buf[512];
strncpy(buf, file, sizeof buf - 5);
strcat(buf, ".sav");
savefd = create(buf, ORDWR | OEXCL, 0666);
if(savefd < 0)
savefd = open(buf, ORDWR);
if(savefd < 0)
print("open: %r\n");
else
readn(savefd, sram, nsram);
}
static void
loadrom(char *file)
{
static uchar hdr[512], buf[4096];
u32int v;
u16int *p;
int fd, rc, i;
fd = open(file, OREAD);
if(fd < 0)
sysfatal("open: %r");
if(readn(fd, hdr, 512) < 512)
sysfatal("read: %r");
if(memcmp(hdr + 0x100, "SEGA MEGA DRIVE ", 16) != 0 && memcmp(hdr + 0x100, "SEGA GENESIS ", 16) != 0)
sysfatal("invalid rom");
v = hdr[0x1a0] << 24 | hdr[0x1a1] << 16 | hdr[0x1a2] << 8 | hdr[0x1a3];
if(v != 0)
sysfatal("rom starts at nonzero address");
v = hdr[0x1a4] << 24 | hdr[0x1a5] << 16 | hdr[0x1a6] << 8 | hdr[0x1a7];
nprg = v = v+2 & ~1;
if(nprg == 0)
sysfatal("invalid rom");
p = prg = malloc(v);
if(prg == nil)
sysfatal("malloc: %r");
seek(fd, 0, 0);
while(v != 0){
rc = readn(fd, buf, sizeof buf);
if(rc == 0)
break;
if(rc < 0)
sysfatal("read: %r");
if(rc > v)
rc = v;
for(i = 0; i < rc; i += 2)
*p++ = buf[i] << 8 | buf[i+1];
v -= rc;
}
close(fd);
if(hdr[0x1b0] == 0x52 && hdr[0x1b1] == 0x41){
sramctl = SRAM | hdr[0x1b2] >> 1 & ADDRMASK;
if((hdr[0x1b2] & 0x40) != 0)
sramctl |= BATTERY;
sram0 = hdr[0x1b4] << 24 | hdr[0x1b5] << 16 | hdr[0x1b6] << 8 | hdr[0x1b7] & 0xfe;
sram1 = hdr[0x1b8] << 24 | hdr[0x1b9] << 16 | hdr[0x1ba] << 8 | hdr[0x1bb] | 1;
if(sram1 <= sram0){
print("SRAM of size <= 0?\n");
sramctl = 0;
}else{
nsram = sram1 - sram0;
if((sramctl & ADDRMASK) != ADDRBOTH)
nsram >>= 1;
sram = malloc(nsram);
if(sram == nil)
sysfatal("malloc: %r");
if((sramctl & BATTERY) != 0){
loadbat(file);
atexit(flushram);
}
}
}
}
void
screeninit(void)
{
Point p;
originwindow(screen, Pt(0, 0), screen->r.min);
p = divpt(addpt(screen->r.min, screen->r.max), 2);
picr = (Rectangle){subpt(p, Pt(scale * 160, scale * 112)), addpt(p, Pt(scale * 160, scale * 112))};
if(tmp != nil) freeimage(tmp);
tmp = allocimage(display, Rect(0, 0, scale * 320, scale > 1 ? 1 : scale * 224), XRGB32, scale > 1, 0);
if(bg != nil) freeimage(bg);
bg = allocimage(display, Rect(0, 0, 1, 1), screen->chan, 1, 0xCCCCCCFF);
draw(screen, screen->r, bg, nil, ZP);
}
void
screenproc(void *)
{
extern u8int pic[320*224*4*4];
extern int intla;
Rectangle r;
uchar *s;
int w, h;
enum { AMOUSE, ARESIZE, AFLUSH, AEND };
Alt a[AEND+1] = {
{ mc->c, nil, CHANRCV },
{ mc->resizec, nil, CHANRCV },
{ flushc, nil, CHANRCV },
{ nil, nil, CHANEND }
};
for(;;){
switch(alt(a)){
case ARESIZE:
if(getwindow(display, Refnone) < 0)
sysfatal("resize failed: %r");
screeninit();
/* wet floor */
case AFLUSH:
if(scale == 1){
loadimage(tmp, tmp->r, pic, 320*224*4);
