Browsing qwx/wl3d at commit HEAD: /snd.c

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#include <u.h>
#include <libc.h>
#include <thread.h>
#include "dat.h"
#include "fns.h"

Dat *imfs;
Sfx *sfxs;
int sfxon, muson, pcmon;
int sfxlck;

enum{
	Rate = 44100,
	PcmHz = 7000,
	ImfHz = 700,
	SfxHz = 140,
	Nsamp = Rate / ImfHz * 4,
	Npsamp = Rate / PcmHz * 4,
	Mdiv = ImfHz / Tb,
	Pdiv = PcmHz / Tb,
	Nbuf = Nsamp * Mdiv,

	Rwse = 0x01,
	Rnum = 0xa0,
	Roct = 0xb0,
	Ropm = 0xbd,
	Rfed = 0xc0
};
/* channel 0, op 0-1 registers */
static uchar inst[] = {0x20, 0x23, 0x40, 0x43, 0x60, 0x63, 0x80, 0x83, 0xe0, 0xe3};
static uchar *sfxp, *sfxe, *pcm, *pcme, *imf;
static Sfx *sfxd, *pcmd;
static Dat *imfd;
static vlong stc, sdt, mdt;
static int sfd = -1;
static uchar sbuf[Nbuf];

static int h[] = {	/* stolen property coefficients */
	32767, 32766, 32764, 32760, 32755, 32749, 32741, 32731, 32721, 32708,
	32695, 32679, 32663, 32645, 32625, 32604, 32582, 32558, 32533, 32506,
	32478, 32448, 32417, 32385, 32351, 32316, 32279, 32241, 32202, 32161,
	32119, 32075, 32030, 31984, 31936, 31887, 31836, 31784, 31731, 31676,
	31620, 31563, 31504, 31444, 31383, 31320, 31256, 31191, 31124, 31056,
	30987, 30916, 30845, 30771, 30697, 30621, 30544, 30466, 30387, 30306,
	30224, 30141, 30057, 29971, 29884, 29796, 29707, 29617, 29525, 29433,
	29339, 29244, 29148, 29050, 28952, 28852, 28752, 28650, 28547, 28443,
	28338, 28232, 28125, 28017, 27908, 27797, 27686, 27574, 27461, 27346,
	27231, 27115, 26998, 26879, 26760, 26640, 26519, 26398, 26275, 26151,
	26027, 25901, 25775, 25648, 25520, 25391, 25262, 25131, 25000, 24868,
	24735, 24602, 24467, 24332, 24197, 24060, 23923, 23785, 23647, 23507,
	23368, 23227, 23086, 22944, 22802, 22659, 22515, 22371, 22226, 22081,
	21935, 21789, 21642, 21494, 21346, 21198, 21049, 20900, 20750, 20600,
	20449, 20298, 20146, 19995, 19842, 19690, 19537, 19383, 19230, 19076,
	18922, 18767, 18612, 18457, 18302, 18146, 17990, 17834, 17678, 17521,
	17365, 17208, 17051, 16894, 16737, 16579, 16422, 16264, 16106, 15949,
	15791, 15633, 15475, 15317, 15159, 15001, 14843, 14685, 14527, 14369,
	14212, 14054, 13896, 13739, 13581, 13424, 13266, 13109, 12952, 12795,
	12639, 12482, 12326, 12170, 12014, 11858, 11703, 11548, 11393, 11238,
	11084, 10929, 10776, 10622, 10469, 10316, 10164, 10011, 9860, 9708,
	9557, 9407, 9256, 9106, 8957, 8808, 8659, 8511, 8364, 8216, 8070,
	7924, 7778, 7633, 7488, 7344, 7200, 7057, 6914, 6773, 6631, 6490,
	6350, 6210, 6071, 5933, 5795, 5658, 5521, 5385, 5250, 5115, 4981,
	4848, 4716, 4584, 4452, 4322, 4192, 4063, 3935, 3807, 3680, 3554,
	3429, 3304, 3180, 3057, 2935, 2813, 2692, 2572, 2453, 2335, 2217,
	2101, 1985, 1870, 1755, 1642, 1529, 1418, 1307, 1197, 1088, 979, 872,
	765, 660, 555, 451, 348, 246, 145, 44, -54, -153, -250, -347, -443,
	-537, -631, -724, -816, -908, -998, -1087, -1175, -1263, -1349, -1435,
	-1519, -1603, -1685, -1767, -1848, -1928, -2006, -2084, -2161, -2237,
	-2312, -2386, -2459, -2531, -2603, -2673, -2742, -2810, -2878, -2944,
	-3009, -3074, -3137, -3200, -3261, -3322, -3381, -3440, -3498, -3554,
	-3610, -3665, -3719, -3772, -3824, -3875, -3925, -3974, -4022, -4069,
	-4116, -4161, -4205, -4249, -4291, -4333, -4374, -4413, -4452, -4490,
