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Diffstat (limited to 'plugins/wma/libwma/wmafixed.c')
| -rw-r--r-- | plugins/wma/libwma/wmafixed.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/plugins/wma/libwma/wmafixed.c b/plugins/wma/libwma/wmafixed.c new file mode 100644 index 00000000..01326150 --- /dev/null +++ b/plugins/wma/libwma/wmafixed.c @@ -0,0 +1,222 @@ +/**************************************************************************** + * __________ __ ___. + * Open \______ \ ____ ____ | | _\_ |__ _______ ___ + * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / + * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < + * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ + * \/ \/ \/ \/ \/ + * + * Copyright (C) 2007 Michael Giacomelli + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ****************************************************************************/ + +#include "wmadec.h" +#include "wmafixed.h" + +fixed64 IntTo64(int x){ + fixed64 res = 0; + unsigned char *p = (unsigned char *)&res; + +#ifdef ROCKBOX_BIG_ENDIAN + p[5] = x & 0xff; + p[4] = (x & 0xff00)>>8; + p[3] = (x & 0xff0000)>>16; + p[2] = (x & 0xff000000)>>24; +#else + p[2] = x & 0xff; + p[3] = (x & 0xff00)>>8; + p[4] = (x & 0xff0000)>>16; + p[5] = (x & 0xff000000)>>24; +#endif + return res; +} + +int IntFrom64(fixed64 x) +{ + int res = 0; + unsigned char *p = (unsigned char *)&x; + +#ifdef ROCKBOX_BIG_ENDIAN + res = p[5] | (p[4]<<8) | (p[3]<<16) | (p[2]<<24); +#else + res = p[2] | (p[3]<<8) | (p[4]<<16) | (p[5]<<24); +#endif + return res; +} + +fixed32 Fixed32From64(fixed64 x) +{ + return x & 0xFFFFFFFF; +} + +fixed64 Fixed32To64(fixed32 x) +{ + return (fixed64)x; +} + +/* + Not performance senstitive code here + +*/ + +fixed32 fixdiv32(fixed32 x, fixed32 y) +{ + fixed64 temp; + + if(x == 0) + return 0; + if(y == 0) + return 0x7fffffff; + temp = x; + temp <<= PRECISION; + return (fixed32)(temp / y); +} + +fixed64 fixdiv64(fixed64 x, fixed64 y) +{ + fixed64 temp; + + if(x == 0) + return 0; + if(y == 0) + return 0x07ffffffffffffffLL; + temp = x; + temp <<= PRECISION64; + return (fixed64)(temp / y); +} + + fixed32 fixsqrt32(fixed32 x) +{ + + unsigned long r = 0, s, v = (unsigned long)x; + +#define STEP(k) s = r + (1 << k * 2); r >>= 1; \ + if (s <= v) { v -= s; r |= (1 << k * 2); } + + STEP(15); + STEP(14); + STEP(13); + STEP(12); + STEP(11); + STEP(10); + STEP(9); + STEP(8); + STEP(7); + STEP(6); + STEP(5); + STEP(4); + STEP(3); + STEP(2); + STEP(1); + STEP(0); + + return (fixed32)(r << (PRECISION / 2)); +} + + + static const long cordic_circular_gain = 0xb2458939; /* 0.607252929 */ + + /* Table of values of atan(2^-i) in 0.32 format fractions of pi where pi = 0xffffffff / 2 */ + static const unsigned long atan_table[] = { + 0x1fffffff, /* +0.785398163 (or pi/4) */ + 0x12e4051d, /* +0.463647609 */ + 0x09fb385b, /* +0.244978663 */ + 0x051111d4, /* +0.124354995 */ + 0x028b0d43, /* +0.062418810 */ + 0x0145d7e1, /* +0.031239833 */ + 0x00a2f61e, /* +0.015623729 */ + 0x00517c55, /* +0.007812341 */ + 0x0028be53, /* +0.003906230 */ + 0x00145f2e, /* +0.001953123 */ + 0x000a2f98, /* +0.000976562 */ + 0x000517cc, /* +0.000488281 */ + 0x00028be6, /* +0.000244141 */ + 0x000145f3, /* +0.000122070 */ + 0x0000a2f9, /* +0.000061035 */ + 0x0000517c, /* +0.000030518 */ + 0x000028be, /* +0.000015259 */ + 0x0000145f, /* +0.000007629 */ + 0x00000a2f, /* +0.000003815 */ + 0x00000517, /* +0.000001907 */ + 0x0000028b, /* +0.000000954 */ + 0x00000145, /* +0.000000477 */ + 0x000000a2, /* +0.000000238 */ + 0x00000051, /* +0.000000119 */ + 0x00000028, /* +0.000000060 */ + 0x00000014, /* +0.000000030 */ + 0x0000000a, /* +0.000000015 */ + 0x00000005, /* +0.000000007 */ + 0x00000002, /* +0.000000004 */ + 0x00000001, /* +0.000000002 */ + 0x00000000, /* +0.000000001 */ + 0x00000000, /* +0.000000000 */ + }; + + /** + * Implements sin and cos using CORDIC rotation. + * + * @param phase has range from 0 to 0xffffffff, representing 0 and + * 2*pi respectively. + * @param cos return address for cos + * @return sin of phase, value is a signed value from LONG_MIN to LONG_MAX, + * representing -1 and 1 respectively. + * + * Gives at least 24 bits precision (last 2-8 bits or so are probably off) + */ + + long fsincos(unsigned long phase, fixed32 *cos) + { + int32_t x, x1, y, y1; + unsigned long z, z1; + int i; + + /* Setup initial vector */ + x = cordic_circular_gain; + y = 0; + z = phase; + + /* The phase has to be somewhere between 0..pi for this to work right */ + if (z < 0xffffffff / 4) { + /* z in first quadrant, z += pi/2 to correct */ + x = -x; + z += 0xffffffff / 4; + } else if (z < 3 * (0xffffffff / 4)) { + /* z in third quadrant, z -= pi/2 to correct */ + z -= 0xffffffff / 4; + } else { + /* z in fourth quadrant, z -= 3pi/2 to correct */ + x = -x; + z -= 3 * (0xffffffff / 4); + } + + /* Each iteration adds roughly 1-bit of extra precision */ + for (i = 0; i < 31; i++) { + x1 = x >> i; + y1 = y >> i; + z1 = atan_table[i]; + + /* Decided which direction to rotate vector. Pivot point is pi/2 */ + if (z >= 0xffffffff / 4) { + x -= y1; + y += x1; + z -= z1; + } else { + x += y1; + y -= x1; + z += z1; + } + } + + if (cos) + *cos = x; + + return y; + } |