ref: 83aa7ba70933335cd579b560a793b7741d5e3931
dir: /sys/src/games/gba/ev.c/
#include <u.h> #include <libc.h> #include <thread.h> #include "dat.h" #include "fns.h" typedef struct { u16int *cnt; Event; u16int val; int clock; u8int i, sh, snd; } Timer; typedef struct fifo fifo; struct fifo { u32int d[8]; u8int head, level, headpos; }; fifo sndfifo[2]; Event *elist; Timer timers[4]; Event evhblank; extern Event evsamp; Event *events[NEVENT] = {&timers[0].Event, &timers[1].Event, &timers[2].Event, &timers[3].Event, &evhblank, &evsamp}; Var evvars[] = { VAR(clock), ARR(sndfifo[0].d), VAR(sndfifo[0].head), VAR(sndfifo[0].level), VAR(sndfifo[0].headpos), ARR(sndfifo[1].d), VAR(sndfifo[1].head), VAR(sndfifo[1].level), VAR(sndfifo[1].headpos), VAR(timers[0].val), VAR(timers[0].clock), VAR(timers[0].sh), VAR(timers[0].snd), VAR(timers[1].val), VAR(timers[1].clock), VAR(timers[1].sh), VAR(timers[1].snd), VAR(timers[2].val), VAR(timers[2].clock), VAR(timers[2].sh), VAR(timers[2].snd), VAR(timers[3].val), VAR(timers[3].clock), VAR(timers[3].sh), VAR(timers[3].snd), {nil, 0, 0}, }; void addevent(Event *ev, int time) { Event **p, *e; int t; t = time; for(p = &elist; (e = *p) != nil; p = &e->next){ if(t < e->time){ e->time -= t; break; } t -= e->time; } ev->next = e; ev->time = t; *p = ev; } void delevent(Event *ev) { Event **p, *e; for(p = &elist; (e = *p) != nil; p = &e->next) if(e == ev){ *p = e->next; if(e->next != nil) e->next->time += e->time; return; } } void popevent(void) { Event *e; int t; do{ e = elist; t = e->time; elist = e->next; e->f(e->aux); }while((elist->time += t) <= 0); } void fifoput(int i, u32int s) { fifo *f; f = sndfifo + i; if(f->level < 8) f->d[(f->head + f->level++) & 7] = s; } void fifotimer(int b, int n) { fifo *f; int i, j; extern s8int snddma[2]; for(i = 0; i < 2; i++){ if((b & 1<<i) == 0) continue; f = &sndfifo[i]; for(j = 0; j < n && f->level > 0; j++){ snddma[i] = f->d[f->head] & 0xff; f->d[f->head] >>= 8; if(++f->headpos == 4){ f->head = (f->head + 1) & 7; f->level--; f->headpos = 0; } } if(f->level <= 4) dmastart(DMASOUND); } } void soundcnth(u16int v) { timers[0].snd = 0; timers[1].snd = 0; if((v & 3<<8) != 0) timers[(v >> 10) & 1].snd |= 1; if((v & 3<<12) != 0) timers[(v >> 14) & 1].snd |= 2; if((v & 1<<11) != 0){ sndfifo[0].level = 0; sndfifo[0].head = 0; sndfifo[0].headpos = 0; } if((v & 1<<15) != 0){ sndfifo[1].level = 0; sndfifo[1].head = 0; sndfifo[1].headpos = 0; } } u16int timerget(int i) { Timer *t; t = &timers[i]; if((*t->cnt & (COUNTUP|TIMERON)) != TIMERON) return t->val; return t->val + (clock - t->clock >> t->sh); } void timerset(int i, u16int nc) { u32int v; u16int oc; Timer *t; t = &timers[i]; oc = *t->cnt; if((oc & (PRESC|COUNTUP|TIMERON)) == (nc & (PRESC|COUNTUP|TIMERON))) return; if((oc & (COUNTUP|TIMERON)) == TIMERON){ v = t->val + (clock - t->clock >> t->sh); delevent(t); }else v = t->val; if((oc & TIMERON) == 0 && (nc & TIMERON) != 0) v = t->cnt[-1]; if((nc & 3) != 0) t->sh = 4 + (nc & 3) * 2; else t->sh = 0; t->val = v; t->clock = clock & -(1 << t->sh); if((nc & (COUNTUP|TIMERON)) == TIMERON) addevent(t, (0x10000 - t->val << t->sh) + (-clock & (1 << t->sh) - 1)); } void timertick(void *aux) { Timer *t; u32int v; int to; ulong clock0; t = aux; clock0 = clock + t->time; t->clock = clock0 & -(1 << t->sh); t->val = -t->time >> t->sh; do{ to = 0; do{ t->val = v = t->val + t->cnt[-1]; to++; }while(v >= 0x10000); if(t == aux) addevent(t, (0x10000 - t->val << t->sh) + (-clock0 & (1 << t->sh) - 1)); if((*t->cnt & TIMERIRQ) != 0) setif(IRQTIM0 << t->i); if(t->snd) fifotimer(t->snd, to); if(++t >= timers + 4 || (*t->cnt & (COUNTUP | TIMERON)) != (COUNTUP|TIMERON)) break; t->val = v = t->val + to; }while(v >= 0x10000); } void eventinit(void) { int i; extern void hblanktick(void *); for(i = 0; i < 4; i++){ timers[i].f = timertick; timers[i].aux = &timers[i]; timers[i].i = i; timers[i].cnt = ®[TM0CNTH + i * 2]; } evhblank.f = hblanktick; addevent(&evhblank, 240*4); }