void benchmark_quantize_adc(struct rusage * _start,
struct rusage * _finish,
unsigned long int * _num_iterations)
{
unsigned long int i;
unsigned int q = 0;
unsigned int num_bits=8;
float x=-0.1f;
// start trials
getrusage(RUSAGE_SELF, _start);
for (i=0; i<(*_num_iterations); i++) {
q ^= quantize_adc(x,num_bits);
q ^= quantize_adc(x,num_bits);
q ^= quantize_adc(x,num_bits);
q ^= quantize_adc(x,num_bits);
}
getrusage(RUSAGE_SELF, _finish);
*_num_iterations *= 4;
}
int main(int argc, char*argv[]) {
// options
unsigned int num_bits=4;
char filename[256] = "";
int dopt;
while ((dopt = getopt(argc,argv,"uhb:o:")) != EOF) {
switch (dopt) {
case 'u':
case 'h': usage(); return 0;
case 'b': num_bits = atoi(optarg); break;
case 'o': strncpy(filename,optarg,255); break;
default:
exit(1);
}
}
// append null character to end of filename
filename[255] = '\0';
// derived values
unsigned int n = 1<<(num_bits+4);
// allocate memory for arrays
float x[n];
float y[n];
unsigned int i;
for (i=0; i<n; i++) {
// generate input signal
x[i] = (2.0f * (float)(i) / (float)(n)) - 1.0f;
// quantize: analog to digital converter
unsigned int q = quantize_adc(x[i],num_bits);
// quantize: digital to analog converter
y[i] = quantize_dac(q,num_bits);
}
//
// export output file
//
FILE * fid = fopen(filename,"w");
if (!fid) {
fprintf(stderr,"error: %s, could not open '%s' for writing\n", argv[0], filename);
exit(1);
}
fprintf(fid,"# %s: auto-generated file\n\n", filename);
fprintf(fid,"reset\n");
fprintf(fid,"set terminal postscript eps enhanced color solid rounded\n");
fprintf(fid,"set xrange [-1:1];\n");
fprintf(fid,"set yrange [-1:1];\n");
fprintf(fid,"set size ratio 1.0\n");
fprintf(fid,"set xlabel 'DAC input'\n");
fprintf(fid,"set ylabel 'DAC output'\n");
fprintf(fid,"set key top right nobox\n");
fprintf(fid,"set grid xtics ytics\n");
fprintf(fid,"set grid linetype 1 linecolor rgb '%s' lw 1\n", LIQUID_DOC_COLOR_GRID);
fprintf(fid,"plot '-' using 1:2 with lines linetype 1 linewidth 1 linecolor rgb '%s' notitle,\\\n", LIQUID_DOC_COLOR_GRAY);
fprintf(fid," '-' using 1:2 with steps linetype 1 linewidth 3 linecolor rgb '%s' notitle\n", LIQUID_DOC_COLOR_RED);
//
fprintf(fid," -1.0 -1.0\n");
fprintf(fid," 1.0 1.0\n");
fprintf(fid,"e\n");
for (i=0; i<n; i++)
fprintf(fid," %16.8e %16.8e;\n", x[i], y[i]);
fprintf(fid,"e\n");
// close output file
fclose(fid);
return 0;
}
