DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (fddffdeab170)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145
/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* ====================================================================
 * Copyright (c) 2005 Carnegie Mellon University.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * This work was supported in part by funding from the Defense Advanced 
 * Research Projects Agency and the National Science Foundation of the 
 * United States of America, and the CMU Sphinx Speech Consortium.
 *
 * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND 
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY
 * NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ==================================================================== */

/* Fixed-point arithmetic macros.
 *
 * Author: David Huggins-Daines <dhuggins@cs.cmu.edu>
 */

#ifndef _FIXPOINT_H_
#define _FIXPOINT_H_

#include <limits.h>

/* Win32/WinCE DLL gunk */
#include <sphinxbase/sphinxbase_export.h>
#include <sphinxbase/prim_type.h>

#ifdef __cplusplus
extern "C" {
#endif
#if 0
/* Fool Emacs. */
}
#endif

#ifndef DEFAULT_RADIX
#define DEFAULT_RADIX 12
#endif

/** Fixed-point computation type. */
typedef int32 fixed32;

/** Convert floating point to fixed point. */
#define FLOAT2FIX_ANY(x,radix) \
	(((x)<0.0) ? \
	((fixed32)((x)*(float32)(1<<(radix)) - 0.5)) \
	: ((fixed32)((x)*(float32)(1<<(radix)) + 0.5)))
#define FLOAT2FIX(x) FLOAT2FIX_ANY(x,DEFAULT_RADIX)
/** Convert fixed point to floating point. */
#define FIX2FLOAT_ANY(x,radix) ((float32)(x)/(1<<(radix)))
#define FIX2FLOAT(x) FIX2FLOAT_ANY(x,DEFAULT_RADIX)

/**
 * Multiply two fixed point numbers with an arbitrary radix point.
 *
 * A veritable multiplicity of implementations exist, starting with
 * the fastest ones...
 */

#if defined(__arm__) && !defined(__thumb__)
/* 
 * This works on most modern ARMs but *only* in ARM mode (for obvious
 * reasons), so don't use it in Thumb mode (but why are you building
 * signal processing code in Thumb mode?!)
 */
#define FIXMUL(a,b) FIXMUL_ANY(a,b,DEFAULT_RADIX)
#define FIXMUL_ANY(a,b,r) ({				\
      int cl, ch, _a = a, _b = b;			\
      __asm__ ("smull %0, %1, %2, %3\n"			\
	   "mov %0, %0, lsr %4\n"			\
	   "orr %0, %0, %1, lsl %5\n"			\
	   : "=&r" (cl), "=&r" (ch)			\
	   : "r" (_a), "r" (_b), "i" (r), "i" (32-(r)));\
      cl; })

#elif defined(_MSC_VER) || (defined(HAVE_LONG_LONG) && SIZEOF_LONG_LONG == 8) 
/* Standard systems*/
#define FIXMUL(a,b) FIXMUL_ANY(a,b,DEFAULT_RADIX)
#define FIXMUL_ANY(a,b,radix) ((fixed32)(((int64)(a)*(b))>>(radix)))

#else
/* Most general case where 'long long' doesn't exist or is slow. */
#define FIXMUL(a,b) FIXMUL_ANY(a,b,DEFAULT_RADIX)
#define FIXMUL_ANY(a,b,radix) ({ \
	int32 _ah, _bh; \
	uint32 _al, _bl, _t, c; \
	_ah = ((int32)(a)) >> 16; \
	_bh = ((int32)(b)) >> 16; \
	_al = ((uint32)(a)) & 0xffff; \
	_bl = ((uint32)(b)) & 0xffff; \
	_t = _ah * _bl + _al * _bh; \
	c = (fixed32)(((_al * _bl) >> (radix)) \
		      + ((_ah * _bh) << (32 - (radix))) \
		      + ((radix) > 16 ? (_t >> (radix - 16)) : (_t << (16 - radix)))); \
	c;})
#endif

/* Various fixed-point logarithmic functions that we need. */
/** Minimum value representable in log format. */
#define MIN_FIXLOG -2829416  /* log(1e-300) * (1<<DEFAULT_RADIX) */
#define MIN_FIXLOG2 -4081985 /* log2(1e-300) * (1<<DEFAULT_RADIX) */
/** Fixed-point representation of log(2) */
#define FIXLN_2		((fixed32)(0.693147180559945 * (1<<DEFAULT_RADIX)))
/** Take natural logarithm of a fixedpoint number. */
#define FIXLN(x) (fixlog(x) - (FIXLN_2 * DEFAULT_RADIX))

/**
 * Take natural logarithm of an integer, yielding a fixedpoint number
 * with DEFAULT_RADIX as radix point.
 */
int32 fixlog(uint32 x);
/**
 * Take base-2 logarithm of an integer, yielding a fixedpoint number
 * with DEFAULT_RADIX as radix point.
 */
int32 fixlog2(uint32 x);

#ifdef __cplusplus
}
#endif


#endif /* _FIXPOINT_H_ */