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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2009 Mohamed Tarek
*
* 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.
*
****************************************************************************/
#include <stdlib.h>
#include <inttypes.h>
/* Macros for converting between various fixed-point representations and floating point. */
#define ONE_16 (1L << 16)
#define fixtof64(x) (float)((float)(x) / (float)(1 << 16)) //does not work on int64_t!
#define ftofix32(x) ((int32_t)((x) * (float)(1 << 16) + ((x) < 0 ? -0.5 : 0.5)))
#define ftofix31(x) ((int32_t)((x) * (float)(1 << 31) + ((x) < 0 ? -0.5 : 0.5)))
#define fix31tof64(x) (float)((float)(x) / (float)(1 << 31))
/* Fixed point math routines for use in atrac3.c */
#if defined(CPU_ARM)
/* Calculates: result = (X*Y)>>16 */
#define fixmul16(X,Y) \
({ \
int32_t lo; \
int32_t hi; \
asm volatile ( \
"smull %[lo], %[hi], %[x], %[y] \n\t" /* multiply */ \
"mov %[lo], %[lo], lsr #16 \n\t" /* lo >>= 16 */ \
"orr %[lo], %[lo], %[hi], lsl #16" /* lo |= (hi << 16) */ \
: [lo]"=&r"(lo), [hi]"=&r"(hi) \
: [x]"r"(X), [y]"r"(Y)); \
lo; \
})
/* Calculates: result = (X*Y)>>31 */
/* Use scratch register r12 */
#define fixmul31(X,Y) \
({ \
int32_t lo; \
int32_t hi; \
asm volatile ( \
"smull %[lo], %[hi], %[x], %[y] \n\t" /* multiply */ \
"mov %[lo], %[lo], lsr #31 \n\t" /* lo >>= 31 */ \
"orr %[lo], %[lo], %[hi], lsl #1" /* lo |= (hi << 1) */ \
: [lo]"=&r"(lo), [hi]"=&r"(hi) \
: [x]"r"(X), [y]"r"(Y)); \
lo; \
})
#elif defined(CPU_COLDFIRE)
/* Calculates: result = (X*Y)>>16 */
#define fixmul16(X,Y) \
({ \
int32_t t, x = (X); \
asm volatile ( \
"mac.l %[x],%[y],%%acc0\n\t" /* multiply */ \
"mulu.l %[y],%[x] \n\t" /* get lower half, avoid emac stall */ \
"movclr.l %%acc0,%[t] \n\t" /* get higher half */ \
"lsr.l #1,%[t] \n\t" /* hi >>= 1 to compensate emac shift */ \
"move.w %[t],%[x] \n\t" /* combine halfwords */\
"swap %[x] \n\t" \
: [t]"=&d"(t), [x] "+d" (x) \
: [y] "d" ((Y))); \
x; \
})
#define fixmul31(X,Y) \
({ \
int32_t t; \
asm volatile ( \
"mac.l %[x], %[y], %%acc0\n\t" /* multiply */ \
"movclr.l %%acc0, %[t]\n\t" /* get higher half as result */ \
: [t] "=d" (t) \
: [x] "r" ((X)), [y] "r" ((Y))); \
t; \
})
#else
static inline int32_t fixmul16(int32_t x, int32_t y)
{
int64_t temp;
temp = x;
temp *= y;
temp >>= 16;
return (int32_t)temp;
}
static inline int32_t fixmul31(int32_t x, int32_t y)
{
int64_t temp;
temp = x;
temp *= y;
temp >>= 31; //16+31-16 = 31 bits
return (int32_t)temp;
}
#endif
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