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