rockbox/apps/codecs/lib/fixedpoint.h
Maurus Cuelenaere 4710a32800 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
2009-07-04 12:26:45 +00:00

126 lines
3.9 KiB
C

/***************************************************************************
* __________ __ ___.
* 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.
*
****************************************************************************/
#ifndef _FIXEDPOINT_H
#define _FIXEDPOINT_H
#include <inttypes.h>
/** TAKEN FROM apps/dsp.h */
/* A bunch of fixed point assembler helper macros */
#if defined(CPU_COLDFIRE)
/* These macros use the Coldfire EMAC extension and need the MACSR flags set
* to fractional mode with no rounding.
*/
/* Multiply two S.31 fractional integers and return the sign bit and the
* 31 most significant bits of the result.
*/
#define FRACMUL(x, y) \
({ \
long t; \
asm ("mac.l %[a], %[b], %%acc0\n\t" \
"movclr.l %%acc0, %[t]\n\t" \
: [t] "=r" (t) : [a] "r" (x), [b] "r" (y)); \
t; \
})
/* Multiply two S.31 fractional integers, and return the 32 most significant
* bits after a shift left by the constant z. NOTE: Only works for shifts of
* 1 to 8 on Coldfire!
*/
#define FRACMUL_SHL(x, y, z) \
({ \
long t, t2; \
asm ("mac.l %[a], %[b], %%acc0\n\t" \
"moveq.l %[d], %[t]\n\t" \
"move.l %%accext01, %[t2]\n\t" \
"and.l %[mask], %[t2]\n\t" \
"lsr.l %[t], %[t2]\n\t" \
"movclr.l %%acc0, %[t]\n\t" \
"asl.l %[c], %[t]\n\t" \
"or.l %[t2], %[t]\n\t" \
: [t] "=&d" (t), [t2] "=&d" (t2) \
: [a] "r" (x), [b] "r" (y), [mask] "d" (0xff), \
[c] "i" ((z)), [d] "i" (8 - (z))); \
t; \
})
#elif defined(CPU_ARM)
/* Multiply two S.31 fractional integers and return the sign bit and the
* 31 most significant bits of the result.
*/
#define FRACMUL(x, y) \
({ \
long t, t2; \
asm ("smull %[t], %[t2], %[a], %[b]\n\t" \
"mov %[t2], %[t2], asl #1\n\t" \
"orr %[t], %[t2], %[t], lsr #31\n\t" \
: [t] "=&r" (t), [t2] "=&r" (t2) \
: [a] "r" (x), [b] "r" (y)); \
t; \
})
/* Multiply two S.31 fractional integers, and return the 32 most significant
* bits after a shift left by the constant z.
*/
#define FRACMUL_SHL(x, y, z) \
({ \
long t, t2; \
asm ("smull %[t], %[t2], %[a], %[b]\n\t" \
"mov %[t2], %[t2], asl %[c]\n\t" \
"orr %[t], %[t2], %[t], lsr %[d]\n\t" \
: [t] "=&r" (t), [t2] "=&r" (t2) \
: [a] "r" (x), [b] "r" (y), \
[c] "M" ((z) + 1), [d] "M" (31 - (z))); \
t; \
})
#else
#define FRACMUL(x, y) (long) (((((long long) (x)) * ((long long) (y))) >> 31))
#define FRACMUL_SHL(x, y, z) \
((long)(((((long long) (x)) * ((long long) (y))) >> (31 - (z)))))
#endif
#define DIV64(x, y, z) (long)(((long long)(x) << (z))/(y))
/** TAKEN FROM ORIGINAL fixedpoint.h */
/* fast unsigned multiplication (16x16bit->32bit or 32x32bit->32bit,
* whichever is faster for the architecture) */
#ifdef CPU_ARM
#define FMULU(a, b) ((uint32_t) (((uint32_t) (a)) * ((uint32_t) (b))))
#else /* SH1, coldfire */
#define FMULU(a, b) ((uint32_t) (((uint16_t) (a)) * ((uint16_t) (b))))
#endif
long fsincos(unsigned long phase, long *cos);
long fsqrt(long a, unsigned int fracbits);
long cos_int(int val);
long sin_int(int val);
long flog(int x);
#endif