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authorMaurus Cuelenaere <mcuelenaere@gmail.com>2009-07-04 12:26:45 +0000
committerMaurus Cuelenaere <mcuelenaere@gmail.com>2009-07-04 12:26:45 +0000
commit4710a3280025b0ba8ffb6e8183578a5df48257fa (patch)
tree3dd82b90ab668c18109d0885cd3114449efaddf1 /apps/codecs/adx.c
parent69c73e8bd6c8c6ac79c6538cb0ad4686b9d1d920 (diff)
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Consolidate all fixed point math routines in one library (FS#10400) by Jeffrey Goode
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21633 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/codecs/adx.c')
-rw-r--r--apps/codecs/adx.c119
1 files changed, 1 insertions, 118 deletions
diff --git a/apps/codecs/adx.c b/apps/codecs/adx.c
index cc36f6a908..e23b3d4f80 100644
--- a/apps/codecs/adx.c
+++ b/apps/codecs/adx.c
@@ -21,6 +21,7 @@
#include "codeclib.h"
#include "inttypes.h"
#include "math.h"
+#include "fixedpoint.h"
CODEC_HEADER
@@ -41,124 +42,6 @@ const long cutoff = 500;
static int16_t samples[WAV_CHUNK_SIZE] IBSS_ATTR;
-/* fixed point stuff from apps/plugins/lib/fixedpoint.c */
-
-/* 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;
- }
- }
-
- if (cos)
- *cos = x;
-
- return y;
-}
-
-/**
- * Fixed point square root via Newton-Raphson.
- * @param a square root argument.
- * @param fracbits specifies number of fractional bits in argument.
- * @return Square root of argument in same fixed point format as input.
- */
-static long fsqrt(long a, unsigned int fracbits)
-{
- long b = a/2 + (1 << fracbits); /* initial approximation */
- unsigned n;
- const unsigned iterations = 8; /* bumped up from 4 as it wasn't
- nearly enough for 28 fractional bits */
-
- for (n = 0; n < iterations; ++n)
- b = (b + (long)(((long long)(a) << fracbits)/b))/2;
-
- return b;
-}
-
/* this is the codec entry point */
enum codec_status codec_main(void)
{