tabinit.c

xmms-1.2.10.tar.gz学习使用的就下吧

#include <stdlib.h>

#include "mpg123.h"

real mpg123_decwin[512 + 32];
static real cos64[16], cos32[8], cos16[4], cos8[2], cos4[1];
real *mpg123_pnts[] = {cos64, cos32, cos16, cos8, cos4};

static unsigned char *mpg123_conv16to8_buf = NULL;
unsigned char *mpg123_conv16to8;

static long intwinbase[] =
{
	0, -1, -1, -1, -1, -1, -1, -2, -2, -2,
	-2, -3, -3, -4, -4, -5, -5, -6, -7, -7,
	-8, -9, -10, -11, -13, -14, -16, -17, -19, -21,
	-24, -26, -29, -31, -35, -38, -41, -45, -49, -53,
	-58, -63, -68, -73, -79, -85, -91, -97, -104, -111,
	-117, -125, -132, -139, -147, -154, -161, -169, -176, -183,
	-190, -196, -202, -208, -213, -218, -222, -225, -227, -228,
	-228, -227, -224, -221, -215, -208, -200, -189, -177, -163,
	-146, -127, -106, -83, -57, -29, 2, 36, 72, 111,
	153, 197, 244, 294, 347, 401, 459, 519, 581, 645,
	711, 779, 848, 919, 991, 1064, 1137, 1210, 1283, 1356,
	1428, 1498, 1567, 1634, 1698, 1759, 1817, 1870, 1919, 1962,
	2001, 2032, 2057, 2075, 2085, 2087, 2080, 2063, 2037, 2000,
	1952, 1893, 1822, 1739, 1644, 1535, 1414, 1280, 1131, 970,
	794, 605, 402, 185, -45, -288, -545, -814, -1095, -1388,
	-1692, -2006, -2330, -2663, -3004, -3351, -3705, -4063, -4425, -4788,
	-5153, -5517, -5879, -6237, -6589, -6935, -7271, -7597, -7910, -8209,
	-8491, -8755, -8998, -9219, -9416, -9585, -9727, -9838, -9916, -9959,
	-9966, -9935, -9863, -9750, -9592, -9389, -9139, -8840, -8492, -8092,
	-7640, -7134, -6574, -5959, -5288, -4561, -3776, -2935, -2037, -1082,
	-70, 998, 2122, 3300, 4533, 5818, 7154, 8540, 9975, 11455,
	12980, 14548, 16155, 17799, 19478, 21189, 22929, 24694, 26482, 28289,
	30112, 31947, 33791, 35640, 37489, 39336, 41176, 43006, 44821, 46617,
	48390, 50137, 51853, 53534, 55178, 56778, 58333, 59838, 61289, 62684,
	64019, 65290, 66494, 67629, 68692, 69679, 70590, 71420, 72169, 72835,
	73415, 73908, 74313, 74630, 74856, 74992, 75038};

void mpg123_make_decode_tables_fpu(long scaleval);
void mpg123_make_decode_tables_mmx(long scaleval);

void mpg123_make_decode_tables_fpu(long scaleval)
{
	int i, j;
	real *table, *costab;

	for (i = 0; i < 5; i++)
	{
		int kr = 0x10 >> i;
		int divv = 0x40 >> i;
		costab = mpg123_pnts[i];
		for (j = 0; j < kr; j++)
			costab[j] = 1.0 / (2.0 * cos(M_PI * ((double) j * 2.0 + 1.0) / (double) divv));
	}

	table = mpg123_decwin;
	scaleval = -scaleval;
	for (i = 0, j = 0; i < 256; i++, j++, table += 32)
	{
		if (table < mpg123_decwin + 512 + 16)
			table[16] = table[0] = (double) intwinbase[j] / 65536.0 * (double) scaleval;
		if (i % 32 == 31)
			table -= 1023;
		if (i % 64 == 63)
			scaleval = -scaleval;
	}

	for ( /* i=256 */ ; i < 512; i++, j--, table += 32)
	{
		if (table < mpg123_decwin + 512 + 16)
			table[16] = table[0] = (double) intwinbase[j] / 65536.0 * (double) scaleval;
		if (i % 32 == 31)
			table -= 1023;
		if (i % 64 == 63)
			scaleval = -scaleval;
	}
}

#ifdef USE_SIMD

gint16 mpg123_decwins[(512 + 32) * 2];

void mpg123_make_decode_tables_mmx(long scaleval)
{
	int i, j, p, a;

	scaleval = -scaleval;
	a = 1;
	for (i = 0, j = 0, p = 0; i < 512; i++, j += a, p += 32)
	{
		if (p < 512 + 16)
		{
			int val = ((gint64)intwinbase[j] * scaleval) >> 17;
			val = CLAMP(val, -32767, 32767);
			if (p < 512)
			{
				int n = 1055 - p;
				mpg123_decwins[n - 16] = val;
				mpg123_decwins[n] = val;
			}
			if (!(p & 1))
				val = -val;
			mpg123_decwins[p + 16] = val;
			mpg123_decwins[p] = val;
		}
		if (i % 32 == 31)
			p -= 1023;
		if (i % 64 == 63)
			scaleval = -scaleval;
		if (i == 256)
			a = -1;
	}
}

#else
void mpg123_make_decode_tables_mmx(long scaleval)
{
}
#endif

void mpg123_make_decode_tables(long scaleval)
{
	mpg123_make_decode_tables_fpu(scaleval);
	mpg123_make_decode_tables_mmx(scaleval);
}




void mpg123_make_conv16to8_table(void)
{
	int i;

	/*
	 * ????: 8.0 is right but on SB cards '2.0' is a better value ???
	 */

	if (!mpg123_conv16to8_buf)
	{
		mpg123_conv16to8_buf = g_malloc(8192);
		mpg123_conv16to8 = mpg123_conv16to8_buf + 4096;
	}

	for (i = -4096; i < 4096; i++)
	{
		mpg123_conv16to8[i] = (i >> 5) + 128;
	}
}