Ktam3874/pitx software guide – Kontron KTAM3874-pITX User Manual
Page 94
KTD-S0057-I
Page 90 Linux® Programming Examples (DebianTM)
KTAM3874/pITX Software Guide
/* verify and prepare the contents of areas */
for (chn = 0; chn < channels; chn++)
{
if ((areas[chn].first % 8) != 0)
{
printf ("areas[%i].first == %i, aborting...\n", chn, areas[chn].first);
exit
(EXIT_FAILURE);
}
samples[chn] = (((unsigned char *) areas[chn].addr) + (areas[chn].first / 8));
if ((areas[chn].step % 16) != 0)
{
printf ("areas[%i].step == %i, aborting...\n", chn, areas[chn].step);
exit
(EXIT_FAILURE);
}
steps[chn] = areas[chn].step / 8;
samples[chn] += offset * steps[chn];
}
/* fill the channel areas */
while (count-- > 0)
{
union
{
float
f;
int
i;
}
fval;
int res, i;
if
(is_float)
{
fval.f = sin (phase) * maxval;
res = fval.i;
}
else
res = sin (phase) * maxval;
if
(to_unsigned)
res ^= 1U << (format_bits - 1);
for (chn = 0; chn < channels; chn++)
{
/* generate data in native endian format */
if
(big_endian)
{
for (i = 0; i < bps; i++)
*(samples[chn] + phys_bps - 1 - i) = (res >> i * 8) & 0xff;
}
else
{
for (i = 0; i < bps; i++)
*(samples[chn] + i) = (res >> i * 8) & 0xff;
}
samples[chn] += steps[chn];
}