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| 1 @// |
| 2 @// Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. |
| 3 @// |
| 4 @// Use of this source code is governed by a BSD-style license |
| 5 @// that can be found in the LICENSE file in the root of the source |
| 6 @// tree. An additional intellectual property rights grant can be found |
| 7 @// in the file PATENTS. All contributing project authors may |
| 8 @// be found in the AUTHORS file in the root of the source tree. |
| 9 @// |
| 10 @// This is a modification of |
| 11 @// armSP_FFTInv_CCSToR_S32_preTwiddleRadix2_unsafe_s.s to support float |
| 12 @// instead of SC32. |
| 13 @// |
| 14 |
| 15 @// |
| 16 @// Description: |
| 17 @// Compute the "preTwiddleRadix2" stage prior to the call to the complexFFT |
| 18 @// It does a Z(k) = Feven(k) + jW^(-k) FOdd(k); k=0,1,2,...N/2-1 computation |
| 19 @// |
| 20 @// |
| 21 |
| 22 |
| 23 @// Include standard headers |
| 24 |
| 25 #include "dl/api/armCOMM_s.h" |
| 26 #include "dl/api/omxtypes_s.h" |
| 27 |
| 28 |
| 29 @// Import symbols required from other files |
| 30 @// (For example tables) |
| 31 |
| 32 |
| 33 @// Set debugging level |
| 34 @//DEBUG_ON SETL {TRUE} |
| 35 |
| 36 |
| 37 |
| 38 @// Guarding implementation by the processor name |
| 39 |
| 40 |
| 41 |
| 42 @// Guarding implementation by the processor name |
| 43 |
| 44 |
| 45 |
| 46 @//Input Registers |
| 47 |
| 48 #define pSrc r0 |
| 49 #define pDst r1 |
| 50 #define pFFTSpec r2 |
| 51 #define scale r3 |
| 52 |
| 53 |
| 54 @// Output registers |
| 55 #define result r0 |
| 56 |
| 57 @//Local Scratch Registers |
| 58 |
| 59 #define argTwiddle r1 |
| 60 #define argDst r2 |
| 61 #define argScale r4 |
| 62 #define tmpOrder r4 |
| 63 #define pTwiddle r4 |
| 64 #define pOut r5 |
| 65 #define subFFTSize r7 |
| 66 #define subFFTNum r6 |
| 67 #define N r6 |
| 68 #define order r14 |
| 69 #define diff r9 |
| 70 @// Total num of radix stages required to complete the FFT |
| 71 #define count r8 |
| 72 #define x0r r4 |
| 73 #define x0i r5 |
| 74 #define diffMinusOne r2 |
| 75 #define round r3 |
| 76 |
| 77 #define pOut1 r2 |
| 78 #define size r7 |
| 79 #define step r8 |
| 80 #define step1 r9 |
| 81 #define twStep r10 |
| 82 #define pTwiddleTmp r11 |
| 83 #define argTwiddle1 r12 |
| 84 #define zero r14 |
| 85 |
| 86 @// Neon registers |
| 87 |
| 88 #define dX0 D0.F32 |
| 89 #define dShift D1.F32 |
| 90 #define dX1 D1.F32 |
| 91 #define dY0 D2.F32 |
| 92 #define dY1 D3.F32 |
| 93 #define dX0r D0.F32 |
| 94 #define dX0i D1.F32 |
| 95 #define dX1r D2.F32 |
| 96 #define dX1i D3.F32 |
| 97 #define dW0r D4.F32 |
| 98 #define dW0i D5.F32 |
| 99 #define dW1r D6.F32 |
| 100 #define dW1i D7.F32 |
