1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_cfft_radix8_f16.c
4 * Description: Radix-8 Decimation in Frequency CFFT & CIFFT Floating point processing function
5 *
6 * $Date: 23 April 2021
7 * $Revision: V1.9.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
13 *
14 * SPDX-License-Identifier: Apache-2.0
15 *
16 * Licensed under the Apache License, Version 2.0 (the License); you may
17 * not use this file except in compliance with the License.
18 * You may obtain a copy of the License at
19 *
20 * www.apache.org/licenses/LICENSE-2.0
21 *
22 * Unless required by applicable law or agreed to in writing, software
23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25 * See the License for the specific language governing permissions and
26 * limitations under the License.
27 */
28
29 #include "dsp/transform_functions_f16.h"
30
31 #if defined(ARM_FLOAT16_SUPPORTED)
32
33
34 /* ----------------------------------------------------------------------
35 * Internal helper function used by the FFTs
36 * -------------------------------------------------------------------- */
37
38 /**
39 brief Core function for the floating-point CFFT butterfly process.
40 param[in,out] pSrc points to the in-place buffer of floating-point data type.
41 param[in] fftLen length of the FFT.
42 param[in] pCoef points to the twiddle coefficient buffer.
43 param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
44 return none
45 */
46
arm_radix8_butterfly_f16(float16_t * pSrc,uint16_t fftLen,const float16_t * pCoef,uint16_t twidCoefModifier)47 void arm_radix8_butterfly_f16(
48 float16_t * pSrc,
49 uint16_t fftLen,
50 const float16_t * pCoef,
51 uint16_t twidCoefModifier)
52 {
53 uint32_t ia1, ia2, ia3, ia4, ia5, ia6, ia7;
54 uint32_t i1, i2, i3, i4, i5, i6, i7, i8;
55 uint32_t id;
56 uint32_t n1, n2, j;
57
58 float16_t r1, r2, r3, r4, r5, r6, r7, r8;
59 float16_t t1, t2;
60 float16_t s1, s2, s3, s4, s5, s6, s7, s8;
61 float16_t p1, p2, p3, p4;
62 float16_t co2, co3, co4, co5, co6, co7, co8;
63 float16_t si2, si3, si4, si5, si6, si7, si8;
64 const float16_t C81 = 0.70710678118f;
65
66 n2 = fftLen;
67
68 do
69 {
70 n1 = n2;
71 n2 = n2 >> 3;
72 i1 = 0;
73
74 do
75 {
76 i2 = i1 + n2;
77 i3 = i2 + n2;
78 i4 = i3 + n2;
79 i5 = i4 + n2;
80 i6 = i5 + n2;
81 i7 = i6 + n2;
82 i8 = i7 + n2;
83 r1 = pSrc[2 * i1] + pSrc[2 * i5];
84 r5 = pSrc[2 * i1] - pSrc[2 * i5];
85 r2 = pSrc[2 * i2] + pSrc[2 * i6];