draw(screen, picr, tmp, nil, ZP);
}else{
s = pic;
r = picr;
w = 320*4*scale;
h = scale;
if(intla && (h & 1) == 0)
h >>= 1;
while(r.min.y < picr.max.y){
loadimage(tmp, tmp->r, s, w);
s += w;
r.max.y = r.min.y+h;
draw(screen, r, tmp, nil, ZP);
r.min.y = r.max.y;
}
}
flushimage(display, 1);
break;
}
}
}
void
keyproc(void *)
{
int fd, k;
static char buf[256];
char *s;
Rune r;
fd = open("/dev/kbd", OREAD);
if(fd < 0)
sysfatal("open: %r");
for(;;){
if(read(fd, buf, sizeof(buf) - 1) <= 0)
sysfatal("read /dev/kbd: %r");
if(buf[0] == 'c'){
if(utfrune(buf, Kdel)){
close(fd);
threadexitsall(nil);
}
if(utfrune(buf, 't'))
trace = !trace;
}
if(buf[0] != 'k' && buf[0] != 'K')
continue;
s = buf + 1;
k = 0xc00;
while(*s != 0){
s += chartorune(&r, s);
if(r >= '0' && r <= '9') debug = r - '0';
switch(r){
case Kdel: close(fd); threadexitsall(nil);
case 'c': k |= 0x0020; break;
case 'x': k |= 0x0010; break;
case 'z': k |= 0x1000; break;
case 10: k |= 0x2000; break;
case Kup: k |= 0x0101; break;
case Kdown: k |= 0x0202; break;
case Kleft: k |= 0x0004; break;
case Kright: k |= 0x0008; break;
case Kesc:
if(paused)
qunlock(&pauselock);
else
qlock(&pauselock);
paused = !paused;
break;
}
}
keys = ~k;
}
}
void
threadmain(int argc, char **argv)
{
int t;
scale = 1;
ARGBEGIN{
case 'a':
initaudio();
break;
case '2':
scale = 2;
break;
case '3':
scale = 3;
break;
default:
;
} ARGEND;
if(argc != 1){
fprint(2, "usage: %s [-23a] rom\n", argv0);
threadexitsall("usage");
}
loadrom(*argv);
if(initdraw(nil, nil, argv0) < 0)
sysfatal("initdraw: %r");
flushc = chancreate(sizeof(ulong), 1);
mc = initmouse(nil, screen);
if(mc == nil)
sysfatal("initmouse: %r");
screeninit();
proccreate(keyproc, nil, 8192);
proccreate(screenproc, nil, 8192);
cpureset();
vdpmode();
ymreset();
for(;;){
if(paused != 0){
qlock(&pauselock);
qunlock(&pauselock);
}
if(dma != 1){
t = step() * CPUDIV;
if(dma != 0)
dmastep();
}else{
t = CPUDIV;
dmastep();
}
z80clock -= t;
vdpclock -= t;
audioclock += t;
ymclock += t;
while(vdpclock < 0){
vdpstep();
vdpclock += 8;
}
while(z80clock < 0)
z80clock += z80step() * Z80DIV;
while(audioclock >= SAMPDIV){
audiosample();
audioclock -= SAMPDIV;
}
while(ymclock >= YMDIV){
ymstep();
ymclock -= YMDIV;
}
if(saveclock > 0){
saveclock -= t;
if(saveclock <= 0){
saveclock = 0;
flushram();
}
}
}
}
void
flush(void)
{
static vlong old, delta;
vlong new, diff;
sendul(flushc, 1); /* flush screen */
if(audioout() < 0){
new = nsec();
diff = 0;
if(old != 0){
diff = BILLION/60 - (new - old) - delta;
if(diff >= MILLION)
sleep(diff/MILLION);
}
old = nsec();
if(diff != 0){
diff = (old - new) - (diff / MILLION) * MILLION;
delta += (diff - delta) / 100;
}
}
}