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146 lines
4.9 KiB
C
146 lines
4.9 KiB
C
/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */
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/* ====================================================================
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* Copyright (c) 2005 Carnegie Mellon University. All rights
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* reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* This work was supported in part by funding from the Defense Advanced
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* Research Projects Agency and the National Science Foundation of the
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* United States of America, and the CMU Sphinx Speech Consortium.
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*
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* THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND
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* ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY
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* NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* ==================================================================== */
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/* Fixed-point arithmetic macros.
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*
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* Author: David Huggins-Daines <dhuggins@cs.cmu.edu>
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*/
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#ifndef _FIXPOINT_H_
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#define _FIXPOINT_H_
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#include <limits.h>
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/* Win32/WinCE DLL gunk */
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#include <sphinxbase/sphinxbase_export.h>
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#include <sphinxbase/prim_type.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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#if 0
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/* Fool Emacs. */
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}
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#endif
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#ifndef DEFAULT_RADIX
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#define DEFAULT_RADIX 12
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#endif
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/** Fixed-point computation type. */
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typedef int32 fixed32;
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/** Convert floating point to fixed point. */
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#define FLOAT2FIX_ANY(x,radix) \
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(((x)<0.0) ? \
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((fixed32)((x)*(float32)(1<<(radix)) - 0.5)) \
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: ((fixed32)((x)*(float32)(1<<(radix)) + 0.5)))
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#define FLOAT2FIX(x) FLOAT2FIX_ANY(x,DEFAULT_RADIX)
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/** Convert fixed point to floating point. */
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#define FIX2FLOAT_ANY(x,radix) ((float32)(x)/(1<<(radix)))
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#define FIX2FLOAT(x) FIX2FLOAT_ANY(x,DEFAULT_RADIX)
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/**
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* Multiply two fixed point numbers with an arbitrary radix point.
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*
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* A veritable multiplicity of implementations exist, starting with
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* the fastest ones...
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*/
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#if defined(__arm__) && !defined(__thumb__)
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/*
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* This works on most modern ARMs but *only* in ARM mode (for obvious
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* reasons), so don't use it in Thumb mode (but why are you building
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* signal processing code in Thumb mode?!)
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*/
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#define FIXMUL(a,b) FIXMUL_ANY(a,b,DEFAULT_RADIX)
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#define FIXMUL_ANY(a,b,r) ({ \
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int cl, ch, _a = a, _b = b; \
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__asm__ ("smull %0, %1, %2, %3\n" \
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"mov %0, %0, lsr %4\n" \
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"orr %0, %0, %1, lsl %5\n" \
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: "=&r" (cl), "=&r" (ch) \
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: "r" (_a), "r" (_b), "i" (r), "i" (32-(r)));\
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cl; })
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#elif defined(_MSC_VER) || (defined(HAVE_LONG_LONG) && SIZEOF_LONG_LONG == 8)
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/* Standard systems*/
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#define FIXMUL(a,b) FIXMUL_ANY(a,b,DEFAULT_RADIX)
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#define FIXMUL_ANY(a,b,radix) ((fixed32)(((int64)(a)*(b))>>(radix)))
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#else
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/* Most general case where 'long long' doesn't exist or is slow. */
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#define FIXMUL(a,b) FIXMUL_ANY(a,b,DEFAULT_RADIX)
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#define FIXMUL_ANY(a,b,radix) ({ \
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int32 _ah, _bh; \
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uint32 _al, _bl, _t, c; \
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_ah = ((int32)(a)) >> 16; \
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_bh = ((int32)(b)) >> 16; \
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_al = ((uint32)(a)) & 0xffff; \
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_bl = ((uint32)(b)) & 0xffff; \
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_t = _ah * _bl + _al * _bh; \
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c = (fixed32)(((_al * _bl) >> (radix)) \
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+ ((_ah * _bh) << (32 - (radix))) \
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+ ((radix) > 16 ? (_t >> (radix - 16)) : (_t << (16 - radix)))); \
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c;})
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#endif
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/* Various fixed-point logarithmic functions that we need. */
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/** Minimum value representable in log format. */
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#define MIN_FIXLOG -2829416 /* log(1e-300) * (1<<DEFAULT_RADIX) */
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#define MIN_FIXLOG2 -4081985 /* log2(1e-300) * (1<<DEFAULT_RADIX) */
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/** Fixed-point representation of log(2) */
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#define FIXLN_2 ((fixed32)(0.693147180559945 * (1<<DEFAULT_RADIX)))
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/** Take natural logarithm of a fixedpoint number. */
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#define FIXLN(x) (fixlog(x) - (FIXLN_2 * DEFAULT_RADIX))
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/**
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* Take natural logarithm of an integer, yielding a fixedpoint number
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* with DEFAULT_RADIX as radix point.
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*/
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int32 fixlog(uint32 x);
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/**
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* Take base-2 logarithm of an integer, yielding a fixedpoint number
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* with DEFAULT_RADIX as radix point.
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*/
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int32 fixlog2(uint32 x);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _FIXPOINT_H_ */
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