sys/src/games/gba/ev.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <thread.h>
   4 #include "dat.h"
   5 #include "fns.h"
   6
   7 typedef struct {
   8         u16int *cnt;
   9         Event;
  10         u16int val;
  11         int clock;
  12         u8int i, sh, snd;
  13 } Timer;
  14
  15 typedef struct fifo fifo;
  16 struct fifo {
  17         u32int d[8];
  18         u8int head, level, headpos;
  19 };
  20 fifo sndfifo[2];
  21
  22 Event *elist;
  23 Timer timers[4];
  24 Event evhblank;
  25 extern Event evsamp;
  26 Event *events[NEVENT] = {&timers[0].Event, &timers[1].Event, &timers[2].Event, &timers[3].Event, &evhblank, &evsamp};
  27
  28 Var evvars[] = {
  29         VAR(clock),
  30         ARR(sndfifo[0].d), VAR(sndfifo[0].head), VAR(sndfifo[0].level), VAR(sndfifo[0].headpos),
  31         ARR(sndfifo[1].d), VAR(sndfifo[1].head), VAR(sndfifo[1].level), VAR(sndfifo[1].headpos),
  32         VAR(timers[0].val), VAR(timers[0].clock), VAR(timers[0].sh), VAR(timers[0].snd),
  33         VAR(timers[1].val), VAR(timers[1].clock), VAR(timers[1].sh), VAR(timers[1].snd),
  34         VAR(timers[2].val), VAR(timers[2].clock), VAR(timers[2].sh), VAR(timers[2].snd),
  35         VAR(timers[3].val), VAR(timers[3].clock), VAR(timers[3].sh), VAR(timers[3].snd),
  36         {nil, 0, 0},
  37 };
  38
  39 void
  40 addevent(Event *ev, int time)
  41 {
  42         Event **p, *e;
  43         int t;
  44
  45         t = time;
  46         for(p = &elist; (e = *p) != nil; p = &e->next){
  47                 if(t < e->time){
  48                         e->time -= t;
  49                         break;
  50                 }
  51                 t -= e->time;
  52         }
  53         ev->next = e;
  54         ev->time = t;
  55         *p = ev;
  56 }
  57
  58 void
  59 delevent(Event *ev)
  60 {
  61         Event **p, *e;
  62
  63         for(p = &elist; (e = *p) != nil; p = &e->next)
  64                 if(e == ev){
  65                         *p = e->next;
  66                         if(e->next != nil)
  67                                 e->next->time += e->time;
  68                         return;
  69                 }
  70 }
  71
  72 void
  73 popevent(void)
  74 {
  75         Event *e;
  76         int t;
  77
  78         do{
  79                 e = elist;
  80                 t = e->time;
  81                 elist = e->next;
  82                 e->f(e->aux);
  83         }while((elist->time += t) <= 0);
  84 }
  85
  86
  87 void
  88 fifoput(int i, u32int s)
  89 {
  90         fifo *f;
  91
  92         f = sndfifo + i;
  93         if(f->level < 8)
  94                 f->d[(f->head + f->level++) & 7] = s;
  95 }
  96
  97 void
  98 fifotimer(int b, int n)
  99 {
 100         fifo *f;
 101         int i, j;
 102         extern s8int snddma[2];
 103
 104         for(i = 0; i < 2; i++){
 105                 if((b & 1<<i) == 0)
 106                         continue;
 107                 f = &sndfifo[i];
 108                 for(j = 0; j < n && f->level > 0; j++){
 109                         snddma[i] = f->d[f->head] & 0xff;
 110                         f->d[f->head] >>= 8;
 111                         if(++f->headpos == 4){
 112                                 f->head = (f->head + 1) & 7;
 113                                 f->level--;
 114                                 f->headpos = 0;
 115                         }
 116                 }