	-4527, -4563, -4599, -4633, -4666, -4699, -4730, -4761, -4791, -4820,
	-4848, -4875, -4901, -4926, -4951, -4974, -4997, -5019, -5040, -5060,
	-5080, -5098, -5116, -5133, -5149, -5164, -5178, -5192, -5205, -5217,
	-5228, -5238, -5248, -5257, -5265, -5272, -5278, -5284, -5289, -5293,
	-5297, -5299, -5301, -5303, -5303, -5303, -5302, -5300, -5298, -5295,
	-5291, -5287, -5282, -5276, -5270, -5263, -5255, -5246, -5237, -5228,
	-5217, -5206, -5195, -5183, -5170, -5157, -5143, -5128, -5113, -5097,
	-5081, -5064, -5047, -5029, -5010, -4991, -4972, -4952, -4931, -4910,
	-4889, -4867, -4844, -4821, -4797, -4774, -4749, -4724, -4699, -4673,
	-4647, -4620, -4593, -4566, -4538, -4510, -4481, -4452, -4422, -4393,
	-4363, -4332, -4301, -4270, -4238, -4206, -4174, -4142, -4109, -4076,
	-4042, -4009, -3975, -3940, -3906, -3871, -3836, -3801, -3765, -3729,
	-3693, -3657, -3620, -3584, -3547, -3510, -3472, -3435, -3397, -3360,
	-3322, -3283, -3245, -3207, -3168, -3129, -3091, -3052, -3013, -2973,
	-2934, -2895, -2855, -2816, -2776, -2736, -2697, -2657, -2617, -2577,
	-2537, -2497, -2457, -2417, -2377, -2337, -2297, -2256, -2216, -2176,
	-2136, -2096, -2056, -2016, -1976, -1936, -1896, -1856, -1817, -1777,
	-1737, -1698, -1658, -1619, -1579, -1540, -1501, -1462, -1423, -1384,
	-1345, -1306, -1268, -1230, -1191, -1153, -1115, -1077, -1040, -1002,
	-965, -927, -890, -854, -817, -780, -744, -708, -672, -636, -600,
	-565, -530, -494, -460, -425, -391, -356, -322, -289, -255, -222,
	-189, -156, -123, -91, -59, -27, 4, 35, 66, 97, 127, 158, 188, 218,
	247, 277, 306, 334, 363, 391, 419, 447, 474, 501, 528, 554, 581, 606,
	632, 657, 683, 707, 732, 756, 780, 803, 827, 850, 872, 895, 917, 939,
	960, 981, 1002, 1023, 1043, 1063, 1082, 1102, 1121, 1139, 1158, 1176,
	1194, 1211, 1228, 1245, 1262, 1278, 1294, 1309, 1325, 1340, 1354,
	1369, 1383, 1397, 1410, 1423, 1436, 1448, 1461, 1473, 1484, 1496,
	1507, 1517, 1528, 1538, 1548, 1557, 1566, 1575, 1584, 1592, 1600,
	1608, 1616, 1623, 1630, 1636, 1643, 1649, 1654, 1660, 1665, 1670,
	1675, 1679, 1683, 1687, 1690, 1694, 1697, 1700, 1702, 1704, 1706,
	1708, 1709, 1711, 1712, 1712, 1713, 1713, 1713, 1713, 1712, 1711,
	1710, 1709, 1708, 1706, 1704, 1702, 1700, 1697, 1694, 1691, 1688,
	1685, 1681, 1677, 1673, 1669, 1664, 1660, 1655, 1650, 1644, 1639,
	1633, 1627, 1621, 1615, 1609, 1602, 1596, 1589, 1582, 1575, 1567,
	1560, 1552, 1544, 1536, 1528, 1520, 1511, 1503, 1494, 1485, 1476,
	1467, 1458, 1448, 1439, 1429, 1419, 1409, 1399, 1389, 1379, 1368,
	1358, 1347, 1337, 1326, 1315, 1304, 1293, 1282, 1271, 1260, 1248,
	1237, 1225, 1213, 1202, 1190, 1178, 1166, 1154, 1142, 1130, 1118,
	1106, 1094, 1081, 1069, 1057, 1044, 1032, 1019, 1007, 994, 981, 969,
	956, 943, 931, 918, 905, 892, 879, 867, 854, 841, 828, 815, 802, 790,
	777, 764, 751, 738, 725, 713, 700, 687, 674, 662, 649, 636, 623, 611,
	598, 585, 573, 560, 548, 535, 523, 510, 498, 486, 473, 461, 449, 437,
	425, 413, 401, 389, 377, 365, 353, 341, 330, 318, 307, 295, 284, 272,
	261, 250, 239, 228, 217, 206, 195, 184, 173, 163, 152, 141, 131, 121,
	110, 100, 90, 80, 70, 60, 51, 41, 31, 22, 12, 3, -5, -14, -23, -32,
	-41, -50, -59, -67, -76, -84, -93, -101, -109, -117, -125, -133, -140,
	-148, -156, -163, -170, -178, -185, -192, -199, -206, -212, -219,
