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Diffstat (limited to 'plugins/gme/game-music-emu-0.5.5/gme/Snes_Spc.cpp')
-rw-r--r--plugins/gme/game-music-emu-0.5.5/gme/Snes_Spc.cpp489
1 files changed, 0 insertions, 489 deletions
diff --git a/plugins/gme/game-music-emu-0.5.5/gme/Snes_Spc.cpp b/plugins/gme/game-music-emu-0.5.5/gme/Snes_Spc.cpp
deleted file mode 100644
index d169b388..00000000
--- a/plugins/gme/game-music-emu-0.5.5/gme/Snes_Spc.cpp
+++ /dev/null
@@ -1,489 +0,0 @@
-// Game_Music_Emu 0.5.5. http://www.slack.net/~ant/
-
-#include "Snes_Spc.h"
-
-#include <string.h>
-
-/* Copyright (C) 2004-2006 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"
-
-// always in the future (CPU time can go over 0, but not by this much)
-int const timer_disabled_time = 127;
-
-Snes_Spc::Snes_Spc() : dsp( mem.ram ), cpu( this, mem.ram )
-{
- set_tempo( 1.0 );
-
- // Put STOP instruction around memory to catch PC underflow/overflow.
- memset( mem.padding1, 0xFF, sizeof mem.padding1 );
- memset( mem.padding2, 0xFF, sizeof mem.padding2 );
-
- // A few tracks read from the last four bytes of IPL ROM
- boot_rom [sizeof boot_rom - 2] = 0xC0;
- boot_rom [sizeof boot_rom - 1] = 0xFF;
- memset( boot_rom, 0, sizeof boot_rom - 2 );
-}
-
-void Snes_Spc::set_tempo( double t )
-{
- int unit = (int) (16.0 / t + 0.5);
-
- timer [0].divisor = unit * 8; // 8 kHz
- timer [1].divisor = unit * 8; // 8 kHz
- timer [2].divisor = unit; // 64 kHz
-}
-
-// Load
-
-void Snes_Spc::set_ipl_rom( void const* in )
-{
- memcpy( boot_rom, in, sizeof boot_rom );
-}
-
-blargg_err_t Snes_Spc::load_spc( const void* data, long size )
-{
- struct spc_file_t {
- char signature [27];
- char unused [10];
- uint8_t pc [2];
- uint8_t a;
- uint8_t x;
- uint8_t y;
- uint8_t status;
- uint8_t sp;
- char unused2 [212];
- uint8_t ram [0x10000];
- uint8_t dsp [128];
- uint8_t ipl_rom [128];
- };
- assert( offsetof (spc_file_t,ipl_rom) == spc_file_size );
-
- const spc_file_t* spc = (spc_file_t const*) data;
-
- if ( size < spc_file_size )
- return "Not an SPC file";
-
- if ( strncmp( spc->signature, "SNES-SPC700 Sound File Data", 27 ) != 0 )
- return "Not an SPC file";
-
- registers_t regs;
- regs.pc = spc->pc [1] * 0x100 + spc->pc [0];
- regs.a = spc->a;
- regs.x = spc->x;
- regs.y = spc->y;
- regs.status = spc->status;
- regs.sp = spc->sp;
-
- if ( (unsigned long) size >= sizeof *spc )
- set_ipl_rom( spc->ipl_rom );
-
- const char* error = load_state( regs, spc->ram, spc->dsp );
-
- echo_accessed = false;
-
- return error;
-}
-
-void Snes_Spc::clear_echo()
-{
- if ( !(dsp.read( 0x6C ) & 0x20) )
- {
- unsigned addr = 0x100 * dsp.read( 0x6D );
- size_t size = 0x800 * dsp.read( 0x7D );
- memset( mem.ram + addr, 0xFF, min( size, sizeof mem.ram - addr ) );
- }
-}
-
-// Handle other file formats (emulator save states) in user code, not here.
