ref: 0a7279b3aff262493e5c80f17a540a4b5e8987a5
dir: /sys/src/games/md/ym.c/
#include <u.h> #include <libc.h> #include <thread.h> #include "../eui.h" #include "dat.h" #include "fns.h" u8int ym[512]; enum { MODE = 0x27, FDIV = 1048576 * 2 * 144, }; #define min(a, b) ((a)<=(b)?(a):(b)) typedef struct oper oper; typedef struct fm fm; struct oper { enum {OFF, ATTACK, DECAY, SUSTAIN, RELEASE} st; u8int *r; int env; u8int ar, sr, dr, rs, rr, mult; u16int tl, sl; u8int keyon, keyoff, rate; int det; u8int kc; u32int phi, amp, dp; int val, val0; }; struct fm { oper op[4]; u8int st, alg, en, fbs; float samp; } fms[6]; u8int ymstat; static u32int cyc; static u16int tima; static u8int timb; static short sbuf[2 * 2000], *sbufp; static int fd; static int sint[256], expt[256]; static void timers(void) { u8int m; static u8int bdiv; m = ym[0x27]; if((m & 1) != 0){ tima = (tima + 1) & 0x3ff; if(tima == 0 && (m & 4) != 0){ ymstat |= 1; tima = ym[0x24] | ym[0x25] << 8 & 0x300; } } if(++bdiv == 8){ bdiv = 0; if((m & 2) != 0){ timb++; if(timb == 0 && (m & 8) != 0){ ymstat |= 2; timb = ym[0x26]; } } } } static void calcfreq(int n) { int i, fr; fm *f; oper *p; uchar *r; static u8int det[4][32] = { {0}, {0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 8, 8, 8, 8}, {1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 8, 8, 9,10,11,12,13,14,16,16,16,16}, {2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 8, 8, 9,10,11,12,13,14,16,17,19,20,22,22,22,22} }; r = ym; f = &fms[n]; if(n >= 3){ n -= 3; r += 0x100; } fr = r[0xa0 + n] | r[0xa4 + n] << 8 & 0x3f00; for(i = 0; i < 3; i++){ p = &f->op[i]; if(n == 2 && (ym[MODE] & 0xc0) == 0x40 && i != 0) fr = r[0xa7+i] | r[0xab+i] << 8 & 0x3f00; p->kc = fr >> 9 & 0x1e; if((fr & 0x780) >= 0x380 && (fr & 0x780) != 0x400) p->kc |= 1; p->dp = ((fr & 0x7ff) << (fr >> 11)) >> 1; if((p->det & 4) != 0) p->dp -= det[p->det & 3][p->kc]; else p->dp += det[p->det][p->kc]; if(p->mult != 0) p->dp = (p->dp & 0x1ffff) * p->mult; else p->dp = (u16int)(p->dp >> 1); } } void ymwrite(u8int a, u8int v, u8int c) { int ch, i; oper *p; fm *f; ym[c ? a|0x100 : a] = v; if(a >= 0x30 && a < 0xa0){ ch = a & 3; if(ch == 3) return; ch += c; f = &fms[ch]; i = a >> 3 & 1 | a >> 1 & 2; p = &f->op[i]; switch(a & 0xf0){ case 0x30: p->mult = v & 0x0f; p->det = v >> 4 & 7; calcfreq(ch); break; case 0x40: p->tl = v << 3 & 0x3f8; break; case 0x50: p->ar = v << 1 & 0x3e; p->rs = 3 - (v >> 6); break; case 0x60: p->dr = v << 1 & 0x3e; break; case 0x70: p->sr = v << 1 & 0x3e; break; case 0x80: p->sl = v << 2 & 0x3c0; p->rr = v << 2 & 0x3c | 0x02; break; }; }else{ ch = c + (a & 3); switch(a){ case MODE: if((v & 0x10) != 0) ymstat &= ~2; if((v & 0x20) != 0) ymstat &= ~1; calcfreq(2); calcfreq(5); break; case 0x28: ch = v & 3; if(ch == 3) break; if((v & 4) != 0) ch += 3; f = &fms[ch]; for(i = 0; i < 4; i++){ p = &f->op[i]; if((v & 1<<4+i) != 0){ if(p->st == OFF || p->st == RELEASE) p->keyon++; }else if(p->st != OFF) p->keyoff++; } break; case 0xa0: case 0xa1: case 0xa2: case 0xa4: case 0xa5: case 0xa6: calcfreq(ch); break; case 0xa8: case 0xa9: case 0xaa: case 0xac: case 0xad: case 0xae: calcfreq((a & 0x100) != 0 ? 5 : 2); break; case 0xb0: case 0xb1: case 0xb2: fms[ch].alg = v & 7; fms[ch].fbs = 7 - (v >> 3 & 7); break; case 0xb4: case 0xb5: case 0xb6: fms[ch].en = v; break; } } } static void tables(void) { int i; double x; for(i = 0; i < 256; i++){ x = sin(((i << 1) + 1) * PI / 1024); x = -log(x)/log(2); sint[i] = x * 256 + 0.5; } for(i = 0; i < 256; i++){ x = pow(2, -(i+1)/256.0); expt[i] = x * 2048 + 0.5; } } void ymreset(void) { int i, j; for(i = 0; i < 6; i++){ fms[i].en = 0xc0; for(j = 0; j < 4; j++) fms[i].op[j].rs = 3; } tables(); } static u8int rate(oper *p, u8int r) { if(r == 0) return 0; r += p->kc >> p->rs; if(r > 63) return 63; return r; } static void env(oper *p) { int v, sh, ai; static u8int ait[64][8] = { {0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0}, {0,1,0,1,0,1,0,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,0,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,0,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {0,1,0,1,0,1,0,1}, {0,1,0,1,1,1,0,1}, {0,1,1,1,0,1,1,1}, {0,1,1,1,1,1,1,1}, {1,1,1,1,1,1,1,1}, {1,1,1,2,1,1,1,2}, {1,2,1,2,1,2,1,2}, {1,2,2,2,1,2,2,2}, {2,2,2,2,2,2,2,2}, {2,2,2,4,2,2,2,4}, {2,4,2,4,2,4,2,4}, {2,4,4,4,2,4,4,4}, {4,4,4,4,4,4,4,4}, {4,4,4,8,4,4,4,8}, {4,8,4,8,4,8,4,8}, {4,8,8,8,4,8,8,8}, {8,8,8,8,8,8,8,8}, {8,8,8,8,8,8,8,8}, {8,8,8,8,8,8,8,8}, {8,8,8,8,8,8,8,8}, }; if(p->keyon > 0){ p->st = ATTACK; p->rate = rate(p, p->ar); p->env = 0; p->keyon = 0; }else if(p->keyoff > 0){ p->st = RELEASE; p->rate = rate(p, p->rr); p->keyoff = 0; } if(p->rate > 0){ sh = p->rate >> 2; if(sh < 11) sh = 11 - sh; else sh = 0; if((cyc & (1 << sh) - 1) == 0){ ai = ait[p->rate][(cyc >> sh) & 7]; switch(p->st){ case ATTACK: p->env += ai * ((1024 - p->env >> 4) + 1); if(p->env >= 1024){ p->env = 0; p->st = DECAY; p->rate = rate(p, p->dr); } break; case DECAY: p->env += ai; if(p->env >= 1024) p->env = 1023; if(p->env >= p->sl){ p->st = SUSTAIN; p->rate = rate(p, p->sr); } break; case SUSTAIN: case RELEASE: p->env += ai; if(p->env >= 1024){ p->env = 1023; p->st = OFF; p->rate = 0; } break; } } } if(p->st == OFF){ p->amp = 1023; return; } v = p->env; if(p->st == ATTACK) v ^= 1023; v += p->tl; if(v > 1023) p->amp = 1023; else p->amp = v; } static void opr(oper *p, int inp) { int v, x, r; p->phi += p->dp; v = (p->phi >> 10) + inp; if((v & 0x100) != 0) v ^= 0xff; x = sint[v & 0xff] + (p->amp << 2); r = expt[x & 0xff] << 2 >> (x >> 8); p->val0 = p->val; if((v & 0x200) != 0) p->val = -r; else p->val = r; } void ymstep(void) { static int ymch, ymop, ymcyc; fm *f; oper *p; int x; f = fms + ymch; p = f->op + ymop; x = 0; if(ymop == 0){ if(f->fbs != 7) x = p->val + p->val0 >> f->fbs + 2; }else{ switch(f->alg << 4 | ymop){ default: x = p[-1].val; break; case 0x11: break; case 0x12: x = f->op[0].val + f->op[1].val; break; case 0x21: break; case 0x23: x = f->op[0].val + f->op[2].val; break; case 0x32: break; case 0x33: x = f->op[1].val + f->op[2].val; break; case 0x42: break; case 0x52: case 0x53: x = f->op[0].val; break; case 0x62: case 0x63: break; case 0x71: case 0x72: case 0x73: break; } x >>= 1; } if(ymcyc == 0) env(p); opr(p, x); if(ymop == 3){ switch(f->alg){ default: x = p->val >> 5; break; case 4: x = (f->op[1].val >> 5) + (p->val >> 5); break; case 5: case 6: x = (f->op[1].val >> 5) + (f->op[2].val >> 5) + (p->val >> 5); break; case 7: x = (f->op[0].val >> 5) + (f->op[1].val >> 5) + (f->op[2].val >> 5) + (p->val >> 5); break; } if(x > 256) x = 256; if(x < -256) x = -256; f->samp = x / 256.0; if(++ymch == 6){ ymch = 0; if(++ymcyc == 3){ cyc++; ymcyc = 0; timers(); } } ymop = 0; }else ymop++; } void audiosample(void) { int i; u8int x; float v, vl, vr; if(sbufp == nil) return; vl = vr = 0; for(i = 0; i < 6; i++){ if(i == 5 && (ym[0x2b] & 0x80) != 0) v = ym[0x2a] / 255.0; else v = fms[i].samp; x = fms[i].en; if((x & 0x80) != 0) vl += v; if((x & 0x40) != 0) vr += v; } if(sbufp < sbuf + nelem(sbuf) - 1){ *sbufp++ = vl * 5000; *sbufp++ = vr * 5000; } } int audioout(void) { int rc; if(sbufp == nil) return -1; if(sbufp == sbuf) return 0; rc = warp10 ? (sbufp - sbuf) * 2 : write(fd, sbuf, (sbufp - sbuf) * 2); if(rc > 0) sbufp -= (rc+1)/2; if(sbufp < sbuf) sbufp = sbuf; return 0; } void initaudio(void) { fd = open("/dev/audio", OWRITE); if(fd < 0) return; sbufp = sbuf; }