| 101 #define dT0 D8.F32 |
| 102 #define dT1 D9.F32 |
| 103 #define dT2 D10.F32 |
| 104 #define dT3 D11.F32 |
| 105 #define qT0 D12.F32 |
| 106 #define qT1 D14.F32 |
| 107 #define qT2 D16.F32 |
| 108 #define qT3 D18.F32 |
| 109 #define dY0r D4.F32 |
| 110 #define dY0i D5.F32 |
| 111 #define dY1r D6.F32 |
| 112 #define dY1i D7.F32 |
| 113 |
| 114 #define dY2 D4.F32 |
| 115 #define dY3 D5.F32 |
| 116 #define dW0 D6.F32 |
| 117 #define dW1 D7.F32 |
| 118 #define dW0Tmp D10.F32 |
| 119 #define dW1Neg D11.F32 |
| 120 |
| 121 #define half D13.F32 |
| 122 |
| 123 @ Structure offsets for the FFTSpec |
| 124 .set ARMsFFTSpec_N, 0 |
| 125 .set ARMsFFTSpec_pBitRev, 4 |
| 126 .set ARMsFFTSpec_pTwiddle, 8 |
| 127 .set ARMsFFTSpec_pBuf, 12 |
| 128 |
| 129 .MACRO FFTSTAGE scaled, inverse, name |
| 130 |
| 131 @// Read the size from structure and take log |
| 132 LDR N, [pFFTSpec, #ARMsFFTSpec_N] |
| 133 |
| 134 @// Read other structure parameters |
| 135 LDR pTwiddle, [pFFTSpec, #ARMsFFTSpec_pTwiddle] |
| 136 LDR pOut, [pFFTSpec, #ARMsFFTSpec_pBuf] |
| 137 |
| 138 VMOV half, 0.5 |
| 139 |
| 140 |
| 141 MOV size,N,ASR #1 @// preserve the contents of N |
| 142 MOV step,N,LSL #2 @// step = N/2 * 8 bytes |
| 143 |
| 144 |
| 145 @// Z(k) = 1/2 {[F(k) + F'(N/2-k)] +j*W^(-k) [F(k) - F'(N/2-k)]} |
| 146 @// Note: W^(k) is stored as negated value and also need to |
| 147 @// conjugate the values from the table |
| 148 |
| 149 @// Z(0) : no need of twiddle multiply |
| 150 @// Z(0) = 1/2 { [F(0) + F'(N/2)] +j [F(0) - F'(N/2)] } |
| 151 |
| 152 VLD1 dX0,[pSrc],step |
| 153 ADD pOut1,pOut,step @// pOut1 = pOut+ N/2*8 bytes |
| 154 |
| 155 VLD1 dX1,[pSrc]! |
| 156 @// twStep = 3N/8 * 8 bytes pointing to W^1 |
| 157 SUB twStep,step,size,LSL #1 |
| 158 |
| 159 MOV step1,size,LSL #2 @// step1 = N/4 * 8 = N/2*4 bytes |
| 160 SUB step1,step1,#8 @// (N/4-1)*8 bytes |
| 161 |
| 162 VADD dY0,dX0,dX1 @// [b+d | a+c] |
| 163 VSUB dY1,dX0,dX1 @// [b-d | a-c] |
| 164 VMUL dY0, dY0, half[0] |
| 165 VMUL dY1, dY1, half[0] |
| 166 |
| 167 @// dY0= [a-c | a+c] ;dY1= [b-d | b+d] |
| 168 VZIP dY0,dY1 |
| 169 |
| 170 VSUB dX0,dY0,dY1 |
| 171 SUBS size,size,#2 |
| 172 VADD dX1,dY0,dY1 |
| 173 |
| 174 SUB pSrc,pSrc,step |
| 175 |
| 176 VST1 dX0[0],[pOut1]! |
| 177 ADD pTwiddleTmp,pTwiddle,#8 @// W^2 |
| 178 VST1 dX1[1],[pOut1]! |
| 179 ADD argTwiddle1,pTwiddle,twStep @// W^1 |
| 180 |
| 181 |
| 182 BLT decrementScale\name |
| 183 BEQ lastElement\name |
| 184 |
| 185 |
| 186 @// Z(k) = 1/2[F(k) + F'(N/2-k)] +j*W^(-k) [F(k) - F'(N/2-k)] |
| 187 @// Note: W^k is stored as negative values in the table and also |
| 188 @// need to conjugate the values from the table. |
| 189 @// |
