mirror of
https://github.com/torvalds/linux.git
synced 2024-11-23 12:42:02 +00:00
2c64e9cb0b
For better maintenance and expansion move the mathematic helpers to the separate folder. No functional change intended. Note, the int_sqrt() is not used as a part of lib, so, moved to regular obj. Link: http://lkml.kernel.org/r/20190323172531.80025-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Lee Jones <lee.jones@linaro.org> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Ray Jui <rjui@broadcom.com> [mchehab+samsung@kernel.org: fix broken doc references for div64.c and gcd.c] Link: http://lkml.kernel.org/r/734f49bae5d4052b3c25691dfefad59bea2e5843.1555580999.git.mchehab+samsung@kernel.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
93 lines
2.2 KiB
C
93 lines
2.2 KiB
C
/*
|
|
* Copyright (c) 2011 Broadcom Corporation
|
|
*
|
|
* Permission to use, copy, modify, and/or distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
|
|
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
|
|
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
|
|
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
*/
|
|
#include <linux/module.h>
|
|
#include <linux/cordic.h>
|
|
|
|
static const s32 arctan_table[] = {
|
|
2949120,
|
|
1740967,
|
|
919879,
|
|
466945,
|
|
234379,
|
|
117304,
|
|
58666,
|
|
29335,
|
|
14668,
|
|
7334,
|
|
3667,
|
|
1833,
|
|
917,
|
|
458,
|
|
229,
|
|
115,
|
|
57,
|
|
29
|
|
};
|
|
|
|
/*
|
|
* cordic_calc_iq() - calculates the i/q coordinate for given angle
|
|
*
|
|
* theta: angle in degrees for which i/q coordinate is to be calculated
|
|
* coord: function output parameter holding the i/q coordinate
|
|
*/
|
|
struct cordic_iq cordic_calc_iq(s32 theta)
|
|
{
|
|
struct cordic_iq coord;
|
|
s32 angle, valtmp;
|
|
unsigned iter;
|
|
int signx = 1;
|
|
int signtheta;
|
|
|
|
coord.i = CORDIC_ANGLE_GEN;
|
|
coord.q = 0;
|
|
angle = 0;
|
|
|
|
theta = CORDIC_FIXED(theta);
|
|
signtheta = (theta < 0) ? -1 : 1;
|
|
theta = ((theta + CORDIC_FIXED(180) * signtheta) % CORDIC_FIXED(360)) -
|
|
CORDIC_FIXED(180) * signtheta;
|
|
|
|
if (CORDIC_FLOAT(theta) > 90) {
|
|
theta -= CORDIC_FIXED(180);
|
|
signx = -1;
|
|
} else if (CORDIC_FLOAT(theta) < -90) {
|
|
theta += CORDIC_FIXED(180);
|
|
signx = -1;
|
|
}
|
|
|
|
for (iter = 0; iter < CORDIC_NUM_ITER; iter++) {
|
|
if (theta > angle) {
|
|
valtmp = coord.i - (coord.q >> iter);
|
|
coord.q += (coord.i >> iter);
|
|
angle += arctan_table[iter];
|
|
} else {
|
|
valtmp = coord.i + (coord.q >> iter);
|
|
coord.q -= (coord.i >> iter);
|
|
angle -= arctan_table[iter];
|
|
}
|
|
coord.i = valtmp;
|
|
}
|
|
|
|
coord.i *= signx;
|
|
coord.q *= signx;
|
|
return coord;
|
|
}
|
|
EXPORT_SYMBOL(cordic_calc_iq);
|
|
|
|
MODULE_DESCRIPTION("CORDIC algorithm");
|
|
MODULE_AUTHOR("Broadcom Corporation");
|
|
MODULE_LICENSE("Dual BSD/GPL");
|