?? wib_fft_f.c
字號:
fft_tbl fft_tbl_inst
)
{
//complex16 data_reorder[256];
unsigned short i,j,k,p;
signed short exp_statge[3] = {0,0,0},exponent = 0;
unsigned char bit_width; //width of fft compute
unsigned short N; //point of fft
unsigned char COEF_W ;
unsigned short BOUND1;
unsigned short BOUND2,BOUND3;
unsigned char log2n;
complex16 *p_dat;
unsigned short base,index,index_wp,base_index_wp;
complex16 x1,x2,x3,x4;
unsigned short temp1;
complex16 *p_w1p,*p_w2p,*p_w3p;
unsigned short *p_reorder_idx;
unsigned char degree;
FILE *fp_outdbg;
// signed short test;
p_w1p = fft_tbl_inst.p_w1p;
p_w2p = fft_tbl_inst.p_w2p;
p_w3p = fft_tbl_inst.p_w3p;
p_reorder_idx = fft_tbl_inst.p_reorder_idx;
p_dat = p_dat_out;
N = fft_tbl_inst.N;
bit_width = fft_tbl_inst.bit_width;
BOUND1 = (unsigned short)(1 << (bit_width-1));
BOUND2 = (unsigned short)(1 << (bit_width));
BOUND3 = (unsigned short)(1 << (bit_width+1));
COEF_W = bit_width-1;
degree = fft_tbl_inst.degree;
log2n = fft_tbl_inst.log2n;
//data reorder
for (i = 0; i < N; i++)
{
p_dat[i].r = (p_dat_in + *(p_reorder_idx+i)) -> r;
if (mode) {
p_dat[i].i = (signed short)(-((p_dat_in + *(p_reorder_idx+i)) -> i));
} else {
p_dat[i].i = (p_dat_in + *(p_reorder_idx+i)) -> i;
}
}
for (i = 0; i < N; i++) {
if (((p_dat[i].r) >= BOUND1) || ((p_dat[i].r) < -BOUND1)){
exp_statge[0] = 1;
}
if (((p_dat[i].i) >= BOUND1) || ((p_dat[i].i) < -BOUND1)){
exp_statge[0] = 1;
}
}
if(exp_statge[0]) {
for (i = 0; i < N; i++) {
p_dat[i].r = p_dat[i].r >> 1;
p_dat[i].i = p_dat[i].i >> 1;
}
}
//printf("N:%d\n",N >> 6);
exp_statge[0] = 0;
k = 0;
base_index_wp = 0;
for (i = 0; i < degree; i++) {
base_index_wp = (unsigned short)(base_index_wp + k);
index_wp = base_index_wp;
//t2 = N;
temp1 = (unsigned short)(N >> (unsigned short)((i + 1) * 2));
//temp1 = (N / pow(4,i+1));
// printf("tem:%d\n%d\n",temp1,i);
for (j = 0; j < temp1; j++) { //for k=1:N/(4^degree)
base = (unsigned short)(j * POW4I);
k = 0;
do {
index = (unsigned short)(base + k);
//if result is too large then shorten bits
if (exp_statge[2]) {
x1.r = (signed short)(p_dat[index].r >> 3);
x1.i = (signed short)(p_dat[index].i >> 3);
x2.r = (signed short)(p_dat[index+POW4I_1].r >> 3);
x2.i = (signed short)(p_dat[index+POW4I_1].i >> 3);
x3.r = (signed short)(p_dat[index+2*POW4I_1].r >> 3);
x3.i = (signed short)(p_dat[index+2*POW4I_1].i >> 3);
x4.r = (signed short)(p_dat[index+3*POW4I_1].r >> 3);
x4.i = (signed short)(p_dat[index+3*POW4I_1].i >> 3);
}
else if (exp_statge[1]) {
x1.r = (signed short)(p_dat[index].r >> 2);
x1.i = (signed short)(p_dat[index].i >> 2);
x2.r = (signed short)(p_dat[index+POW4I_1].r >> 2);
x2.i = (signed short)(p_dat[index+POW4I_1].i >> 2);
x3.r = (signed short)(p_dat[index+2*POW4I_1].r >> 2);
x3.i = (signed short)(p_dat[index+2*POW4I_1].i >> 2);
x4.r = (signed short)(p_dat[index+3*POW4I_1].r >> 2);
x4.i = (signed short)(p_dat[index+3*POW4I_1].i >> 2);
} else if (exp_statge[0]) {
x1.r = (signed short)(p_dat[index].r >> 1);
x1.i = (signed short)(p_dat[index].i >> 1);
x2.r = (signed short)(p_dat[index+POW4I_1].r >> 1);
x2.i = (signed short)(p_dat[index+POW4I_1].i >> 1);
x3.r = (signed short)(p_dat[index+2*POW4I_1].r >> 1);
x3.i = (signed short)(p_dat[index+2*POW4I_1].i >> 1);
