// Game_Music_Emu 0.6.0. http://www.slack.net/~ant/ #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 = long(ptr - (byte const*) file.header); long file_size = long(file.end - (byte const*) file.header); assert( (unsigned long) pos <= (unsigned long) file_size - 2 ); int offset = (BOOST::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 }; 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 = unsigned(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; }