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Switched to more straightforward version of two-step loop, dealing with my mistaken dealing of when _master_divider&15 == 0 upon entry without adding an extra sanity check. Am also temporarily on non-modulo logic for tone generation, for a profiling test.

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This commit is contained in:
Thomas Harte 2016-10-23 20:32:48 -04:00
parent 583db88299
commit b12f2f2796
2 changed files with 27 additions and 15 deletions
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41
Components/AY38910/AY38910.cpp
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@ -12,7 +12,7 @@ using namespace GI;
AY38910::AY38910() :
_selected_register(0),
_tone_counters{0, 0, 0}, _tone_dividers{0, 0, 0},
_tone_counters{0, 0, 0}, _tone_dividers{0, 0, 0}, _tone_outputs{0, 0, 0},
_noise_shift_register(0xffff), _noise_divider(0), _noise_output(0),
_envelope_divider(0), _envelope_period(0), _envelope_position(0),
_output_registers{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
@ -82,14 +82,25 @@ void AY38910::set_clock_rate(double clock_rate)
void AY38910::get_samples(unsigned int number_of_samples, int16_t *target)
{
int offset = _master_divider;
int c = _master_divider;
_master_divider += number_of_samples;
for(; c < 16 && c < _master_divider; c++) target[c - offset] = _output_volume;
while(c < _master_divider)
int c = 0;
while((_master_divider&15) && c < number_of_samples)
{
#define step_channel(c) _tone_counters[c] = (_tone_counters[c] + 1) % (2 * (_tone_dividers[c] + 1))
target[c] = _output_volume;
_master_divider++;
c++;
}
while(c < number_of_samples)
{
#define step_channel(c) \
if(_tone_counters[c]) _tone_counters[c]--;\
else\
{\
_tone_outputs[c] ^= 1;\
_tone_counters[c] = _tone_dividers[c];\
}
// _tone_counters[c] = (_tone_counters[c] + 1) % (2 * (_tone_dividers[c] + 1))
// update the tone channels
step_channel(0);
@ -121,14 +132,13 @@ void AY38910::get_samples(unsigned int number_of_samples, int16_t *target)
evaluate_output_volume();
for(int ic = 0; ic < 16 && c < _master_divider; ic++)
for(int ic = 0; ic < 16 && c < number_of_samples; ic++)
{
target[c - offset] = _output_volume;
target[c] = _output_volume;
c++;
_master_divider++;
}
}
_master_divider &= 15;
}
void AY38910::evaluate_output_volume()
@ -140,7 +150,7 @@ void AY38910::evaluate_output_volume()
// 0 if either tone or noise is enabled and its value is low.
// (which is implemented here with reverse logic, assuming _channel_output and _noise_output are already inverted)
#define level(c, tb, nb) \
(((((_output_registers[7] >> tb)&1)^1) & (_tone_counters[c] / (_tone_dividers[c] + 1))) | ((((_output_registers[7] >> nb)&1)^1) & _noise_output)) ^ 1
(((((_output_registers[7] >> tb)&1)^1) & _tone_outputs[c]) | ((((_output_registers[7] >> nb)&1)^1) & _noise_output)) ^ 1
int channel_levels[3] = {
level(0, 0, 3),
@ -188,12 +198,13 @@ void AY38910::set_register_value(uint8_t value)
{
int channel = selected_register >> 1;
_tone_counters[channel] /= _tone_dividers[channel] + 1;
// _tone_counters[channel] /= _tone_dividers[channel] + 1;
if(selected_register & 1)
_tone_dividers[channel] = (_tone_dividers[channel] & 0xff) | (uint16_t)((value&0xf) << 8);
else
_tone_dividers[channel] = (_tone_dividers[channel] & ~0xff) | value;
_tone_counters[channel] *= _tone_dividers[channel] + 1;
// _tone_counters[channel] *= _tone_dividers[channel] + 1;
_tone_counters[channel] = _tone_dividers[channel];
}
break;

1
Components/AY38910/AY38910.hpp
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@ -56,6 +56,7 @@ class AY38910: public ::Outputs::Filter<AY38910> {
int _tone_dividers[3];
int _tone_counters[3];
int _tone_outputs[3];
int _volumes[16];