x4.r = (signed short)(p_dat[index+3*POW4I_1].r >> 1);
x4.i = (signed short)(p_dat[index+3*POW4I_1].i >> 1);
} else {
x1.r = p_dat[index].r;
x1.i = p_dat[index].i;
x2.r = p_dat[index+POW4I_1].r;
x2.i = p_dat[index+POW4I_1].i;
x3.r = p_dat[index+2*POW4I_1].r;
x3.i = p_dat[index+2*POW4I_1].i;
x4.r = p_dat[index+3*POW4I_1].r;
x4.i = p_dat[index+3*POW4I_1].i;
}
index_wp = (unsigned short)(base_index_wp + k);
// base4 butterfly
dft4p(x1,x2,x3,x4,p_w1p[index_wp],p_w2p[index_wp],p_w3p[index_wp],
COEF_W,&p_dat[index],&p_dat[index+POW4I_1],
&p_dat[index+2*POW4I_1],&p_dat[index+3*POW4I_1]);
}while(++k < POW4I_1);
}
if (exp_statge[2]) {
exponent = (signed short)(exponent + 3);
} else if (exp_statge[1]) {
exponent = (signed short)(exponent + 2);
} else if(exp_statge[0]) {
exponent = (signed short)(exponent + 1);
}
exp_statge[0] = 0;
exp_statge[1] = 0;
exp_statge[2] = 0;
for (p = 0; p < N; p++) {
if (((p_dat[p].r) >= BOUND3) || ((p_dat[p].r) < -BOUND3)){
exp_statge[2] = 1;
} else if (((p_dat[p].r) >= BOUND2) || ((p_dat[p].r) < -BOUND2)){
exp_statge[1] = 1;
} else if (((p_dat[p].r) >= BOUND1) || ((p_dat[p].r) < -BOUND1)){
exp_statge[0] = 1;
}
if (((p_dat[p].i) >= BOUND3) || ((p_dat[p].i) < -BOUND3)){
exp_statge[2] = 1;
} else if (((p_dat[p].i) >= BOUND2) || ((p_dat[p].i) < -BOUND2)){
exp_statge[1] = 1;
} else if (((p_dat[p].i) >= BOUND1) || ((p_dat[p].i) < -BOUND1)) {
exp_statge[0] = 1;
}
}
}
// }
// xx = clock()-xx;
// printf("FFT time is %d",xx);
exp_statge[0] = 0;
exp_statge[1] = 0;
exp_statge[2] = 0;
for (p = 0; p < N; p++) {
if (((p_dat[p].r) >= BOUND3) || ((p_dat[p].r) < -BOUND3)){
exp_statge[2] = 1;
} else if (((p_dat[p].r) >= BOUND2) || ((p_dat[p].r) < -BOUND2)){
exp_statge[1] = 1;
} else if (((p_dat[p].r) >= BOUND1) || ((p_dat[p].r) < -BOUND1)){
exp_statge[0] = 1;
}
if (((p_dat[p].i) >= BOUND3) || ((p_dat[p].i) < -BOUND3)){
exp_statge[2] = 1;
} else if (((p_dat[p].i) >= BOUND2) || ((p_dat[p].i) < -BOUND2)){
exp_statge[1] = 1;
} else if (((p_dat[p].i) >= BOUND1) || ((p_dat[p].i) < -BOUND1)) {
exp_statge[0] = 1;
}
}
if (exp_statge[2]) {
for (i = 0; i < N; i++) {
(p_dat+i)->r = (signed short)(((p_dat+i)->r) >> 3);
(p_dat+i)->i = (signed short)(((p_dat+i)->i) >> 3);
}
} else if (exp_statge[1]) {
for (i = 0; i < N; i++) {
(p_dat+i)->r = (signed short)(((p_dat+i)->r) >> 2);
(p_dat+i)->i = (signed short)(((p_dat+i)->i) >> 2);
}
} else if (exp_statge[0]) {
for (i = 0; i < N; i++) {
(p_dat+i)->r = (signed short)(((p_dat+i)->r) >> 1);
(p_dat+i)->i = (signed short)(((p_dat+i)->i) >> 1);
}
}
if (exp_statge[2]) {
exponent = (signed short)(exponent + 3);
} else if (exp_statge[1]) {
exponent = (signed short)(exponent + 2);
} else if(exp_statge[0]) {
exponent = (signed short)(exponent + 1);
}
if (mode) {
for (i = 0; i < N; i++) {
if(((p_dat+i)->i) == -BOUND1) {
(p_dat+i)->i = BOUND1-1;
} else {
(p_dat+i)->i = (signed short)(-((p_dat+i)->i));
}
}
}
if (mode) {
exponent = (signed short)(exponent-log2n);
}
if(exponent==-8) {
exponent=-8;
}
#ifdef DEBUG_OUT_FFT_EXPONENT
if (mode) {
fp_outdbg = fopen("fft_exponent.txt","at"); //append, txt
fprintf(fp_outdbg,"%d\n",exponent);
fclose(fp_outdbg);
}
#endif
return exponent;
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