-
-blargg_err_t Snes_Spc::load_state( const registers_t& cpu_state, const void* new_ram,
- const void* dsp_state )
-{
- // cpu
- cpu.r = cpu_state;
-
- // Allow DSP to generate one sample before code starts
- // (Tengai Makyo Zero, Tenjin's Table Toss first notes are lost since it
- // clears KON 31 cycles from starting execution. It works on the SNES
- // since the SPC player adds a few extra cycles delay after restoring
- // KON from the DSP registers at the end of an SPC file).
- extra_cycles = 32;
-
- // ram
- memcpy( mem.ram, new_ram, sizeof mem.ram );
- memcpy( extra_ram, mem.ram + rom_addr, sizeof extra_ram );
-
- // boot rom (have to force enable_rom() to update it)
- rom_enabled = !(mem.ram [0xF1] & 0x80);
- enable_rom( !rom_enabled );
-
- // dsp
- dsp.reset();
- int i;
- for ( i = 0; i < Spc_Dsp::register_count; i++ )
- dsp.write( i, ((uint8_t const*) dsp_state) [i] );
-
- // timers
- for ( i = 0; i < timer_count; i++ )
- {
- Timer& t = timer [i];
-
- t.next_tick = 0;
- t.enabled = (mem.ram [0xF1] >> i) & 1;
- if ( !t.enabled )
- t.next_tick = timer_disabled_time;
- t.count = 0;
- t.counter = mem.ram [0xFD + i] & 15;
-
- int p = mem.ram [0xFA + i];
- t.period = p ? p : 0x100;
- }
-
- // Handle registers which already give 0 when read by setting RAM and not changing it.
- // Put STOP instruction in registers which can be read, to catch attempted CPU execution.
- mem.ram [0xF0] = 0;
- mem.ram [0xF1] = 0;
- mem.ram [0xF3] = 0xFF;
- mem.ram [0xFA] = 0;
- mem.ram [0xFB] = 0;
- mem.ram [0xFC] = 0;
- mem.ram [0xFD] = 0xFF;
- mem.ram [0xFE] = 0xFF;
- mem.ram [0xFF] = 0xFF;
-
- return 0; // success
-}
-
-// Hardware
-
-// Current time starts negative and ends at 0
-inline spc_time_t Snes_Spc::time() const
-{
- return -cpu.remain();
-}
-
-// Keep track of next time to run and avoid a function call if it hasn't been reached.
-
-// Timers
-
-void Snes_Spc::Timer::run_until_( spc_time_t time )
-{
- if ( !enabled )
- debug_printf( "next_tick: %ld, time: %ld", (long) next_tick, (long) time );
- assert( enabled ); // when disabled, next_tick should always be in the future
-
- int elapsed = ((time - next_tick) / divisor) + 1;
- next_tick += elapsed * divisor;
-
- elapsed += count;
- if ( elapsed >= period ) // avoid unnecessary division
- {
- int n = elapsed / period;
- elapsed -= n * period;
- counter = (counter + n) & 15;
- }
- count = elapsed;
-}
-
-// DSP
-
-const int clocks_per_sample = 32; // 1.024 MHz CPU clock / 32000 samples per second
-
-void Snes_Spc::run_dsp_( spc_time_t time )
-{
- int count = ((time - next_dsp) >> 5) + 1; // divide by clocks_per_sample
- sample_t* buf = sample_buf;
- if ( buf ) {
- sample_buf = buf + count * 2; // stereo
- assert( sample_buf <= buf_end );
- }
- next_dsp += count * clocks_per_sample;
- dsp.run( count, buf );
-}
-
-inline void Snes_Spc::run_dsp( spc_time_t time )
-{
- if ( time >= next_dsp )
- run_dsp_( time );
-}
-
-// Debug-only check for read/write within echo buffer, since this might result in
-// inaccurate emulation due to the DSP not being caught up to the present.
