mirror of
https://github.com/ZDoom/qzdoom.git
synced 2024-11-29 23:41:48 +00:00
121 lines
3.3 KiB
C++
121 lines
3.3 KiB
C++
// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
|
|
|
|
#include "Nes_Fme7_Apu.h"
|
|
|
|
#include <string.h>
|
|
|
|
/* Copyright (C) 2003-2006 Shay Green. This module is free software; you
|
|
can redistribute it and/or modify it under the terms of the GNU Lesser
|
|
General Public License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version. This
|
|
module is distributed in the hope that it will be useful, but WITHOUT ANY
|
|
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
|
|
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
|
|
details. You should have received a copy of the GNU Lesser General Public
|
|
License along with this module; if not, write to the Free Software Foundation,
|
|
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
|
|
|
|
#include "blargg_source.h"
|
|
|
|
void Nes_Fme7_Apu::reset()
|
|
{
|
|
last_time = 0;
|
|
|
|
for ( int i = 0; i < osc_count; i++ )
|
|
oscs [i].last_amp = 0;
|
|
|
|
fme7_apu_state_t* state = this;
|
|
memset( state, 0, sizeof *state );
|
|
}
|
|
|
|
unsigned char const Nes_Fme7_Apu::amp_table [16] =
|
|
{
|
|
#define ENTRY( n ) (unsigned char) (n * amp_range + 0.5)
|
|
ENTRY(0.0000), ENTRY(0.0078), ENTRY(0.0110), ENTRY(0.0156),
|
|
ENTRY(0.0221), ENTRY(0.0312), ENTRY(0.0441), ENTRY(0.0624),
|
|
ENTRY(0.0883), ENTRY(0.1249), ENTRY(0.1766), ENTRY(0.2498),
|
|
ENTRY(0.3534), ENTRY(0.4998), ENTRY(0.7070), ENTRY(1.0000)
|
|
#undef ENTRY
|
|
};
|
|
|
|
void Nes_Fme7_Apu::run_until( blip_time_t end_time )
|
|
{
|
|
require( end_time >= last_time );
|
|
|
|
for ( int index = 0; index < osc_count; index++ )
|
|
{
|
|
int mode = regs [7] >> index;
|
|
int vol_mode = regs [010 + index];
|
|
int volume = amp_table [vol_mode & 0x0F];
|
|
|
|
Blip_Buffer* const osc_output = oscs [index].output;
|
|
if ( !osc_output )
|
|
continue;
|
|
osc_output->set_modified();
|
|
|
|
// check for unsupported mode
|
|
#ifndef NDEBUG
|
|
if ( (mode & 011) <= 001 && vol_mode & 0x1F )
|
|
debug_printf( "FME7 used unimplemented sound mode: %02X, vol_mode: %02X\n",
|
|
mode, vol_mode & 0x1F );
|
|
#endif
|
|
|
|
if ( (mode & 001) | (vol_mode & 0x10) )
|
|
volume = 0; // noise and envelope aren't supported
|
|
|
|
// period
|
|
int const period_factor = 16;
|
|
unsigned period = (regs [index * 2 + 1] & 0x0F) * 0x100 * period_factor +
|
|
regs [index * 2] * period_factor;
|
|
if ( period < 50 ) // around 22 kHz
|
|
{
|
|
volume = 0;
|
|
if ( !period ) // on my AY-3-8910A, period doesn't have extra one added
|
|
period = period_factor;
|
|
}
|
|
|
|
// current amplitude
|
|
int amp = volume;
|
|
if ( !phases [index] )
|
|
amp = 0;
|
|
{
|
|
int delta = amp - oscs [index].last_amp;
|
|
if ( delta )
|
|
{
|
|
oscs [index].last_amp = amp;
|
|
synth.offset( last_time, delta, osc_output );
|
|
}
|
|
}
|
|
|
|
blip_time_t time = last_time + delays [index];
|
|
if ( time < end_time )
|
|
{
|
|
int delta = amp * 2 - volume;
|
|
if ( volume )
|
|
{
|
|
do
|
|
{
|
|
delta = -delta;
|
|
synth.offset_inline( time, delta, osc_output );
|
|
time += period;
|
|
}
|
|
while ( time < end_time );
|
|
|
|
oscs [index].last_amp = (delta + volume) >> 1;
|
|
phases [index] = (delta > 0);
|
|
}
|
|
else
|
|
{
|
|
// maintain phase when silent
|
|
int count = (end_time - time + period - 1) / period;
|
|
phases [index] ^= count & 1;
|
|
time += (blargg_long) count * period;
|
|
}
|
|
}
|
|
|
|
delays [index] = time - end_time;
|
|
}
|
|
|
|
last_time = end_time;
|
|
}
|
|
|