86 r6 = pSrc[2 * i2] - pSrc[2 * i6];
87 r3 = pSrc[2 * i3] + pSrc[2 * i7];
88 r7 = pSrc[2 * i3] - pSrc[2 * i7];
89 r4 = pSrc[2 * i4] + pSrc[2 * i8];
90 r8 = pSrc[2 * i4] - pSrc[2 * i8];
91 t1 = r1 - r3;
92 r1 = r1 + r3;
93 r3 = r2 - r4;
94 r2 = r2 + r4;
95 pSrc[2 * i1] = r1 + r2;
96 pSrc[2 * i5] = r1 - r2;
97 r1 = pSrc[2 * i1 + 1] + pSrc[2 * i5 + 1];
98 s5 = pSrc[2 * i1 + 1] - pSrc[2 * i5 + 1];
99 r2 = pSrc[2 * i2 + 1] + pSrc[2 * i6 + 1];
100 s6 = pSrc[2 * i2 + 1] - pSrc[2 * i6 + 1];
101 s3 = pSrc[2 * i3 + 1] + pSrc[2 * i7 + 1];
102 s7 = pSrc[2 * i3 + 1] - pSrc[2 * i7 + 1];
103 r4 = pSrc[2 * i4 + 1] + pSrc[2 * i8 + 1];
104 s8 = pSrc[2 * i4 + 1] - pSrc[2 * i8 + 1];
105 t2 = r1 - s3;
106 r1 = r1 + s3;
107 s3 = r2 - r4;
108 r2 = r2 + r4;
109 pSrc[2 * i1 + 1] = r1 + r2;
110 pSrc[2 * i5 + 1] = r1 - r2;
111 pSrc[2 * i3] = t1 + s3;
112 pSrc[2 * i7] = t1 - s3;
113 pSrc[2 * i3 + 1] = t2 - r3;
114 pSrc[2 * i7 + 1] = t2 + r3;
115 r1 = (r6 - r8) * C81;
116 r6 = (r6 + r8) * C81;
117 r2 = (s6 - s8) * C81;
118 s6 = (s6 + s8) * C81;
119 t1 = r5 - r1;
120 r5 = r5 + r1;
121 r8 = r7 - r6;
122 r7 = r7 + r6;
123 t2 = s5 - r2;
124 s5 = s5 + r2;
125 s8 = s7 - s6;
126 s7 = s7 + s6;
127 pSrc[2 * i2] = r5 + s7;
128 pSrc[2 * i8] = r5 - s7;
129 pSrc[2 * i6] = t1 + s8;
130 pSrc[2 * i4] = t1 - s8;
131 pSrc[2 * i2 + 1] = s5 - r7;
132 pSrc[2 * i8 + 1] = s5 + r7;
133 pSrc[2 * i6 + 1] = t2 - r8;
134 pSrc[2 * i4 + 1] = t2 + r8;
135
136 i1 += n1;
137 } while (i1 < fftLen);
138
139 if (n2 < 8)
140 break;
141
142 ia1 = 0;
143 j = 1;
144
145 do
146 {
147 /* index calculation for the coefficients */
148 id = ia1 + twidCoefModifier;
149 ia1 = id;
150 ia2 = ia1 + id;
151 ia3 = ia2 + id;
152 ia4 = ia3 + id;
153 ia5 = ia4 + id;
154 ia6 = ia5 + id;
155 ia7 = ia6 + id;
156
157 co2 = pCoef[2 * ia1];
158 co3 = pCoef[2 * ia2];
159 co4 = pCoef[2 * ia3];
160 co5 = pCoef[2 * ia4];
161 co6 = pCoef[2 * ia5];
162 co7 = pCoef[2 * ia6];
163 co8 = pCoef[2 * ia7];
164 si2 = pCoef[2 * ia1 + 1];
165 si3 = pCoef[2 * ia2 + 1];
166 si4 = pCoef[2 * ia3 + 1];
167 si5 = pCoef[2 * ia4 + 1];
168 si6 = pCoef[2 * ia5 + 1];
169 si7 = pCoef[2 * ia6 + 1];
170 si8 = pCoef[2 * ia7 + 1];
171
172 i1 = j;
173
174 do
175 {
176 /* index calculation for the input */
177 i2 = i1 + n2;
178 i3 = i2 + n2;
179 i4 = i3 + n2;
180 i5 = i4 + n2;
181 i6 = i5 + n2;
182 i7 = i6 + n2;
183 i8 = i7 + n2;
184 r1 = pSrc[2 * i1] + pSrc[2 * i5];
185 r5 = pSrc[2 * i1] - pSrc[2 * i5];
