Take 2 at 'Consolidate all fixed point math routines in one library' (FS#10400) by Jeffrey Goode

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21664 a1c6a512-1295-4272-9138-f99709370657

5 files changed, 55 insertions, 121 deletions

diff --git a/apps/codecs/adx.c b/apps/codecs/adx.c
index cc36f6a..0e50054 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 "lib/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)
 {
@@ -238,7 +121,7 @@ next_track:
         int64_t c;
         int64_t d;
         
-        fsincos((unsigned long)phasemultiple,&z);
+        fp_sincos((unsigned long)phasemultiple,&z);
 
         a = (M_SQRT2*big28)-(z*big28/LONG_MAX);
 
@@ -247,7 +130,7 @@ next_track:
          * which is sufficient here, but this is the only reason why I don't
          * use 32 fractional bits everywhere.
          */
-        d = fsqrt((a+b)*(a-b)/big28,28);
+        d = fp_sqrt((a+b)*(a-b)/big28,28);
         c = (a-d)*big28/b;
 
         coef1 = (c*8192) >> 28;
diff --git a/apps/codecs/lib/SOURCES b/apps/codecs/lib/SOURCES
index cbb8e60..0141af2 100644
--- a/apps/codecs/lib/SOURCES
+++ b/apps/codecs/lib/SOURCES
@@ -1,6 +1,6 @@
 #if CONFIG_CODEC == SWCODEC /* software codec platforms */
 codeclib.c
-
+fixedpoint.c
 
 mdct2.c
 #ifdef CPU_ARM
diff --git a/apps/codecs/lib/fixedpoint.c b/apps/codecs/lib/fixedpoint.c
new file mode 100644
index 0000000..352e246
--- /dev/null
+++ b/apps/codecs/lib/fixedpoint.c
@@ -0,0 +1 @@
+#include "../../fixedpoint.c"
diff --git a/apps/codecs/lib/fixedpoint.h b/apps/codecs/lib/fixedpoint.h
new file mode 100644
index 0000000..e6ed520
--- /dev/null
+++ b/apps/codecs/lib/fixedpoint.h
@@ -0,0 +1,49 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id: fixedpoint.h -1   $
+ *
+ * Copyright (C) 2006 Jens Arnold
+ *
+ * Fixed point library for plugins
+ *
+ * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+ /** CODECS - FIXED POINT MATH ROUTINES - USAGE
+ *
+ *  - x and y arguments are fixed point integers
+ *  - fracbits is the number of fractional bits in the argument(s)
+ *  - functions return long fixed point integers with the specified number
+ *    of fractional bits unless otherwise specified
+ *
+ *  Calculate sin and cos of an angle:
+ *      fp_sincos(phase, *cos)
+ *          where phase is a 32 bit unsigned integer with 0 representing 0
+ *          and 0xFFFFFFFF representing 2*pi, and *cos is the address to
+ *          a long signed integer.  Value returned is a long signed integer
+ *          from LONG_MIN to LONG_MAX, representing -1 to 1 respectively.
+ *          That is, value is a fixed point integer with 31 fractional bits.
+ *
+ *  Take square root of a fixed point number:
+ *      fp_sqrt(x, fracbits)
+ *
+ */
+#ifndef _FIXEDPOINT_H_CODECS
+#define _FIXEDPOINT_H_CODECS
+
+long fp_sincos(unsigned long phase, long *cos);
+long fp_sqrt(long a, unsigned int fracbits);
+
+#endif
diff --git a/apps/codecs/spc.c b/apps/codecs/spc.c
index 6ceb704..3a06a22 100644
--- a/apps/codecs/spc.c
+++ b/apps/codecs/spc.c
@@ -26,6 +26,7 @@
 /* DSP Based on Brad Martin's OpenSPC DSP emulator */
 /* tag reading from sexyspc by John Brawn (John_Brawn@yahoo.com) and others */
 #include "codeclib.h"
+#include "../fracmul.h"
 #include "libspc/spc_codec.h"
 #include "libspc/spc_profiler.h"