-inline void Snes_Spc::check_for_echo_access( spc_addr_t addr )
-{
- if ( !echo_accessed && !(dsp.read( 0x6C ) & 0x20) )
- {
- // ** If echo accesses are found that require running the DSP, cache
- // the start and end address on DSP writes to speed up checking.
-
- unsigned start = 0x100 * dsp.read( 0x6D );
- unsigned end = start + 0x800 * dsp.read( 0x7D );
- if ( start <= addr && addr < end ) {
- echo_accessed = true;
- debug_printf( "Read/write at $%04X within echo buffer\n", (unsigned) addr );
- }
- }
-}
-
-// Read
-
-int Snes_Spc::read( spc_addr_t addr )
-{
- int result = mem.ram [addr];
-
- if ( (rom_addr <= addr && addr < 0xFFFC || addr >= 0xFFFE) && rom_enabled )
- debug_printf( "Read from ROM: %04X -> %02X\n", addr, result );
-
- if ( unsigned (addr - 0xF0) < 0x10 )
- {
- assert( 0xF0 <= addr && addr <= 0xFF );
-
- // counters
- int i = addr - 0xFD;
- if ( i >= 0 )
- {
- Timer& t = timer [i];
- t.run_until( time() );
- int old = t.counter;
- t.counter = 0;
- return old;
- }
-
- // dsp
- if ( addr == 0xF3 )
- {
- run_dsp( time() );
- if ( mem.ram [0xF2] >= Spc_Dsp::register_count )
- debug_printf( "DSP read from $%02X\n", (int) mem.ram [0xF2] );
- return dsp.read( mem.ram [0xF2] & 0x7F );
- }
-
- if ( addr == 0xF0 || addr == 0xF1 || addr == 0xF8 ||
- addr == 0xF9 || addr == 0xFA )
- debug_printf( "Read from register $%02X\n", (int) addr );
-
- // Registers which always read as 0 are handled by setting mem.ram [reg] to 0
- // at startup then never changing that value.
-
- check(( check_for_echo_access( addr ), true ));
- }
-
- return result;
-}
-
-
-// Write
-
-void Snes_Spc::enable_rom( bool enable )
-{
- if ( rom_enabled != enable )
- {
- rom_enabled = enable;
- memcpy( mem.ram + rom_addr, (enable ? boot_rom : extra_ram), rom_size );
- // TODO: ROM can still get overwritten when DSP writes to echo buffer
- }
-}
-
-void Snes_Spc::write( spc_addr_t addr, int data )
-{
- // first page is very common
- if ( addr < 0xF0 ) {
- mem.ram [addr] = (uint8_t) data;
- }
- else switch ( addr )
- {
- // RAM
- default:
- check(( check_for_echo_access( addr ), true ));
- if ( addr < rom_addr ) {
- mem.ram [addr] = (uint8_t) data;
- }
- else {
- extra_ram [addr - rom_addr] = (uint8_t) data;
- if ( !rom_enabled )
- mem.ram [addr] = (uint8_t) data;
- }
- break;
-
- // DSP
- //case 0xF2: // mapped to RAM
- case 0xF3: {
- run_dsp( time() );
- int reg = mem.ram [0xF2];
- if ( next_dsp > 0 ) {
- // skip mode
-
- // key press
- if ( reg == 0x4C )
- keys_pressed |= data & ~dsp.read( 0x5C );
-
- // key release
- if ( reg == 0x5C ) {
- keys_released |= data;
- keys_pressed &= ~data;
- }
- }
- if ( reg < Spc_Dsp::register_count ) {
- dsp.write( reg, data );
- }
- else {
- debug_printf( "DSP write to $%02X\n", (int) reg );
- }
- break;
- }
-
- case 0xF0: // Test register
- debug_printf( "Wrote $%02X to $F0\n", (int) data );
- break;
-
- // Config
- case 0xF1:
- {
- // timers
- for ( int i = 0; i < timer_count; i++ )
- {
- Timer& t = timer [i];
- if ( !(data & (1 << i)) ) {
- t.enabled = 0;