 117                 if(f->level <= 4)
 118                         dmastart(DMASOUND);
 119         }
 120 }
 121
 122 void
 123 soundcnth(u16int v)
 124 {
 125         timers[0].snd = 0;
 126         timers[1].snd = 0;
 127         if((v & 3<<8) != 0)
 128                 timers[(v >> 10) & 1].snd |= 1;
 129         if((v & 3<<12) != 0)
 130                 timers[(v >> 14) & 1].snd |= 2;
 131         if((v & 1<<11) != 0){
 132                 sndfifo[0].level = 0;
 133                 sndfifo[0].head = 0;
 134                 sndfifo[0].headpos = 0;
 135         }
 136         if((v & 1<<15) != 0){
 137                 sndfifo[1].level = 0;
 138                 sndfifo[1].head = 0;
 139                 sndfifo[1].headpos = 0;
 140         }
 141 }
 142
 143 u16int
 144 timerget(int i)
 145 {
 146         Timer *t;
 147
 148         t = &timers[i];
 149         if((*t->cnt & (COUNTUP|TIMERON)) != TIMERON)
 150                 return t->val;
 151         return t->val + (clock - t->clock >> t->sh);
 152 }
 153
 154 void
 155 timerset(int i, u16int nc)
 156 {
 157         u32int v;
 158         u16int oc;
 159         Timer *t;
 160
 161         t = &timers[i];
 162         oc = *t->cnt;
 163         if((oc & (PRESC|COUNTUP|TIMERON)) == (nc & (PRESC|COUNTUP|TIMERON)))
 164                 return;
 165         if((oc & (COUNTUP|TIMERON)) == TIMERON){
 166                 v = t->val + (clock - t->clock >> t->sh);
 167                 delevent(t);
 168         }else
 169                 v = t->val;
 170         if((oc & TIMERON) == 0 && (nc & TIMERON) != 0)
 171                 v = t->cnt[-1];
 172         if((nc & 3) != 0)
 173                 t->sh = 4 + (nc & 3) * 2;
 174         else
 175                 t->sh = 0;
 176         t->val = v;
 177         t->clock = clock & -(1 << t->sh);
 178         if((nc & (COUNTUP|TIMERON)) == TIMERON)
 179                 addevent(t, (0x10000 - t->val << t->sh) + (-clock & (1 << t->sh) - 1));
 180 }
 181
 182 void
 183 timertick(void *aux)
 184 {
 185         Timer *t;
 186         u32int v;
 187         int to;
 188         ulong clock0;
 189
 190         t = aux;
 191         clock0 = clock + t->time;
 192         t->clock = clock0 & -(1 << t->sh);
 193         t->val = -t->time >> t->sh;
 194         do{
 195                 to = 0;
 196                 do{
 197                         t->val = v = t->val + t->cnt[-1];
 198                         to++;
 199                 }while(v >= 0x10000);
 200                 if(t == aux)
 201                         addevent(t, (0x10000 - t->val << t->sh) + (-clock0 & (1 << t->sh) - 1));
 202                 if((*t->cnt & TIMERIRQ) != 0)
 203                         setif(IRQTIM0 << t->i);
 204                 if(t->snd)
 205                         fifotimer(t->snd, to);
 206                 if(++t >= timers + 4 || (*t->cnt & (COUNTUP | TIMERON)) != (COUNTUP|TIMERON))
 207                         break;
 208                 t->val = v = t->val + to;
 209         }while(v >= 0x10000);
 210 }
 211
 212 void
 213 eventinit(void)
 214 {
 215         int i;
 216         extern void hblanktick(void *);
 217
 218         for(i = 0; i < 4; i++){
 219                 timers[i].f = timertick;
 220                 timers[i].aux = &timers[i];
 221                 timers[i].i = i;
 222                 timers[i].cnt = &reg[TM0CNTH + i * 2];
 223         }
 224         evhblank.f = hblanktick;
 225         addevent(&evhblank, 240*4);
 226 }