1/*
2 * Copyright (c) 2003-2010, Mark Borgerding. All rights reserved.
3 * This file is part of KISS FFT - https://github.com/mborgerding/kissfft
4 *
5 * SPDX-License-Identifier: BSD-3-Clause
6 * See COPYING file for more information.
7 */
8
9/* kiss_fft.h
10 defines kiss_fft_scalar as either short or a float type
11 and defines
12 typedef struct { kiss_fft_scalar r; kiss_fft_scalar i; }kiss_fft_cpx; */
13
14#ifndef _kiss_fft_guts_h
15#define _kiss_fft_guts_h
16
17#include "kiss_fft.h"
18#include "kiss_fft_log.h"
19#include <limits.h>
20
21#define MAXFACTORS 32
22/* e.g. an fft of length 128 has 4 factors
23 as far as kissfft is concerned
24 4*4*4*2
25 */
26
27struct kiss_fft_state{
28 int nfft;
29 int inverse;
30 int factors[2*MAXFACTORS];
31 kiss_fft_cpx twiddles[1];
32};
33
34/*
35 Explanation of macros dealing with complex math:
36
37 C_MUL(m,a,b) : m = a*b
38 C_FIXDIV( c , div ) : if a fixed point impl., c /= div. noop otherwise
39 C_SUB( res, a,b) : res = a - b
40 C_SUBFROM( res , a) : res -= a
41 C_ADDTO( res , a) : res += a
42 * */
43#ifdef FIXED_POINT
44#include <stdint.h>
45#if (FIXED_POINT==32)
46# define FRACBITS 31
47# define SAMPPROD int64_t
48#define SAMP_MAX INT32_MAX
49#define SAMP_MIN INT32_MIN
50#else
51# define FRACBITS 15
52# define SAMPPROD int32_t
53#define SAMP_MAX INT16_MAX
54#define SAMP_MIN INT16_MIN
55#endif
56
57#if defined(CHECK_OVERFLOW)
58# define CHECK_OVERFLOW_OP(a,op,b) \
59 if ( (SAMPPROD)(a) op (SAMPPROD)(b) > SAMP_MAX || (SAMPPROD)(a) op (SAMPPROD)(b) < SAMP_MIN ) { \
60 KISS_FFT_WARNING("overflow (%d " #op" %d) = %ld", (a),(b),(SAMPPROD)(a) op (SAMPPROD)(b)); }
61#endif
62
63
64# define smul(a,b) ( (SAMPPROD)(a)*(b) )
65# define sround( x ) (kiss_fft_scalar)( ( (x) + (1<<(FRACBITS-1)) ) >> FRACBITS )
66
67# define S_MUL(a,b) sround( smul(a,b) )
68
69# define C_MUL(m,a,b) \
70 do{ (m).r = sround( smul((a).r,(b).r) - smul((a).i,(b).i) ); \
71 (m).i = sround( smul((a).r,(b).i) + smul((a).i,(b).r) ); }while(0)
72
73# define DIVSCALAR(x,k) \
74 (x) = sround( smul( x, SAMP_MAX/k ) )
75
76# define C_FIXDIV(c,div) \
77 do { DIVSCALAR( (c).r , div); \
78 DIVSCALAR( (c).i , div); }while (0)
79
80# define C_MULBYSCALAR( c, s ) \
81 do{ (c).r = sround( smul( (c).r , s ) ) ;\
82 (c).i = sround( smul( (c).i , s ) ) ; }while(0)
83
84#else /* not FIXED_POINT*/
85
86# define S_MUL(a,b) ( (a)*(b) )
87#define C_MUL(m,a,b) \
88 do{ (m).r = (a).r*(b).r - (a).i*(b).i;\
89 (m).i = (a).r*(b).i + (a).i*(b).r; }while(0)
90# define C_FIXDIV(c,div) /* NOOP */
91# define C_MULBYSCALAR( c, s ) \
92 do{ (c).r *= (s);\
93 (c).i *= (s); }while(0)
94#endif
95
96#ifndef CHECK_OVERFLOW_OP
97# define CHECK_OVERFLOW_OP(a,op,b) /* noop */
98#endif
99
100#define C_ADD( res, a,b)\
101 do { \
102 CHECK_OVERFLOW_OP((a).r,+,(b).r)\
103 CHECK_OVERFLOW_OP((a).i,+,(b).i)\
104 (res).r=(a).r+(b).r; (res).i=(a).i+(b).i; \
105 }while(0)
106#define C_SUB( res, a,b)\
107 do { \
108 CHECK_OVERFLOW_OP((a).r,-,(b).r)\
109 CHECK_OVERFLOW_OP((a).i,-,(b).i)\
110 (res).r=(a).r-(b).r; (res).i=(a).i-(b).i; \
111 }while(0)
112#define C_ADDTO( res , a)\
113 do { \
114 CHECK_OVERFLOW_OP((res).r,+,(a).r)\
115 CHECK_OVERFLOW_OP((res).i,+,(a).i)\
116 (res).r += (a).r; (res).i += (a).i;\
117 }while(0)
118
119#define C_SUBFROM( res , a)\
120 do {\
121 CHECK_OVERFLOW_OP((res).r,-,(a).r)\
122 CHECK_OVERFLOW_OP((res).i,-,(a).i)\
123 (res).r -= (a).r; (res).i -= (a).i; \
124 }while(0)
125
126
127#ifdef FIXED_POINT
128# define KISS_FFT_COS(phase) floor(.5+SAMP_MAX * cos (phase))
129# define KISS_FFT_SIN(phase) floor(.5+SAMP_MAX * sin (phase))
130# define HALF_OF(x) ((x)>>1)
131#elif defined(USE_SIMD)
132# define KISS_FFT_COS(phase) _mm_set1_ps( cos(phase) )
133# define KISS_FFT_SIN(phase) _mm_set1_ps( sin(phase) )
134# define HALF_OF(x) ((x)*_mm_set1_ps(.5))
135#else
136# define KISS_FFT_COS(phase) (kiss_fft_scalar) cos(phase)
137# define KISS_FFT_SIN(phase) (kiss_fft_scalar) sin(phase)
138# define HALF_OF(x) ((x)*((kiss_fft_scalar).5))
139#endif
140
141#define kf_cexp(x,phase) \
142 do{ \
143 (x)->r = KISS_FFT_COS(phase);\
144 (x)->i = KISS_FFT_SIN(phase);\
145 }while(0)
146
147
148/* a debugging function */
149#define pcpx(c)\
150 KISS_FFT_DEBUG("%g + %gi\n",(double)((c)->r),(double)((c)->i))
151
152
153#ifdef KISS_FFT_USE_ALLOCA
154// define this to allow use of alloca instead of malloc for temporary buffers
155// Temporary buffers are used in two case:
156// 1. FFT sizes that have "bad" factors. i.e. not 2,3 and 5
157// 2. "in-place" FFTs. Notice the quotes, since kissfft does not really do an in-place transform.
158#include <alloca.h>
159#define KISS_FFT_TMP_ALLOC(nbytes) alloca(nbytes)
160#define KISS_FFT_TMP_FREE(ptr)
161#else
162#define KISS_FFT_TMP_ALLOC(nbytes) KISS_FFT_MALLOC(nbytes)
163#define KISS_FFT_TMP_FREE(ptr) KISS_FFT_FREE(ptr)
164#endif
165
166#endif /* _kiss_fft_guts_h */
167
168