diff options
Diffstat (limited to 'apps/eq.c')
-rw-r--r-- | apps/eq.c | 97 |
1 files changed, 1 insertions, 96 deletions
@@ -21,105 +21,10 @@ #include <inttypes.h> #include "config.h" -#include "dsp.h" +#include "fixedpoint.h" #include "eq.h" #include "replaygain.h" -/* 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 */ -}; - -/** - * 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. - */ -static long fsincos(unsigned long phase, long *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; - } - } - - *cos = x; - - return y; -} - /** * Calculate first order shelving filter. Filter is not directly usable by the * eq_filter() function. |