1 | /*
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2 | * FFT/IFFT transforms
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3 | * AltiVec-enabled
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4 | * Copyright (c) 2003 Romain Dolbeau <[email protected]>
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5 | * Based on code Copyright (c) 2002 Fabrice Bellard.
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6 | *
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7 | * This library is free software; you can redistribute it and/or
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8 | * modify it under the terms of the GNU Lesser General Public
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9 | * License as published by the Free Software Foundation; either
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10 | * version 2 of the License, or (at your option) any later version.
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11 | *
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12 | * This library is distributed in the hope that it will be useful,
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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15 | * Lesser General Public License for more details.
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16 | *
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17 | * You should have received a copy of the GNU Lesser General Public
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18 | * License along with this library; if not, write to the Free Software
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19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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20 | */
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21 | #include "../dsputil.h"
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22 |
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23 | #include "gcc_fixes.h"
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24 |
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25 | #include "dsputil_altivec.h"
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26 |
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27 | /*
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28 | those three macros are from libavcodec/fft.c
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29 | and are required for the reference C code
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30 | */
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31 | /* butter fly op */
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32 | #define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
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33 | {\
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34 | FFTSample ax, ay, bx, by;\
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35 | bx=pre1;\
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36 | by=pim1;\
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37 | ax=qre1;\
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38 | ay=qim1;\
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39 | pre = (bx + ax);\
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40 | pim = (by + ay);\
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41 | qre = (bx - ax);\
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42 | qim = (by - ay);\
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43 | }
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44 | #define MUL16(a,b) ((a) * (b))
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45 | #define CMUL(pre, pim, are, aim, bre, bim) \
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46 | {\
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47 | pre = (MUL16(are, bre) - MUL16(aim, bim));\
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48 | pim = (MUL16(are, bim) + MUL16(bre, aim));\
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49 | }
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50 |
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51 |
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52 | /**
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53 | * Do a complex FFT with the parameters defined in ff_fft_init(). The
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54 | * input data must be permuted before with s->revtab table. No
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55 | * 1.0/sqrt(n) normalization is done.
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56 | * AltiVec-enabled
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57 | * This code assumes that the 'z' pointer is 16 bytes-aligned
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58 | * It also assumes all FFTComplex are 8 bytes-aligned pair of float
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59 | * The code is exactly the same as the SSE version, except
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60 | * that successive MUL + ADD/SUB have been merged into
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61 | * fused multiply-add ('vec_madd' in altivec)
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62 | */
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63 | void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z)
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64 | {
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65 | POWERPC_PERF_DECLARE(altivec_fft_num, s->nbits >= 6);
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66 | #ifdef ALTIVEC_USE_REFERENCE_C_CODE
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67 | int ln = s->nbits;
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68 | int j, np, np2;
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69 | int nblocks, nloops;
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70 | register FFTComplex *p, *q;
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71 | FFTComplex *exptab = s->exptab;
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72 | int l;
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73 | FFTSample tmp_re, tmp_im;
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74 |
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75 | POWERPC_PERF_START_COUNT(altivec_fft_num, s->nbits >= 6);
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76 |
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77 | np = 1 << ln;
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78 |
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79 | /* pass 0 */
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80 |
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81 | p=&z[0];
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82 | j=(np >> 1);
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83 | do {
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84 | BF(p[0].re, p[0].im, p[1].re, p[1].im,
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85 | p[0].re, p[0].im, p[1].re, p[1].im);
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86 | p+=2;
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87 | } while (--j != 0);
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88 |
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89 | /* pass 1 */
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90 |
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91 |
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92 | p=&z[0];
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93 | j=np >> 2;
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94 | if (s->inverse) {
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95 | do {
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96 | BF(p[0].re, p[0].im, p[2].re, p[2].im,
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97 | p[0].re, p[0].im, p[2].re, p[2].im);
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98 | BF(p[1].re, p[1].im, p[3].re, p[3].im,
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99 | p[1].re, p[1].im, -p[3].im, p[3].re);
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100 | p+=4;
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101 | } while (--j != 0);
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102 | } else {
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103 | do {
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104 | BF(p[0].re, p[0].im, p[2].re, p[2].im,
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105 | p[0].re, p[0].im, p[2].re, p[2].im);
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106 | BF(p[1].re, p[1].im, p[3].re, p[3].im,
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107 | p[1].re, p[1].im, p[3].im, -p[3].re);
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108 | p+=4;
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109 | } while (--j != 0);
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110 | }
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111 | /* pass 2 .. ln-1 */
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112 |
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113 | nblocks = np >> 3;
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114 | nloops = 1 << 2;
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115 | np2 = np >> 1;
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116 | do {
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117 | p = z;
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118 | q = z + nloops;
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119 | for (j = 0; j < nblocks; ++j) {
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120 | BF(p->re, p->im, q->re, q->im,