	-226, -232, -239, -245, -251, -257, -263, -269, -275, -280, -286,
	-291, -297, -302, -307, -312, -317, -322, -327, -332, -336, -341,
	-345, -349, -354, -358, -362, -366, -369, -373, -377, -380, -384,
	-387, -390, -394, -397, -400, -402, -405, -408, -411, -413, -416,
	-418, -420, -422, -424, -426, -428, -430, -432, -433, -435, -436,
	-438, -439, -440, -442, -443, -444, -445, -445, -446, -447, -447,
	-448, -448, -449, -449, -449, -449, -449, -449, -449, -449, -449,
	-449, -449, -448, -448, -447, -447, -446, -445, -444, -443, -443,
	-442, -441, -440, -438, -437, -436, -435, -433, -432, -430, -429,
	-427, -426, -424, -422, -420, -419, -417, -415, -413, -411, -409,
	-407, -405, -403, -400, -398, -396, -393, -391, -389, -386, -384,
	-381, -379, -376, -374, -371, -368, -366, -363, -360, -357, -355,
	-352, -349, -346, -343, -340, -337, -334, -331, -328, -325, -322,
	-319, -316, -313, -310, -307, -304, -301, -298, -294, -291, -288,
	-285, -282, -278, -275, -272, -269, -265, -262, -259, -256, -252,
	-249, -246, -243, -239, -236, -233, -230, -226, -223, -220, -217,
	-213, -210, -207, -204, -200, -197, -194, -191, -187, -184, -181,
	-178, -175, -172, -168, -165, -162, -159, -156, -153, -150, -147,
	-143, -140, -137, -134, -131, -128, -125, -122, -120, -117, -114,
	-111, -108, -105, -102, -99, -97, -94, -91, -88, -86, -83, -80, -78,
	-75, -72, -70, -67, -65, -62, -59, -57, -55, -52, -50, -47, -45, -43,
	-40, -38, -36, -33, -31, -29, -27, -25, -22, -20, -18, -16, -14, -12,
	-10, -8, -6, -4, -2, 0, 0, 2, 4, 6, 8, 9, 11, 13, 14, 16, 17, 19, 21,
	22, 24, 25, 27, 28, 29, 31, 32, 33, 35, 36, 37, 38, 40, 41, 42, 43,
	44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59,
	59, 60, 61, 62, 62, 63, 63, 64, 64, 65, 66, 66, 66, 67, 67, 68, 68,
	69, 69, 69, 70, 70, 70, 70, 71, 71, 71, 71, 71, 72, 72, 72, 72, 72,
	72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72,
	72, 71, 71, 71, 71, 71, 70, 70, 70, 70, 69, 69, 69, 69, 68, 68, 68,
	67, 67, 67, 66, 66, 66, 65, 65, 64, 64, 64, 63, 63, 62, 62, 62, 61,
	61, 60, 60, 59, 59, 58, 58, 58, 57, 57, 56, 56, 55, 55, 54, 54, 53,
	53, 52, 52, 51, 51, 50, 50, 49, 48, 48, 47, 47, 46, 46, 45, 45, 44,
	44, 43, 43, 42, 42, 41, 41, 40, 39, 39, 38, 38, 37, 37, 36, 36, 35,
	35, 34, 34, 33, 33, 32, 32, 31, 31, 30, 30, 29, 29, 28, 28, 27, 27,
	26, 26, 25, 25, 24, 24, 23, 23, 23, 22, 22, 21, 21, 20, 20, 20, 19,
	19, 18, 18, 17, 17, 17, 16, 16, 15, 15, 15, 14, 14, 14, 13, 13, 12,
	12, 12, 11, 11, 11, 10, 10, 10, 9, 9, 9, 9, 8, 8, 8, 7, 7, 7, 7, 6, 6,
	6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 1, 1, 1,
	1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -2, -2, -2, -2, -2,
	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
	-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
	-2, -2, -2, -2, -2, -2, -2, -2, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
};
enum{
	Nl = 8,		/* 2^Nl samples per zero crossing in fir */
	Nη = 8,		/* phase bits for filter interpolation */
	Np = Nl+Nη,	/* phase bits (fract of fixed point) */
	TΔ = ((uvlong)PcmHz<<Np) / Rate,
	One = 1<<Np,
	LΔ = 1<<Np,
	Le = nelem(h)<<Nη,
	Lscale = 13128,
	Nextra = 1 + (Le / LΔ),
	Npbuf = Nextra*2 + (Nsamp - 1)
};
static int hΔ[nelem(h)], xb[Npbuf], xbi;
static ulong xt;