186 r2 = pSrc[2 * i2] + pSrc[2 * i6];
187 r6 = pSrc[2 * i2] - pSrc[2 * i6];
188 r3 = pSrc[2 * i3] + pSrc[2 * i7];
189 r7 = pSrc[2 * i3] - pSrc[2 * i7];
190 r4 = pSrc[2 * i4] + pSrc[2 * i8];
191 r8 = pSrc[2 * i4] - pSrc[2 * i8];
192 t1 = r1 - r3;
193 r1 = r1 + r3;
194 r3 = r2 - r4;
195 r2 = r2 + r4;
196 pSrc[2 * i1] = r1 + r2;
197 r2 = r1 - r2;
198 s1 = pSrc[2 * i1 + 1] + pSrc[2 * i5 + 1];
199 s5 = pSrc[2 * i1 + 1] - pSrc[2 * i5 + 1];
200 s2 = pSrc[2 * i2 + 1] + pSrc[2 * i6 + 1];
201 s6 = pSrc[2 * i2 + 1] - pSrc[2 * i6 + 1];
202 s3 = pSrc[2 * i3 + 1] + pSrc[2 * i7 + 1];
203 s7 = pSrc[2 * i3 + 1] - pSrc[2 * i7 + 1];
204 s4 = pSrc[2 * i4 + 1] + pSrc[2 * i8 + 1];
205 s8 = pSrc[2 * i4 + 1] - pSrc[2 * i8 + 1];
206 t2 = s1 - s3;
207 s1 = s1 + s3;
208 s3 = s2 - s4;
209 s2 = s2 + s4;
210 r1 = t1 + s3;
211 t1 = t1 - s3;
212 pSrc[2 * i1 + 1] = s1 + s2;
213 s2 = s1 - s2;
214 s1 = t2 - r3;
215 t2 = t2 + r3;
216 p1 = co5 * r2;
217 p2 = si5 * s2;
218 p3 = co5 * s2;
219 p4 = si5 * r2;
220 pSrc[2 * i5] = p1 + p2;
221 pSrc[2 * i5 + 1] = p3 - p4;
222 p1 = co3 * r1;
223 p2 = si3 * s1;
224 p3 = co3 * s1;
225 p4 = si3 * r1;
226 pSrc[2 * i3] = p1 + p2;
227 pSrc[2 * i3 + 1] = p3 - p4;
228 p1 = co7 * t1;
229 p2 = si7 * t2;
230 p3 = co7 * t2;
231 p4 = si7 * t1;
232 pSrc[2 * i7] = p1 + p2;
233 pSrc[2 * i7 + 1] = p3 - p4;
234 r1 = (r6 - r8) * C81;
235 r6 = (r6 + r8) * C81;
236 s1 = (s6 - s8) * C81;
237 s6 = (s6 + s8) * C81;
238 t1 = r5 - r1;
239 r5 = r5 + r1;
240 r8 = r7 - r6;
241 r7 = r7 + r6;
242 t2 = s5 - s1;
243 s5 = s5 + s1;
244 s8 = s7 - s6;
245 s7 = s7 + s6;
246 r1 = r5 + s7;
247 r5 = r5 - s7;
248 r6 = t1 + s8;
249 t1 = t1 - s8;
250 s1 = s5 - r7;
251 s5 = s5 + r7;
252 s6 = t2 - r8;
253 t2 = t2 + r8;
254 p1 = co2 * r1;
255 p2 = si2 * s1;
256 p3 = co2 * s1;
257 p4 = si2 * r1;
258 pSrc[2 * i2] = p1 + p2;
259 pSrc[2 * i2 + 1] = p3 - p4;
260 p1 = co8 * r5;
261 p2 = si8 * s5;
262 p3 = co8 * s5;
263 p4 = si8 * r5;
264 pSrc[2 * i8] = p1 + p2;
265 pSrc[2 * i8 + 1] = p3 - p4;
266 p1 = co6 * r6;
267 p2 = si6 * s6;
268 p3 = co6 * s6;
269 p4 = si6 * r6;
270 pSrc[2 * i6] = p1 + p2;
271 pSrc[2 * i6 + 1] = p3 - p4;
272 p1 = co4 * t1;
273 p2 = si4 * t2;
274 p3 = co4 * t2;
275 p4 = si4 * t1;
276 pSrc[2 * i4] = p1 + p2;
277 pSrc[2 * i4 + 1] = p3 - p4;
278
279 i1 += n1;
280 } while (i1 < fftLen);
281
282 j++;
283 } while (j < n2);
284
285 twidCoefModifier <<= 3;
286 } while (n2 > 7);
287 }
288
289 #endif /* #if defined(ARM_FLOAT16_SUPPORTED) */
