raze-gles/libraries/game-music-emu/gme/Snes_Spc.cpp
Christoph Oelckers 718112a8fe - added external libraries for music format playback and decompression from GZDoom.
Currently none of these is being used, but eventually they will, once more code gets ported over.
So it's better to have them right away and avoid editing the project file too much, only to revert that later.
2019-09-22 08:59:48 +02:00

380 lines
9.3 KiB
C++

// SPC emulation support: init, sample buffering, reset, SPC loading
// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
#include "Snes_Spc.h"
#include <string.h>
/* Copyright (C) 2004-2007 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"
#define RAM (m.ram.ram)
#define REGS (m.smp_regs [0])
#define REGS_IN (m.smp_regs [1])
// (n ? n : 256)
#define IF_0_THEN_256( n ) ((uint8_t) ((n) - 1) + 1)
//// Init
blargg_err_t Snes_Spc::init()
{
memset( &m, 0, sizeof m );
dsp.init( RAM );
m.tempo = tempo_unit;
// Most SPC music doesn't need ROM, and almost all the rest only rely
// on these two bytes
m.rom [0x3E] = 0xFF;
m.rom [0x3F] = 0xC0;
static unsigned char const cycle_table [128] =
{// 01 23 45 67 89 AB CD EF
0x28,0x47,0x34,0x36,0x26,0x54,0x54,0x68, // 0
0x48,0x47,0x45,0x56,0x55,0x65,0x22,0x46, // 1
0x28,0x47,0x34,0x36,0x26,0x54,0x54,0x74, // 2
0x48,0x47,0x45,0x56,0x55,0x65,0x22,0x38, // 3
0x28,0x47,0x34,0x36,0x26,0x44,0x54,0x66, // 4
0x48,0x47,0x45,0x56,0x55,0x45,0x22,0x43, // 5
0x28,0x47,0x34,0x36,0x26,0x44,0x54,0x75, // 6
0x48,0x47,0x45,0x56,0x55,0x55,0x22,0x36, // 7
0x28,0x47,0x34,0x36,0x26,0x54,0x52,0x45, // 8
0x48,0x47,0x45,0x56,0x55,0x55,0x22,0xC5, // 9
0x38,0x47,0x34,0x36,0x26,0x44,0x52,0x44, // A
0x48,0x47,0x45,0x56,0x55,0x55,0x22,0x34, // B
0x38,0x47,0x45,0x47,0x25,0x64,0x52,0x49, // C
0x48,0x47,0x56,0x67,0x45,0x55,0x22,0x83, // D
0x28,0x47,0x34,0x36,0x24,0x53,0x43,0x40, // E
0x48,0x47,0x45,0x56,0x34,0x54,0x22,0x60, // F
};
// unpack cycle table
for ( int i = 0; i < 128; i++ )
{
int n = cycle_table [i];
m.cycle_table [i * 2 + 0] = n >> 4;
m.cycle_table [i * 2 + 1] = n & 0x0F;
}
#if SPC_LESS_ACCURATE
memcpy( reg_times, reg_times_, sizeof reg_times );
#endif
reset();
return 0;
}
void Snes_Spc::init_rom( uint8_t const in [rom_size] )
{
memcpy( m.rom, in, sizeof m.rom );
}
void Snes_Spc::set_tempo( int t )
{
m.tempo = t;
int const timer2_shift = 4; // 64 kHz
int const other_shift = 3; // 8 kHz
#if SPC_DISABLE_TEMPO
m.timers [2].prescaler = timer2_shift;
m.timers [1].prescaler = timer2_shift + other_shift;
m.timers [0].prescaler = timer2_shift + other_shift;
#else
if ( !t )
t = 1;
int const timer2_rate = 1 << timer2_shift;
int rate = (timer2_rate * tempo_unit + (t >> 1)) / t;
if ( rate < timer2_rate / 4 )
rate = timer2_rate / 4; // max 4x tempo
m.timers [2].prescaler = rate;
m.timers [1].prescaler = rate << other_shift;
m.timers [0].prescaler = rate << other_shift;
#endif
}
// Timer registers have been loaded. Applies these to the timers. Does not
// reset timer prescalers or dividers.