static u8int ratt[][30] = {
	{8,8,8,8,8,8,8,7,7,7,7,7,7,6,0,0,0,0,0,1,3,5,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,7,7,7,7,7,6,4,0,0,0,0,0,2,4,6,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,7,7,7,7,6,6,4,1,0,0,0,1,2,4,6,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,7,7,7,7,6,5,4,2,1,0,1,2,3,5,7,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,7,7,7,6,5,4,3,2,2,3,3,5,6,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,7,7,7,6,6,5,4,4,4,4,5,6,7,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,7,7,7,6,6,5,5,5,6,6,7,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,7,7,7,6,6,7,7,8,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{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},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8}
}, latt[][30] = {
	{8,8,8,8,8,8,8,8,5,3,1,0,0,0,0,0,6,7,7,7,7,7,7,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,6,4,2,0,0,0,0,0,4,6,7,7,7,7,7,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,6,4,2,1,0,0,0,1,4,6,6,7,7,7,7,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,7,5,3,2,1,0,1,2,4,5,6,7,7,7,7,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,6,5,3,3,2,2,3,4,5,6,7,7,7,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,7,6,5,4,4,4,4,5,6,6,7,7,7,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,7,6,6,5,5,5,6,6,7,7,7,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,7,7,6,6,7,7,7,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{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},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8},
	{8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8}
};
static int atton, attx, atty, lvol, rvol;