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121 | p->re, p->im, q->re, q->im);
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122 |
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123 | p++;
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124 | q++;
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125 | for(l = nblocks; l < np2; l += nblocks) {
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126 | CMUL(tmp_re, tmp_im, exptab[l].re, exptab[l].im, q->re, q->im);
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127 | BF(p->re, p->im, q->re, q->im,
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128 | p->re, p->im, tmp_re, tmp_im);
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129 | p++;
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130 | q++;
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131 | }
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132 |
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133 | p += nloops;
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134 | q += nloops;
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135 | }
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136 | nblocks = nblocks >> 1;
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137 | nloops = nloops << 1;
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138 | } while (nblocks != 0);
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139 |
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140 | POWERPC_PERF_STOP_COUNT(altivec_fft_num, s->nbits >= 6);
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141 |
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142 | #else /* ALTIVEC_USE_REFERENCE_C_CODE */
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143 | #ifdef CONFIG_DARWIN
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144 | register const vector float vczero = (const vector float)(0.);
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145 | #else
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146 | register const vector float vczero = (const vector float){0.,0.,0.,0.};
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147 | #endif
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148 |
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149 | int ln = s->nbits;
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150 | int j, np, np2;
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151 | int nblocks, nloops;
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152 | register FFTComplex *p, *q;
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153 | FFTComplex *cptr, *cptr1;
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154 | int k;
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155 |
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156 | POWERPC_PERF_START_COUNT(altivec_fft_num, s->nbits >= 6);
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157 |
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158 | np = 1 << ln;
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159 |
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160 | {
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161 | vector float *r, a, b, a1, c1, c2;
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162 |
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163 | r = (vector float *)&z[0];
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164 |
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165 | c1 = vcii(p,p,n,n);
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166 |
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167 | if (s->inverse)
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168 | {
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169 | c2 = vcii(p,p,n,p);
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170 | }
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171 | else
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172 | {
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173 | c2 = vcii(p,p,p,n);
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174 | }
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175 |
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176 | j = (np >> 2);
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177 | do {
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178 | a = vec_ld(0, r);
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179 | a1 = vec_ld(sizeof(vector float), r);
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180 |
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181 | b = vec_perm(a,a,vcprmle(1,0,3,2));
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182 | a = vec_madd(a,c1,b);
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183 | /* do the pass 0 butterfly */
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184 |
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185 | b = vec_perm(a1,a1,vcprmle(1,0,3,2));
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186 | b = vec_madd(a1,c1,b);
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187 | /* do the pass 0 butterfly */
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188 |
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189 | /* multiply third by -i */
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190 | b = vec_perm(b,b,vcprmle(2,3,1,0));
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191 |
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192 | /* do the pass 1 butterfly */
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193 | vec_st(vec_madd(b,c2,a), 0, r);
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194 | vec_st(vec_nmsub(b,c2,a), sizeof(vector float), r);
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195 |
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196 | r += 2;
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197 | } while (--j != 0);
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198 | }
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199 | /* pass 2 .. ln-1 */
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200 |
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201 | nblocks = np >> 3;
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202 | nloops = 1 << 2;
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203 | np2 = np >> 1;
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204 |
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205 | cptr1 = s->exptab1;
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206 | do {
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207 | p = z;
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208 | q = z + nloops;
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209 | j = nblocks;
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210 | do {
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211 | cptr = cptr1;
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212 | k = nloops >> 1;
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213 | do {
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214 | vector float a,b,c,t1;
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215 |
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216 | a = vec_ld(0, (float*)p);
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217 | b = vec_ld(0, (float*)q);
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218 |
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219 | /* complex mul */
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220 | c = vec_ld(0, (float*)cptr);
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221 | /* cre*re cim*re */
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222 | t1 = vec_madd(c, vec_perm(b,b,vcprmle(2,2,0,0)),vczero);
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223 | c = vec_ld(sizeof(vector float), (float*)cptr);
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224 | /* -cim*im cre*im */
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225 | b = vec_madd(c, vec_perm(b,b,vcprmle(3,3,1,1)),t1);
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226 |
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227 | /* butterfly */
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228 | vec_st(vec_add(a,b), 0, (float*)p);
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229 | vec_st(vec_sub(a,b), 0, (float*)q);
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230 |
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231 | p += 2;
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232 | q += 2;
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233 | cptr += 4;
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234 | } while (--k);
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235 |
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236 | p += nloops;
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237 | q += nloops;
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238 | } while (--j);
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239 | cptr1 += nloops * 2;
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240 | nblocks = nblocks >> 1;
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241 | nloops = nloops << 1;
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242 | } while (nblocks != 0);
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243 |
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244 | POWERPC_PERF_STOP_COUNT(altivec_fft_num, s->nbits >= 6);
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245 |
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246 | #endif /* ALTIVEC_USE_REFERENCE_C_CODE */
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247 | }
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