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radix 5 a little optimized

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Mark Borgerding 2003-11-03 03:48:34 +00:00
parent 3c0c0431e2
commit 0403fb3e4a
1 changed files with 34 additions and 31 deletions
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65
kiss_fft.c
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@ -223,13 +223,9 @@ void bfly5(
kiss_fft_cpx scratch[20];
kiss_fft_cpx * twiddles = st->twiddles;
kiss_fft_cpx *tw1,*tw2,*tw3,*tw4;
kiss_fft_cpx y1,y2,y3,y4;
kiss_fft_cpx y1,y2;
y1 = twiddles[fstride*m];
y2 = twiddles[fstride*2*m];
y3.r = y2.r;
y3.i = -y2.i;
y4.r = y1.r;
y4.i = -y1.i;
Fout0=Fout;
Fout1=Fout0+m;
@ -240,49 +236,56 @@ void bfly5(
tw1=tw2=tw3=tw4 = st->twiddles;
for ( u=0; u<m; ++u ) {
C_FIXDIV( *Fout0,5); C_FIXDIV( *Fout1,5); C_FIXDIV( *Fout2,5); C_FIXDIV( *Fout3,5); C_FIXDIV( *Fout4,5);
scratch[0] = *Fout0;
C_MUL(scratch[1] ,*Fout1, *tw1);
C_MUL(scratch[2] ,*Fout2, *tw2);
C_MUL(scratch[3] ,*Fout3, *tw3);
C_MUL(scratch[4] ,*Fout4, *tw4);
Fout0->r += scratch[1].r + scratch[2].r + scratch[3].r + scratch[4].r;
Fout0->i += scratch[1].i + scratch[2].i + scratch[3].i + scratch[4].i;
scratch[5].r = scratch[1].r*y1.r + scratch[2].r*y2.r + scratch[3].r*y2.r + scratch[4].r*y1.r;
scratch[6].r = scratch[1].i*y1.i + scratch[2].i*y2.i - scratch[3].i*y2.i - scratch[4].i*y1.i;
C_MUL( scratch[5] , scratch[1] , y1 );
C_MUL( scratch[6] , scratch[2] , y2 );
C_MUL( scratch[7] , scratch[3] , y3 );
C_MUL( scratch[8] , scratch[4] , y4 );
Fout1->r = scratch[0].r + scratch[5].r + scratch[6].r + scratch[7].r + scratch[8].r;
Fout1->i = scratch[0].i + scratch[5].i + scratch[6].i + scratch[7].i + scratch[8].i;
scratch[5].i = scratch[1].r*y1.i + scratch[2].r*y2.i - scratch[3].r*y2.i - scratch[4].r*y1.i;
scratch[6].i = scratch[1].i*y1.r + scratch[2].i*y2.r + scratch[3].i*y2.r + scratch[4].i*y1.r;
C_MUL( scratch[5] , scratch[1] , y2 );
C_MUL( scratch[6] , scratch[2] , y4 );
C_MUL( scratch[7] , scratch[3] , y1 );
C_MUL( scratch[8] , scratch[4] , y3 );
Fout2->r = scratch[0].r + scratch[5].r + scratch[6].r + scratch[7].r + scratch[8].r;
Fout2->i = scratch[0].i + scratch[5].i + scratch[6].i + scratch[7].i + scratch[8].i;
Fout1->r = scratch[0].r + scratch[5].r - scratch[6].r;
Fout1->i = scratch[0].i + scratch[5].i + scratch[6].i;
C_MUL( scratch[5] , scratch[1] , y3 );
C_MUL( scratch[6] , scratch[2] , y1 );
C_MUL( scratch[7] , scratch[3] , y4 );
C_MUL( scratch[8] , scratch[4] , y2 );
Fout3->r = scratch[0].r + scratch[5].r + scratch[6].r + scratch[7].r + scratch[8].r;
Fout3->i = scratch[0].i + scratch[5].i + scratch[6].i + scratch[7].i + scratch[8].i;
Fout4->r = scratch[0].r + scratch[5].r + scratch[6].r;
Fout4->i = scratch[0].i - scratch[5].i + scratch[6].i;
Fout2->r = scratch[0].r +
scratch[1].r*y2.r - scratch[1].i*y2.i +
scratch[2].r*y1.r + scratch[2].i*y1.i +
scratch[3].r*y1.r - scratch[3].i*y1.i +
scratch[4].r*y2.r + scratch[4].i*y2.i;
Fout2->i = scratch[0].i +
scratch[1].r*y2.i + scratch[1].i*y2.r -
scratch[2].r*y1.i + scratch[2].i*y1.r +
scratch[3].r*y1.i + scratch[3].i*y1.r -
scratch[4].r*y2.i + scratch[4].i*y2.r;
Fout3->r = scratch[0].r +
scratch[1].r*y2.r + scratch[1].i*y2.i +
scratch[2].r*y1.r - scratch[2].i*y1.i +
scratch[3].r*y1.r + scratch[3].i*y1.i +
scratch[4].r*y2.r - scratch[4].i*y2.i;
Fout3->i = scratch[0].i -
scratch[1].r*y2.i + scratch[1].i*y2.r +
scratch[2].r*y1.i + scratch[2].i*y1.r -
scratch[3].r*y1.i + scratch[3].i*y1.r +
scratch[4].r*y2.i + scratch[4].i*y2.r;
C_MUL( scratch[5] , scratch[1] , y4 );
C_MUL( scratch[6] , scratch[2] , y3 );
C_MUL( scratch[7] , scratch[3] , y2 );
C_MUL( scratch[8] , scratch[4] , y1 );
Fout4->r = scratch[0].r + scratch[5].r + scratch[6].r + scratch[7].r + scratch[8].r;
Fout4->i = scratch[0].i + scratch[5].i + scratch[6].i + scratch[7].i + scratch[8].i;
++Fout0;++Fout1;++Fout2;++Fout3;++Fout4;
tw1+=fstride;
tw2+=2*fstride;
tw3+=3*fstride;
tw4+=4*fstride;
}
}