| 190 @// Process 4 elements at a time. E.g: Z(1),Z(2) and Z(N/2-2),Z(N/2-1) |
| 191 @// since both of them require F(1),F(2) and F(N/2-2),F(N/2-1) |
| 192 |
| 193 |
| 194 SUB step,step,#24 |
| 195 evenOddButterflyLoop\name : |
| 196 |
| 197 |
| 198 VLD1 dW0r,[argTwiddle1],step1 |
| 199 VLD1 dW1r,[argTwiddle1]! |
| 200 |
| 201 VLD2 {dX0r,dX0i},[pSrc],step |
| 202 SUB argTwiddle1,argTwiddle1,step1 |
| 203 VLD2 {dX1r,dX1i},[pSrc]! |
| 204 |
| 205 SUB step1,step1,#8 @// (N/4-2)*8 bytes |
| 206 VLD1 dW0i,[pTwiddleTmp],step1 |
| 207 VLD1 dW1i,[pTwiddleTmp]! |
| 208 SUB pSrc,pSrc,step |
| 209 |
| 210 SUB pTwiddleTmp,pTwiddleTmp,step1 |
| 211 VREV64 dX1r,dX1r |
| 212 VREV64 dX1i,dX1i |
| 213 SUBS size,size,#4 |
| 214 |
| 215 |
| 216 VSUB dT2,dX0r,dX1r @// a-c |
| 217 VADD dT3,dX0i,dX1i @// b+d |
| 218 VADD dT0,dX0r,dX1r @// a+c |
| 219 VSUB dT1,dX0i,dX1i @// b-d |
| 220 SUB step1,step1,#8 |
| 221 |
| 222 VMUL dT2, dT2, half[0] |
| 223 VMUL dT3, dT3, half[0] |
| 224 |
| 225 VMUL dT0, dT0, half[0] |
| 226 VMUL dT1, dT1, half[0] |
| 227 |
| 228 VZIP dW1r,dW1i |
| 229 VZIP dW0r,dW0i |
| 230 |
| 231 |
| 232 VMUL dX1r,dW1r,dT2 |
| 233 VMUL dX1i,dW1r,dT3 |
| 234 VMUL dX0r,dW0r,dT2 |
| 235 VMUL dX0i,dW0r,dT3 |
| 236 |
| 237 VMLS dX1r,dW1i,dT3 |
| 238 VMLA dX1i,dW1i,dT2 |
| 239 |
| 240 VMLA dX0r,dW0i,dT3 |
| 241 VMLS dX0i,dW0i,dT2 |
| 242 |
| 243 |
| 244 VADD dY1r,dT0,dX1i @// F(N/2 -1) |
| 245 VSUB dY1i,dX1r,dT1 |
| 246 |
| 247 VREV64 dY1r,dY1r |
| 248 VREV64 dY1i,dY1i |
| 249 |
| 250 |
| 251 VADD dY0r,dT0,dX0i @// F(1) |
| 252 VSUB dY0i,dT1,dX0r |
| 253 |
| 254 |
| 255 VST2 {dY0r,dY0i},[pOut1],step |
| 256 VST2 {dY1r,dY1i},[pOut1]! |
| 257 SUB pOut1,pOut1,step |
| 258 SUB step,step,#32 @// (N/2-4)*8 bytes |
| 259 |
| 260 |
| 261 BGT evenOddButterflyLoop\name |
| 262 |
| 263 |
| 264 @// set both the ptrs to the last element |
| 265 SUB pSrc,pSrc,#8 |
| 266 SUB pOut1,pOut1,#8 |
| 267 |
| 268 @// Last element can be expanded as follows |
| 269 @// 1/2[Z(k) + Z'(k)] - j w^-k [Z(k) - Z'(k)] (since W^k is stored as |
| 270 @// -ve) |
| 271 @// 1/2[(a+jb) + (a-jb)] - j w^-k [(a+jb) - (a-jb)] |
| 272 @// 1/2[2a+j0] - j (c-jd) [0+j2b] |
| 273 @// (a+bc, -bd) |
| 274 @// Since (c,d) = (0,1) for the last element, result is just (a,-b) |
| 275 |
| 276 lastElement\name : |
| 277 VLD1 dX0r,[pSrc] |
| 278 |
| 279 VST1 dX0r[0],[pOut1]! |
| 280 VNEG dX0r,dX0r |
| 281 VST1 dX0r[1],[pOut1] |
| 282 |
| 283 |
| 284 |
| 285 decrementScale\name : |
| 286 |
| 287 .endm |
| 288 |
| 289 M_START armSP_FFTInv_CCSToR_F32_preTwiddleRadix2_unsafe,r4 |
| 290 |
| 291 FFTSTAGE "FALSE","TRUE",Inv |
| 292 M_END |
| 293 |
| 294 .end |
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