void Snes_Spc::timers_loaded()
{
int i;
for ( i = 0; i < timer_count; i++ )
{
Timer* t = &m.timers [i];
t->period = IF_0_THEN_256( REGS [r_t0target + i] );
t->enabled = REGS [r_control] >> i & 1;
t->counter = REGS_IN [r_t0out + i] & 0x0F;
}
set_tempo( m.tempo );
}
// Loads registers from unified 16-byte format
void Snes_Spc::load_regs( uint8_t const in [reg_count] )
{
memcpy( REGS, in, reg_count );
memcpy( REGS_IN, REGS, reg_count );
// These always read back as 0
REGS_IN [r_test ] = 0;
REGS_IN [r_control ] = 0;
REGS_IN [r_t0target] = 0;
REGS_IN [r_t1target] = 0;
REGS_IN [r_t2target] = 0;
}
// RAM was just loaded from SPC, with $F0-$FF containing SMP registers
// and timer counts. Copies these to proper registers.
void Snes_Spc::ram_loaded()
{
m.rom_enabled = 0;
load_regs( &RAM [0xF0] );
// Put STOP instruction around memory to catch PC underflow/overflow
memset( m.ram.padding1, cpu_pad_fill, sizeof m.ram.padding1 );
memset( m.ram.ram + 0x10000, cpu_pad_fill, sizeof m.ram.padding1 );
}
// Registers were just loaded. Applies these new values.
void Snes_Spc::regs_loaded()
{
enable_rom( REGS [r_control] & 0x80 );
timers_loaded();
}
void Snes_Spc::reset_time_regs()
{
m.cpu_error = 0;
m.echo_accessed = 0;
m.spc_time = 0;
m.dsp_time = 0;
#if SPC_LESS_ACCURATE
m.dsp_time = clocks_per_sample + 1;
#endif
for ( int i = 0; i < timer_count; i++ )
{
Timer* t = &m.timers [i];
t->next_time = 1;
t->divider = 0;
}
regs_loaded();
m.extra_clocks = 0;
reset_buf();
}
void Snes_Spc::reset_common( int timer_counter_init )
{
int i;
for ( i = 0; i < timer_count; i++ )
REGS_IN [r_t0out + i] = timer_counter_init;
// Run IPL ROM
memset( &m.cpu_regs, 0, sizeof m.cpu_regs );
m.cpu_regs.pc = rom_addr;
REGS [r_test ] = 0x0A;
REGS [r_control] = 0xB0; // ROM enabled, clear ports
for ( i = 0; i < port_count; i++ )
REGS_IN [r_cpuio0 + i] = 0;
reset_time_regs();
}
void Snes_Spc::soft_reset()
{
reset_common( 0 );
dsp.soft_reset();
}
void Snes_Spc::reset()
{
memset( RAM, 0xFF, 0x10000 );
ram_loaded();
reset_common( 0x0F );
dsp.reset();
}
char const Snes_Spc::signature [signature_size + 1] =
"SNES-SPC700 Sound File Data v0.30\x1A\x1A";
blargg_err_t Snes_Spc::load_spc( void const* data, long size )
{
spc_file_t const* const spc = (spc_file_t const*) data;
// be sure compiler didn't insert any padding into fle_t
assert( sizeof (spc_file_t) == spc_min_file_size + 0x80 );
// Check signature and file size
if ( size < signature_size || memcmp( spc, signature, 27 ) )
return "Not an SPC file";
if ( size < spc_min_file_size )
return "Corrupt SPC file";
// CPU registers
m.cpu_regs.pc = spc->pch * 0x100 + spc->pcl;
m.cpu_regs.a = spc->a;
m.cpu_regs.x = spc->x;
m.cpu_regs.y = spc->y;
m.cpu_regs.psw = spc->psw;
m.cpu_regs.sp = spc->sp;
// RAM and registers
memcpy( RAM, spc->ram, 0x10000 );
ram_loaded();
// DSP registers
dsp.load( spc->dsp );
