raze/libraries/game-music-emu/gme/Ay_Emu.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

405 lines
9.8 KiB
C++

// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
#include "Ay_Emu.h"
#include "blargg_endian.h"
#include <string.h>
/* Copyright (C) 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"
long const spectrum_clock = 3546900;
long const cpc_clock = 2000000;
unsigned const ram_start = 0x4000;
int const osc_count = Ay_Apu::osc_count + 1;
Ay_Emu::Ay_Emu()
{
beeper_output = 0;
set_type( gme_ay_type );
static const char* const names [osc_count] = {
"Wave 1", "Wave 2", "Wave 3", "Beeper"
};
set_voice_names( names );
static int const types [osc_count] = {
wave_type | 0, wave_type | 1, wave_type | 2, mixed_type | 0
};
set_voice_types( types );
set_silence_lookahead( 6 );
}
Ay_Emu::~Ay_Emu() { }
// Track info
static byte const* get_data( Ay_Emu::file_t const& file, byte const* ptr, int min_size )
{
long pos = ptr - (byte const*) file.header;
long file_size = file.end - (byte const*) file.header;
assert( (unsigned long) pos <= (unsigned long) file_size - 2 );
int offset = (int16_t) get_be16( ptr );
if ( !offset || blargg_ulong (pos + offset) > blargg_ulong (file_size - min_size) )
return 0;
return ptr + offset;
}
static blargg_err_t parse_header( byte const* in, long size, Ay_Emu::file_t* out )
{
typedef Ay_Emu::header_t header_t;
out->header = (header_t const*) in;
out->end = in + size;
if ( size < Ay_Emu::header_size )
return gme_wrong_file_type;
header_t const& h = *(header_t const*) in;
if ( memcmp( h.tag, "ZXAYEMUL", 8 ) )
return gme_wrong_file_type;
out->tracks = get_data( *out, h.track_info, (h.max_track + 1) * 4 );
if ( !out->tracks )
return "Missing track data";
return 0;
}
static void copy_ay_fields( Ay_Emu::file_t const& file, track_info_t* out, int track )
{
Gme_File::copy_field_( out->song, (char const*) get_data( file, file.tracks + track * 4, 1 ) );
byte const* track_info = get_data( file, file.tracks + track * 4 + 2, 6 );
if ( track_info )
out->length = get_be16( track_info + 4 ) * (1000L / 50); // frames to msec
Gme_File::copy_field_( out->author, (char const*) get_data( file, file.header->author, 1 ) );
Gme_File::copy_field_( out->comment, (char const*) get_data( file, file.header->comment, 1 ) );
}
blargg_err_t Ay_Emu::track_info_( track_info_t* out, int track ) const
{
copy_ay_fields( file, out, track );
return 0;
}
struct Ay_File : Gme_Info_
{
Ay_Emu::file_t file;
Ay_File() { set_type( gme_ay_type ); }
blargg_err_t load_mem_( byte const* begin, long size )
{
RETURN_ERR( parse_header( begin, size, &file ) );
set_track_count( file.header->max_track + 1 );
return 0;
}
blargg_err_t track_info_( track_info_t* out, int track ) const
{
copy_ay_fields( file, out, track );
return 0;
}
};
static Music_Emu* new_ay_emu () { return BLARGG_NEW Ay_Emu ; }
static Music_Emu* new_ay_file() { return BLARGG_NEW Ay_File; }
static gme_type_t_ const gme_ay_type_ = { "ZX Spectrum", 0, &new_ay_emu, &new_ay_file, "AY", 1 };
BLARGG_EXPORT extern gme_type_t const gme_ay_type = &gme_ay_type_;
// Setup
blargg_err_t Ay_Emu::load_mem_( byte const* in, long size )
{
assert( offsetof (header_t,track_info [2]) == header_size );
RETURN_ERR( parse_header( in, size, &file ) );
set_track_count( file.header->max_track + 1 );
if ( file.header->vers > 2 )
set_warning( "Unknown file version" );
set_voice_count( osc_count );
apu.volume( gain() );
return setup_buffer( spectrum_clock );
}
void Ay_Emu::update_eq( blip_eq_t const& eq )
{
apu.treble_eq( eq );
}
void Ay_Emu::set_voice( int i, Blip_Buffer* center, Blip_Buffer*, Blip_Buffer* )
{
if ( i >= Ay_Apu::osc_count )
beeper_output = center;
else
apu.osc_output( i, center );
}
// Emulation
void Ay_Emu::set_tempo_( double t )
{
play_period = blip_time_t (clock_rate() / 50 / t);
}
blargg_err_t Ay_Emu::start_track_( int track )
{
RETURN_ERR( Classic_Emu::start_track_( track ) );
memset( mem.ram + 0x0000, 0xC9, 0x100 ); // fill RST vectors with RET
memset( mem.ram + 0x0100, 0xFF, 0x4000 - 0x100 );
memset( mem.ram + ram_start, 0x00, sizeof mem.ram - ram_start );
memset( mem.padding1, 0xFF, sizeof mem.padding1 );
memset( mem.ram + 0x10000, 0xFF, sizeof mem.ram - 0x10000 );
// locate data blocks
byte const* const data = get_data( file, file.tracks + track * 4 + 2, 14 );
if ( !data ) return "File data missing";
byte const* const more_data = get_data( file, data + 10, 6 );
