1 /* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 /* ====================================================================
3 * Copyright (c) 2005 Carnegie Mellon University. All rights
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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11 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
18 * This work was supported in part by funding from the Defense Advanced
19 * Research Projects Agency and the National Science Foundation of the
20 * United States of America, and the CMU Sphinx Speech Consortium.
22 * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND
23 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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34 * ==================================================================== */
36 /* Fixed-point arithmetic macros.
38 * Author: David Huggins-Daines <dhuggins@cs.cmu.edu>
46 /* Win32/WinCE DLL gunk */
47 #include <sphinxbase/sphinxbase_export.h>
48 #include <sphinxbase/prim_type.h>
59 #define DEFAULT_RADIX 12
62 /** Fixed-point computation type. */
63 typedef int32 fixed32;
65 /** Convert floating point to fixed point. */
66 #define FLOAT2FIX_ANY(x,radix) \
68 ((fixed32)((x)*(float32)(1<<(radix)) - 0.5)) \
69 : ((fixed32)((x)*(float32)(1<<(radix)) + 0.5)))
70 #define FLOAT2FIX(x) FLOAT2FIX_ANY(x,DEFAULT_RADIX)
71 /** Convert fixed point to floating point. */
72 #define FIX2FLOAT_ANY(x,radix) ((float32)(x)/(1<<(radix)))
73 #define FIX2FLOAT(x) FIX2FLOAT_ANY(x,DEFAULT_RADIX)
76 * Multiply two fixed point numbers with an arbitrary radix point.
78 * A veritable multiplicity of implementations exist, starting with
84 * This works on most modern ARMs but *only* in ARM mode (for obvious
85 * reasons), so don't use it in Thumb mode (but why are you building
86 * signal processing code in Thumb mode?!)
88 #if defined(__arm__) && !defined(__thumb__)
89 #define FIXMUL(a,b) FIXMUL_ANY(a,b,DEFAULT_RADIX)
90 #define FIXMUL_ANY(a,b,r) ({ \
91 int cl, ch, _a = a, _b = b; \
92 __asm__ ("smull %0, %1, %2, %3\n" \
93 "mov %0, %0, lsr %4\n" \
94 "orr %0, %0, %1, lsl %5\n" \
95 : "=&r" (cl), "=&r" (ch) \
96 : "r" (_a), "r" (_b), "i" (r), "i" (32-(r)));\
98 #elif defined(BFIN) && DEFAULT_RADIX == 16
101 /* Use the accumulators for the 16.16 case (probably not as efficient as it could be). */
102 #define FIXMUL(a,b) ({ \
103 int c, _a = a, _b = b; \
104 __asm__("%0.L = %1.l * %2.l (FU);\n\t" \
105 "%0.H = %1.h * %2.h (IS);\n\t" \
107 "A1 += %1.h * %2.l (IS, M);\n\t" \
108 "%0 = (A1 += %2.h * %1.l) (IS, M);\n\t" \
110 : "d" (_a), "d" (_b) \
113 #define FIXMUL_ANY(a,b,radix) ((fixed32)(((int64)(a)*(b))>>(radix)))
114 #elif defined(_MSC_VER) || (defined(HAVE_LONG_LONG) && SIZEOF_LONG_LONG == 8)
115 #define FIXMUL(a,b) FIXMUL_ANY(a,b,DEFAULT_RADIX)
116 #define FIXMUL_ANY(a,b,radix) ((fixed32)(((int64)(a)*(b))>>(radix)))
117 #else /* Most general case where 'long long' doesn't exist or is slow. */
118 #define FIXMUL(a,b) FIXMUL_ANY(a,b,DEFAULT_RADIX)
119 #define FIXMUL_ANY(a,b,radix) \
120 (fixed32)(((((uint32)(a))&((1<<(radix))-1)) \
121 * (((uint32)(b))&((1<<(radix))-1)) >> (radix)) \
122 + (((((int32)(a))>>(radix)) * (((int32)(b))>>(radix))) << (radix)) \
123 + ((((uint32)(a))&((1<<(radix))-1)) * (((int32)(b))>>(radix))) \
124 + ((((uint32)(b))&((1<<(radix))-1)) * (((int32)(a))>>(radix))))
127 /* Various fixed-point logarithmic functions that we need. */
128 /** Minimum value representable in log format. */
129 #define MIN_FIXLOG -2829416 /* log(1e-300) * (1<<DEFAULT_RADIX) */
130 #define MIN_FIXLOG2 -4081985 /* log2(1e-300) * (1<<DEFAULT_RADIX) */
131 /** Fixed-point representation of log(2) */
132 #define FIXLN_2 ((fixed32)(0.693147180559945 * (1<<DEFAULT_RADIX)))
133 /** Take natural logarithm of a fixedpoint number. */
134 #define FIXLN(x) (fixlog(x) - (FIXLN_2 * DEFAULT_RADIX))
136 * Take natural logarithm of an integer, yielding a fixedpoint number
137 * with DEFAULT_RADIX as radix point.
139 int32 fixlog(uint32 x);
141 * Take base-2 logarithm of an integer, yielding a fixedpoint number
142 * with DEFAULT_RADIX as radix point.
144 int32 fixlog2(uint32 x);
151 #endif /* _FIXPOINT_H_ */