reset_time_regs();
return 0;
}
void Snes_Spc::clear_echo()
{
if ( !(dsp.read( Spc_Dsp::r_flg ) & 0x20) )
{
int addr = 0x100 * dsp.read( Spc_Dsp::r_esa );
int end = addr + 0x800 * (dsp.read( Spc_Dsp::r_edl ) & 0x0F);
if ( end > 0x10000 )
end = 0x10000;
memset( &RAM [addr], 0xFF, end - addr );
}
}
//// Sample output
void Snes_Spc::reset_buf()
{
// Start with half extra buffer of silence
sample_t* out = m.extra_buf;
while ( out < &m.extra_buf [extra_size / 2] )
*out++ = 0;
m.extra_pos = out;
m.buf_begin = 0;
dsp.set_output( 0, 0 );
}
void Snes_Spc::set_output( sample_t* out, int size )
{
require( (size & 1) == 0 ); // size must be even
m.extra_clocks &= clocks_per_sample - 1;
if ( out )
{
sample_t const* out_end = out + size;
m.buf_begin = out;
m.buf_end = out_end;
// Copy extra to output
sample_t const* in = m.extra_buf;
while ( in < m.extra_pos && out < out_end )
*out++ = *in++;
// Handle output being full already
if ( out >= out_end )
{
// Have DSP write to remaining extra space
out = dsp.extra();
out_end = &dsp.extra() [extra_size];
// Copy any remaining extra samples as if DSP wrote them
while ( in < m.extra_pos )
*out++ = *in++;
assert( out <= out_end );
}
dsp.set_output( out, out_end - out );
}
else
{
reset_buf();
}
}
void Snes_Spc::save_extra()
{
// Get end pointers
sample_t const* main_end = m.buf_end; // end of data written to buf
sample_t const* dsp_end = dsp.out_pos(); // end of data written to dsp.extra()
if ( m.buf_begin <= dsp_end && dsp_end <= main_end )
{
main_end = dsp_end;
dsp_end = dsp.extra(); // nothing in DSP's extra
}
// Copy any extra samples at these ends into extra_buf
sample_t* out = m.extra_buf;
sample_t const* in;
for ( in = m.buf_begin + sample_count(); in < main_end; in++ )
*out++ = *in;
for ( in = dsp.extra(); in < dsp_end ; in++ )
*out++ = *in;
m.extra_pos = out;
assert( out <= &m.extra_buf [extra_size] );
}
blargg_err_t Snes_Spc::play( int count, sample_t* out )
{
require( (count & 1) == 0 ); // must be even
if ( count )
{
set_output( out, count );
end_frame( count * (clocks_per_sample / 2) );
}
const char* err = m.cpu_error;
m.cpu_error = 0;
return err;
}
blargg_err_t Snes_Spc::skip( int count )
{
#if SPC_LESS_ACCURATE
if ( count > 2 * sample_rate * 2 )
{
set_output( 0, 0 );
// Skip a multiple of 4 samples
time_t end = count;
count = (count & 3) + 1 * sample_rate * 2;
end = (end - count) * (clocks_per_sample / 2);
m.skipped_kon = 0;
m.skipped_koff = 0;
// Preserve DSP and timer synchronization
// TODO: verify that this really preserves it
int old_dsp_time = m.dsp_time + m.spc_time;
m.dsp_time = end - m.spc_time + skipping_time;
end_frame( end );
m.dsp_time = m.dsp_time - skipping_time + old_dsp_time;
dsp.write( Spc_Dsp::r_koff, m.skipped_koff & ~m.skipped_kon );
dsp.write( Spc_Dsp::r_kon , m.skipped_kon );
clear_echo();
}
#endif
return play( count, 0 );
}