| /**************************************************************************** |
| * __________ __ ___. |
| * Open \______ \ ____ ____ | | _\_ |__ _______ ___ |
| * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / |
| * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < |
| * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ |
| * \/ \/ \/ \/ \/ |
| * |
| * Copyright (C) 2006 Michael Giacomelli |
| * |
| * All files in this archive are subject to the GNU General Public License. |
| * See the file COPYING in the source tree root for full license agreement. |
| * |
| * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY |
| * KIND, either express or implied. |
| * |
| ****************************************************************************/ |
| |
| #include "wmadec.h" |
| #include "wmafixed.h" |
| #include <codecs.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 |
| |
| */ |
| |
| |
| fixed64 fixmul64byfixed(fixed64 x, fixed32 y) |
| { |
| |
| //return x * y; |
| return (x * y); |
| // return (fixed64) fixmul32(Fixed32From64(x),y); |
| } |
| |
| |
| 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)); |
| } |
| |
| |
| |
| /* Inverse gain of circular cordic rotation in s0.31 format. */ |
| 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 */ |
| }; |
| |
| |
| /* |
| |
| Below here functions do not use standard fixed precision! |
| */ |
| |
| |
| /** |
| * 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; |
| } |
| |
| |