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Release 4.15 include/linux/fixp-arith.h

Directory: include/linux
#ifndef _FIXP_ARITH_H

#define _FIXP_ARITH_H

#include <linux/math64.h>

/*
 * Simplistic fixed-point arithmetics.
 * Hmm, I'm probably duplicating some code :(
 *
 * Copyright (c) 2002 Johann Deneux
 */

/*
 * 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 program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Should you need to contact me, the author, you can do so by
 * e-mail - mail your message to <johann.deneux@gmail.com>
 */

#include <linux/types.h>


static const s32 sin_table[] = {
	0x00000000, 0x023be165, 0x04779632, 0x06b2f1d2, 0x08edc7b6, 0x0b27eb5c,
	0x0d61304d, 0x0f996a26, 0x11d06c96, 0x14060b67, 0x163a1a7d, 0x186c6ddd,
	0x1a9cd9ac, 0x1ccb3236, 0x1ef74bf2, 0x2120fb82, 0x234815ba, 0x256c6f9e,
	0x278dde6e, 0x29ac379f, 0x2bc750e8, 0x2ddf003f, 0x2ff31bdd, 0x32037a44,
	0x340ff241, 0x36185aee, 0x381c8bb5, 0x3a1c5c56, 0x3c17a4e7, 0x3e0e3ddb,
	0x3fffffff, 0x41ecc483, 0x43d464fa, 0x45b6bb5d, 0x4793a20f, 0x496af3e1,
	0x4b3c8c11, 0x4d084650, 0x4ecdfec6, 0x508d9210, 0x5246dd48, 0x53f9be04,
	0x55a6125a, 0x574bb8e5, 0x58ea90c2, 0x5a827999, 0x5c135399, 0x5d9cff82,
	0x5f1f5ea0, 0x609a52d1, 0x620dbe8a, 0x637984d3, 0x64dd894f, 0x6639b039,
	0x678dde6d, 0x68d9f963, 0x6a1de735, 0x6b598ea1, 0x6c8cd70a, 0x6db7a879,
	0x6ed9eba0, 0x6ff389de, 0x71046d3c, 0x720c8074, 0x730baeec, 0x7401e4bf,
	0x74ef0ebb, 0x75d31a5f, 0x76adf5e5, 0x777f903b, 0x7847d908, 0x7906c0af,
	0x79bc384c, 0x7a6831b8, 0x7b0a9f8c, 0x7ba3751c, 0x7c32a67c, 0x7cb82884,
	0x7d33f0c8, 0x7da5f5a3, 0x7e0e2e31, 0x7e6c924f, 0x7ec11aa3, 0x7f0bc095,
	0x7f4c7e52, 0x7f834ecf, 0x7fb02dc4, 0x7fd317b3, 0x7fec09e1, 0x7ffb025e,
	0x7fffffff
};

/**
 * __fixp_sin32() returns the sin of an angle in degrees
 *
 * @degrees: angle, in degrees, from 0 to 360.
 *
 * The returned value ranges from -0x7fffffff to +0x7fffffff.
 */

static inline s32 __fixp_sin32(int degrees) { s32 ret; bool negative = false; if (degrees > 180) { negative = true; degrees -= 180; } if (degrees > 90) degrees = 180 - degrees; ret = sin_table[degrees]; return negative ? -ret : ret; }

Contributors

PersonTokensPropCommitsCommitProp
Mauro Carvalho Chehab3659.02%120.00%
Vojtech Pavlik2337.70%240.00%
Anssi Hannula11.64%120.00%
Zinx Verituse11.64%120.00%
Total61100.00%5100.00%

/** * fixp_sin32() returns the sin of an angle in degrees * * @degrees: angle, in degrees. The angle can be positive or negative * * The returned value ranges from -0x7fffffff to +0x7fffffff. */
static inline s32 fixp_sin32(int degrees) { degrees = (degrees % 360 + 360) % 360; return __fixp_sin32(degrees); }

Contributors

PersonTokensPropCommitsCommitProp
Mauro Carvalho Chehab1553.57%133.33%
Vojtech Pavlik1242.86%133.33%
Zinx Verituse13.57%133.33%
Total28100.00%3100.00%

/* cos(x) = sin(x + 90 degrees) */ #define fixp_cos32(v) fixp_sin32((v) + 90) /* * 16 bits variants * * The returned value ranges from -0x7fff to 0x7fff */ #define fixp_sin16(v) (fixp_sin32(v) >> 16) #define fixp_cos16(v) (fixp_cos32(v) >> 16) /** * fixp_sin32_rad() - calculates the sin of an angle in radians * * @radians: angle, in radians * @twopi: value to be used for 2*pi * * Provides a variant for the cases where just 360 * values is not enough. This function uses linear * interpolation to a wider range of values given by * twopi var. * * Experimental tests gave a maximum difference of * 0.000038 between the value calculated by sin() and * the one produced by this function, when twopi is * equal to 360000. That seems to be enough precision * for practical purposes. * * Please notice that two high numbers for twopi could cause * overflows, so the routine will not allow values of twopi * bigger than 1^18. */
static inline s32 fixp_sin32_rad(u32 radians, u32 twopi) { int degrees; s32 v1, v2, dx, dy; s64 tmp; /* * Avoid too large values for twopi, as we don't want overflows. */ BUG_ON(twopi > 1 << 18); degrees = (radians * 360) / twopi; tmp = radians - (degrees * twopi) / 360; degrees = (degrees % 360 + 360) % 360; v1 = __fixp_sin32(degrees); v2 = fixp_sin32(degrees + 1); dx = twopi / 360; dy = v2 - v1; tmp *= dy; return v1 + div_s64(tmp, dx); }

Contributors

PersonTokensPropCommitsCommitProp
Mauro Carvalho Chehab10289.47%133.33%
Vojtech Pavlik119.65%133.33%
Zinx Verituse10.88%133.33%
Total114100.00%3100.00%

/* cos(x) = sin(x + pi/2 radians) */ #define fixp_cos32_rad(rad, twopi) \ fixp_sin32_rad(rad + twopi / 4, twopi) #endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Mauro Carvalho Chehab33274.44%114.29%
Vojtech Pavlik10523.54%228.57%
Zinx Verituse40.90%114.29%
Anssi Hannula30.67%114.29%
Arjan van de Ven10.22%114.29%
Johann Deneux10.22%114.29%
Total446100.00%7100.00%
Directory: include/linux
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