#!/usr/bin/octave -qf
% SPDX-FileCopyrightText: 2023 Brian Woods
% SPDX-License-Identifier: GPL-2.0-or-later
% simple octave executable script to generate input files for filter testing
signals = {"impulse", "sine", "cosine", "square"};
signal = NaN;
freq = NaN;
width = NaN;
signednesses = {"unsigned", "signed"};
signedness = NaN;
samples = NaN;
function print_help(signals)
printf("%s <signal> <freq> <width> <signedess> <samples> <filename>\n", ...
program_name());
printf("where:\n");
printf("\tsignal: the signal type:");
for i = 1:length(signals)
switch(i)
case 1
printf(" %s", signals{i})
otherwise
printf(", %s", signals{i})
endswitch
endfor
printf("\n");
printf("\tfreq: freqency in sample length\n");
printf("\twidth: bit width of the output\n");
printf("\tsignedness: it is either: signed, unsigned\n");
printf("\tsamples: how many samples to generate\n");
printf("\tfilename: output filename\n");
endfunction
% input parsing
arg_list = argv ();
if (nargin != 6)
printf("Too few or too many arguements given.\n");
print_help(signals)
quit;
endif
for i = 1:length(signals)
if strcmp(arg_list{1},signals{i})
signal = i;
break
endif
endfor
if isnan(signal)
printf("can't parse <signal>.\n");
print_help(signals)
exit;
endif
freq = abs(real(str2double(arg_list{2})));
if isnan(freq)
printf("Can't parse <freq>.\n");
print_help(signals)
exit;
endif
width = abs(floor(real(str2double(arg_list{3}))));
if isnan(width)
printf("Can't parse <width>.\n");
print_help(signals)
exit;
endif
for i = 1:length(signednesses)
if strcmp(arg_list{4},signednesses{i})
signedness = i;
break
endif
endfor
if isnan(signedness)
printf("can't parse <signedness>.\n");
print_help(signals)
exit;
endif
samples = abs(floor(real(str2double(arg_list{5}))));
if isnan(width)
printf("Can't parse <width>.\n");
print_help(signals)
exit;
endif
filename = arg_list{6};
fid = fopen (filename, "w");
% end input parsing
% calc ranges
if signedness == 1
range_max = 2**width - 1;
range_min = 0;
else
range_max = 2**(width-1) -1;
%makes things easier not to use the extra negative number
range_min = -range_max;
endif
% actual singal generation
switch (signal)
case 1 % impulse
for i = 0:samples-1
switch (i)
case 0
fprintf(fid, "%d\n", range_max);
otherwise
fprintf(fid, "%d\n", 0);
endswitch;
endfor
case {2, 3} % sine and cosine
if (signedness == 1) % unsigned
sine_amp = range_max/2
sine_off = sine_amp
else % signed
sine_amp = range_max
sine_off = 0
endif
if (signal == 2)
sine_phase = 0;
else % cosine needs a phase offset
sine_phase = pi/2
endif
sine_freq = (2*pi)/freq
for i = 0:samples-1
fprintf(fid, "%d\n",
floor(sine_amp*sin(sine_freq*i+sine_phase)
+ sine_off +.5));
endfor
case 4 % square
freq_half = freq/2;
for i = 0:samples-1
period = rem(i, freq);
if (floor(period/freq_half) == 0) %first half
fprintf(fid, "%d\n", range_max);
else
fprintf(fid, "%d\n", range_min);
endif
endfor
otherwise
printf("can't determine how to generate the signal, exiting\n");
exit;
endswitch
fclose (fid);