static void
stopal(void)
{
	if(sfxd == nil)
		return;
	opl2wr(Roct, 0);
	sfxp = sfxe = nil;
	sfxd = nil;
}

static void
imfcmd(void)
{
	int r, v, dt;
	uchar *u;

	dt = 0;
	while(dt == 0){
		u = imf;
		r = u[0];
		v = u[1];
		dt = u[3]<<8 | u[2];
		opl2wr(r, v);
		imf += 4;
		if(imf >= imfd->e)
			imf = imfd->p;
	}
	mdt = stc + dt;
}

static void
alcmd(void)
{
	int v;

	if(sfxp >= sfxe){
		stopal();
		return;
	}
	v = *sfxp++;
	if(v != 0){
		opl2wr(Rnum, v);
		opl2wr(Roct, sfxd->blk);
	}else
		opl2wr(Roct, 0);
	sdt = stc + ImfHz / SfxHz;
}

/* this spins constantly even when there's no music being played continuously,
 * in essence only because some sound effects need an echo to play correctly.
 * it sucks. */
static int
opl2step(void)
{
	uchar *p;

	if(!muson && !sfxon)
		return -1;
	p = sbuf;
	while(p < sbuf + sizeof sbuf){
		if(stc == sdt && sfxd != nil)
			alcmd();
		if(stc == mdt && imfd != nil)
			imfcmd();
		p = opl2out(p, Nsamp);
		stc++;
	}
	return 0;
}

/* stolen property cargocult upsampling */
static void
filter(uchar *s)
{
	ulong l, p, i;
	int *x, o, a;
	s16int m;
	vlong v;

	v = 0;
	x = &xb[xt>>Np];	/* left side */
	l = p = xt & (1<<Np)-1;
	while(l < Le){
		i = l >> Nη;
		a = ((int)(l & (1<<Nη)-1) * hΔ[i] >> Nη) + h[i];
		v += (vlong)*(--x) * a;
		l += LΔ;
	}
	x = &xb[xt>>Np];	/* right side */
	l = One-p & (1<<Np)-1;
	if(l == 0)	/* h[0] was already summed above if p == 0 */
		l += LΔ;
	while(l < Le){
		i = l >> Nη;
		a = ((int)(l & (1<<Nη)-1) * hΔ[i] >> Nη) + h[i];
		v += (vlong)*x++ * a;
		l += LΔ;
	}
	v >>= 2;	/* scale */
	v *= Lscale;
	v >>= 27;

	m = s[0] | s[1] << 8;
	o = (s32int)(v >> 16) * lvol / 16 + m;
	if(o > 32767)
		o = 32767;
	else if(o < -32768)
		o = -32768;
	s[0] = o;
	s[1] = o >> 8;
	o = (s32int)(v >> 16) * rvol / 16 + m;
	if(o > 32767)
		o = 32767;
	else if(o < -32768)
		o = -32768;
	s[2] = o;
	s[3] = o >> 8;
}

static void
resample(uchar *p, int n)
{
	int i, s;
	uchar *b;
	ulong e;

	b = sbuf;
more:
	do{
		for(i=xbi; n>0 && i<Npbuf; n--, i++)
			xb[i] = ((uint)*p++ << 24) - 0x7fffffff;
		xbi = i;
		if(i < 2 * Nextra)	/* minimum for filter */
			break;
		e = i - Nextra << Np;
		while(xt < e){	/* process buffer and mix */
			if(b >= sbuf + nelem(sbuf)){
				n = 0;
				break;
			}
			filter(b);
			b += 4;
			xt += TΔ;
		}
		e = xt >> Np;
		if(e >= Npbuf - Nextra){	/* wrap at eob */
			xt = xt - (e << Np) + (Nextra << Np);
			s = (xt >> Np) - Nextra;
			e -= Nextra;
			i -= e;
			if(i > 0){
				memmove(xb + s, xb + e, i * sizeof i);
				s += i;
			}
			xbi = s;
		}
	}while(n > 0);
	if(b < sbuf + nelem(sbuf) && p < pcme){
		n += (b - sbuf) / Npsamp;
		goto more;
	}
	pcm = p;
}