if ( !more_data ) return "File data missing";
byte const* blocks = get_data( file, data + 12, 8 );
if ( !blocks ) return "File data missing";
// initial addresses
cpu::reset( mem.ram );
r.sp = get_be16( more_data );
r.b.a = r.b.b = r.b.d = r.b.h = data [8];
r.b.flags = r.b.c = r.b.e = r.b.l = data [9];
r.alt.w = r.w;
r.ix = r.iy = r.w.hl;
unsigned addr = get_be16( blocks );
if ( !addr ) return "File data missing";
unsigned init = get_be16( more_data + 2 );
if ( !init )
init = addr;
// copy blocks into memory
do
{
blocks += 2;
unsigned len = get_be16( blocks ); blocks += 2;
if ( addr + len > 0x10000 )
{
set_warning( "Bad data block size" );
len = 0x10000 - addr;
}
check( len );
byte const* in = get_data( file, blocks, 0 ); blocks += 2;
if ( len > blargg_ulong (file.end - in) )
{
set_warning( "Missing file data" );
len = file.end - in;
}
//debug_printf( "addr: $%04X, len: $%04X\n", addr, len );
if ( addr < ram_start && addr >= 0x400 ) // several tracks use low data
debug_printf( "Block addr in ROM\n" );
memcpy( mem.ram + addr, in, len );
if ( file.end - blocks < 8 )
{
set_warning( "Missing file data" );
break;
}
}
while ( (addr = get_be16( blocks )) != 0 );
// copy and configure driver
static byte const passive [] = {
0xF3, // DI
0xCD, 0, 0, // CALL init
0xED, 0x5E, // LOOP: IM 2
0xFB, // EI
0x76, // HALT
0x18, 0xFA // JR LOOP
};
static byte const active [] = {
0xF3, // DI
0xCD, 0, 0, // CALL init
0xED, 0x56, // LOOP: IM 1
0xFB, // EI
0x76, // HALT
0xCD, 0, 0, // CALL play
0x18, 0xF7 // JR LOOP
};
memcpy( mem.ram, passive, sizeof passive );
unsigned play_addr = get_be16( more_data + 4 );
//debug_printf( "Play: $%04X\n", play_addr );
if ( play_addr )
{
memcpy( mem.ram, active, sizeof active );
mem.ram [ 9] = play_addr;
mem.ram [10] = play_addr >> 8;
}
mem.ram [2] = init;
mem.ram [3] = init >> 8;
mem.ram [0x38] = 0xFB; // Put EI at interrupt vector (followed by RET)
memcpy( mem.ram + 0x10000, mem.ram, 0x80 ); // some code wraps around (ugh)
beeper_delta = int (apu.amp_range * 0.65);
last_beeper = 0;
apu.reset();
next_play = play_period;
// start at spectrum speed
change_clock_rate( spectrum_clock );
set_tempo( tempo() );
spectrum_mode = false;
cpc_mode = false;
cpc_latch = 0;
return 0;
}
// Emulation
void Ay_Emu::cpu_out_misc( cpu_time_t time, unsigned addr, int data )
{
if ( !cpc_mode )
{
switch ( addr & 0xFEFF )
{
case 0xFEFD:
spectrum_mode = true;
apu_addr = data & 0x0F;
return;
case 0xBEFD:
spectrum_mode = true;
apu.write( time, apu_addr, data );
return;
}
}
if ( !spectrum_mode )
{
switch ( addr >> 8 )
{
case 0xF6:
switch ( data & 0xC0 )
{
case 0xC0:
apu_addr = cpc_latch & 0x0F;
goto enable_cpc;
case 0x80:
apu.write( time, apu_addr, cpc_latch );
goto enable_cpc;
}
break;
case 0xF4:
cpc_latch = data;
goto enable_cpc;
}
}
debug_printf( "Unmapped OUT: $%04X <- $%02X\n", addr, data );
return;
enable_cpc:
if ( !cpc_mode )
{
cpc_mode = true;
change_clock_rate( cpc_clock );
set_tempo( tempo() );
}
}
void ay_cpu_out( Ay_Cpu* cpu, cpu_time_t time, unsigned addr, int data )
{
Ay_Emu& emu = STATIC_CAST(Ay_Emu&,*cpu);
if ( (addr & 0xFF) == 0xFE && !emu.cpc_mode )
{
int delta = emu.beeper_delta;
data &= 0x10;
if ( emu.last_beeper != data )
{
emu.last_beeper = data;
emu.beeper_delta = -delta;
emu.spectrum_mode = true;
if ( emu.beeper_output )
emu.apu.synth_.offset( time, delta, emu.beeper_output );
}
}
else
{
emu.cpu_out_misc( time, addr, data );
}
}
int ay_cpu_in( Ay_Cpu*, unsigned addr )
{
// keyboard read and other things
if ( (addr & 0xFF) == 0xFE )
return 0xFF; // other values break some beeper tunes
debug_printf( "Unmapped IN : $%04X\n", addr );
return 0xFF;
}
blargg_err_t Ay_Emu::run_clocks( blip_time_t& duration, int )
{
set_time( 0 );
if ( !(spectrum_mode | cpc_mode) )
duration /= 2; // until mode is set, leave room for halved clock rate
while ( time() < duration )
{
cpu::run( min( duration, (blip_time_t) next_play ) );
if ( time() >= next_play )
{
next_play += play_period;
if ( r.iff1 )
{
if ( mem.ram [r.pc] == 0x76 )
r.pc++;
r.iff1 = r.iff2 = 0;
mem.ram [--r.sp] = uint8_t (r.pc >> 8);
mem.ram [--r.sp] = uint8_t (r.pc);
r.pc = 0x38;
cpu::adjust_time( 12 );
if ( r.im == 2 )
{
cpu::adjust_time( 6 );
unsigned addr = r.i * 0x100u + 0xFF;
r.pc = mem.ram [(addr + 1) & 0xFFFF] * 0x100u + mem.ram [addr];
}
}
}
}
duration = time();
next_play -= duration;
check( next_play >= 0 );
adjust_time( -duration );
apu.end_frame( duration );
return 0;
}