- t.next_tick = timer_disabled_time;
- }
- else if ( !t.enabled ) {
- // just enabled
- t.enabled = 1;
- t.counter = 0;
- t.count = 0;
- t.next_tick = time();
- }
- }
-
- // port clears
- if ( data & 0x10 ) {
- mem.ram [0xF4] = 0;
- mem.ram [0xF5] = 0;
- }
- if ( data & 0x20 ) {
- mem.ram [0xF6] = 0;
- mem.ram [0xF7] = 0;
- }
-
- enable_rom( (data & 0x80) != 0 );
-
- break;
- }
-
- // Ports
- case 0xF4:
- case 0xF5:
- case 0xF6:
- case 0xF7:
- // to do: handle output ports
- break;
-
- //case 0xF8: // verified on SNES that these are read/write (RAM)
- //case 0xF9:
-
- // Timers
- case 0xFA:
- case 0xFB:
- case 0xFC: {
- Timer& t = timer [addr - 0xFA];
- if ( (t.period & 0xFF) != data ) {
- t.run_until( time() );
- t.period = data ? data : 0x100;
- }
- break;
- }
-
- // Counters (cleared on write)
- case 0xFD:
- case 0xFE:
- case 0xFF:
- debug_printf( "Wrote to counter $%02X\n", (int) addr );
- timer [addr - 0xFD].counter = 0;
- break;
- }
-}
-
-// Play
-
-blargg_err_t Snes_Spc::skip( long count )
-{
- if ( count > 4 * 32000L )
- {
- // don't run DSP for long durations (2-3 times faster)
-
- const long sync_count = 32000L * 2;
-
- // keep track of any keys pressed/released (and not subsequently released)
- keys_pressed = 0;
- keys_released = 0;
- // sentinel tells play to ignore DSP
- RETURN_ERR( play( count - sync_count, skip_sentinel ) );
-
- // press/release keys now
- dsp.write( 0x5C, keys_released & ~keys_pressed );
- dsp.write( 0x4C, keys_pressed );
-
- clear_echo();
-
- // play the last few seconds normally to help synchronize DSP
- count = sync_count;
- }
-
- return play( count );
-}
-
-blargg_err_t Snes_Spc::play( long count, sample_t* out )
-{
- require( count % 2 == 0 ); // output is always in pairs of samples
-
- // CPU time() runs from -duration to 0
- spc_time_t duration = (count / 2) * clocks_per_sample;
-
- // DSP output is made on-the-fly when the CPU reads/writes DSP registers
- sample_buf = out;
- buf_end = out + (out && out != skip_sentinel ? count : 0);
- next_dsp = (out == skip_sentinel) ? clocks_per_sample : -duration + clocks_per_sample;
-
- // Localize timer next_tick times and run them to the present to prevent a running
- // but ignored timer's next_tick from getting too far behind and overflowing.
- for ( int i = 0; i < timer_count; i++ )
- {
- Timer& t = timer [i];
- if ( t.enabled )
- {
- t.next_tick -= duration;
- t.run_until( -duration );
- }
- }
-
- // Run CPU for duration, reduced by any extra cycles from previous run
- int elapsed = cpu.run( duration - extra_cycles );
- if ( elapsed > 0 )
- {
- debug_printf( "Unhandled instruction $%02X, pc = $%04X\n",
- (int) cpu.read( cpu.r.pc ), (unsigned) cpu.r.pc );
- return "Emulation error (illegal/unsupported instruction)";
- }
- extra_cycles = -elapsed;
-
- // Catch DSP up to present.
- run_dsp( 0 );
- if ( out ) {
- assert( next_dsp == clocks_per_sample );
- assert( out == skip_sentinel || sample_buf - out == count );
- }
- buf_end = 0;
-
- return 0;
-}
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