static void
setvol(void)
{
	int x, y, ax, ay;
	s32int f;

	if(!atton){
		lvol = rvol = 16;
		return;
	}
	ax = attx - vw.x;
	ay = atty - vw.y;
	f = ffs(ax, vw.cos);
	x = f - ffs(ay, vw.sin) >> Dtlshift;
	f = ffs(ax, vw.sin);
	y = f + ffs(ay, vw.cos) >> Dtlshift;
	if(x < 0)
		x = -x;
	if(x >= nelem(latt))
		x = nelem(latt) - 1;
	if(y < -nelem(latt))
		y = -nelem(latt);
	else if(y >= nelem(latt))
		y = nelem(latt) - 1;
	lvol = 16 - latt[x][nelem(latt)+y];
	rvol = 16 - ratt[x][nelem(latt)+y];
}

static void
pcmstep(void)
{
	uchar *e, *p;

	p = pcm;
	e = pcme;
	if(p == e)
		return;
	if(p + Pdiv < e)
		e = p + Pdiv;
	setvol();
	resample(p, e-p);
}

void
sndstep(void)
{
	if(sfd < 0)
		return;
	if(opl2step() < 0){
		if(!pcmon)
			return;
		memset(sbuf, 0, sizeof sbuf);
	}
	pcmstep();
	if(!nosleep)
		write(sfd, sbuf, sizeof sbuf);
}

void
stopsfx(void)
{
	if(sfd < 0)
		return;
	stopal();
	pcm = pcme = nil;
	pcmd = nil;
}

int
lastsfx(void)
{
	if(pcm < pcme)
		return pcmd - sfxs;
	else if(sfxd != nil)
		return sfxd - sfxs;
	return -1;
}

void
sfxatt(int n, int att, int x, int y)
{
	Sfx *s;
	uchar *r, *i;

	if(sfd < 0 || sfxlck)
		return;
	s = sfxs+n;
	if(pcmon && s->pcm != nil){
		if(pcm < pcme && s->pri < pcmd->pri)
			return;
		pcmd = s;
		pcm = s->pcm->p;
		pcme = s->pcm->e;
		xbi = Nextra;
		xt = Nextra << Np;
		if(atton = att){
			attx = x;
			atty = y;
		}
	}else if(sfxon){
		if(sfxd != nil && s->pri < sfxd->pri)
			return;
		stopal();
		sfxd = s;
		sfxp = s->p;
		sfxe = s->e;
		sdt = stc;
		i = s->inst;
		r = inst;
		while(r < inst + sizeof inst)
			opl2wr(*r++, *i++);
	}
}

void
sfx(int n)
{
	sfxatt(n, 0, 0, 0);
}

void
stopmus(void)
{
	int i;

	if(sfd < 0)
		return;
	stopsfx();
	if(!muson && !sfxon)
		return;
	for(i=Roct+1; i<Roct+9; i++)
		opl2wr(i, 0);
	imf = nil;
	imfd = nil;
}

void
mus(int n)
{
	Dat *d;

	d = imfs+n;
	if(sfd < 0 || !muson || d == imfd)
		return;
	stopmus();
	mdt = stc;
	imfd = d;
	imf = d->p;
}

void
initsnd(void)
{
	int n, fd;

	fd = open("/dev/audio", OWRITE);
	if(fd < 0){
		fprint(2, "initsnd: %r\n");
		return;
	}
	opl2init(Rate);
	opl2wr(Rwse, 0x20);
	opl2wr(Ropm, 0);
	opl2wr(Rfed, 0);
	for(n=0; n<nelem(hΔ)-1; n++)
		hΔ[n] = h[n+1] - h[n];
	sfd = fd;
}