cog/Frameworks/GME/gme/Hes_Core.cpp

409 lines
9.2 KiB
C++

// Game_Music_Emu $vers. http://www.slack.net/~ant/
#include "Hes_Core.h"
#include "blargg_endian.h"
/* Copyright (C) 2006-2008 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"
int const timer_mask = 0x04;
int const vdp_mask = 0x02;
int const i_flag_mask = 0x04;
int const unmapped = 0xFF;
int const period_60hz = 262 * 455; // scanlines * clocks per scanline
Hes_Core::Hes_Core() : rom( Hes_Cpu::page_size )
{
timer.raw_load = 0;
}
Hes_Core::~Hes_Core() { }
void Hes_Core::unload()
{
rom.clear();
Gme_Loader::unload();
}
bool Hes_Core::header_t::valid_tag() const
{
return 0 == memcmp( tag, "HESM", 4 );
}
blargg_err_t Hes_Core::load_( Data_Reader& in )
{
assert( offsetof (header_t,unused [4]) == header_t::size );
RETURN_ERR( rom.load( in, header_t::size, &header_, unmapped ) );
if ( !header_.valid_tag() )
return blargg_err_file_type;
if ( header_.vers != 0 )
set_warning( "Unknown file version" );
if ( memcmp( header_.data_tag, "DATA", 4 ) )
set_warning( "Data header missing" );
if ( memcmp( header_.unused, "\0\0\0\0", 4 ) )
set_warning( "Unknown header data" );
// File spec supports multiple blocks, but I haven't found any, and
// many files have bad sizes in the only block, so it's simpler to
// just try to load the damn data as best as possible.
int addr = get_le32( header_.addr );
int size = get_le32( header_.data_size );
int const rom_max = 0x100000;
if ( (unsigned) addr >= (unsigned) rom_max )
{
set_warning( "Invalid address" );
addr &= rom_max - 1;
}
if ( (unsigned) (addr + size) > (unsigned) rom_max )
set_warning( "Invalid size" );
if ( size != rom.file_size() )
{
if ( size <= rom.file_size() - 4 && !memcmp( rom.begin() + size, "DATA", 4 ) )
set_warning( "Multiple DATA not supported" );
else if ( size < rom.file_size() )
set_warning( "Extra file data" );
else
set_warning( "Missing file data" );
}
rom.set_addr( addr );
return blargg_ok;
}
void Hes_Core::recalc_timer_load()
{
timer.load = timer.raw_load * timer_base + 1;
}
void Hes_Core::set_tempo( double t )
{
play_period = (time_t) (period_60hz / t);
timer_base = (int) (1024 / t);
recalc_timer_load();
}
blargg_err_t Hes_Core::start_track( int track )
{
memset( ram, 0, sizeof ram ); // some HES music relies on zero fill
memset( sgx, 0, sizeof sgx );
apu_.reset();
adpcm_.reset();
cpu.reset();
for ( int i = 0; i < (int) sizeof header_.banks; i++ )
set_mmr( i, header_.banks [i] );
set_mmr( cpu.page_count, 0xFF ); // unmapped beyond end of address space
irq.disables = timer_mask | vdp_mask;
irq.timer = cpu.future_time;
irq.vdp = cpu.future_time;
timer.enabled = false;
timer.raw_load = 0x80;
timer.count = timer.load;
timer.fired = false;
timer.last_time = 0;
vdp.latch = 0;
vdp.control = 0;
vdp.next_vbl = 0;
ram [0x1FF] = (idle_addr - 1) >> 8;
ram [0x1FE] = (idle_addr - 1) & 0xFF;
cpu.r.sp = 0xFD;
cpu.r.pc = get_le16( header_.init_addr );
cpu.r.a = track;
recalc_timer_load();
return blargg_ok;
}
// Hardware
void Hes_Core::run_until( time_t present )
{
while ( vdp.next_vbl < present )
vdp.next_vbl += play_period;
time_t elapsed = present - timer.last_time;
if ( elapsed > 0 )
{
if ( timer.enabled )
{
timer.count -= elapsed;
if ( timer.count <= 0 )
timer.count += timer.load;
}
timer.last_time = present;
}
}
void Hes_Core::write_vdp( int addr, int data )
{
switch ( addr )
{
case 0:
vdp.latch = data & 0x1F;
break;
case 2:
if ( vdp.latch == 5 )
{
if ( data & 0x04 )
set_warning( "Scanline interrupt unsupported" );
run_until( cpu.time() );
vdp.control = data;
irq_changed();
}
else
{
dprintf( "VDP not supported: $%02X <- $%02X\n", vdp.latch, data );
}
break;
case 3:
dprintf( "VDP MSB not supported: $%02X <- $%02X\n", vdp.latch, data );
break;
}
}
void Hes_Core::write_mem_( addr_t addr, int data )
{
time_t time = cpu.time();
if ( (unsigned) (addr - apu_.io_addr) < apu_.io_size )
{
// Avoid going way past end when a long block xfer is writing to I/O space.
// Not a problem for other registers below because they don't write to
// Blip_Buffer.
time_t t = min( time, cpu.end_time() + 8 );
apu_.write_data( t, addr, data );
return;
}
if ( (unsigned) (addr - adpcm_.io_addr) < adpcm_.io_size )
{
time_t t = min( time, cpu.end_time() + 6 );
adpcm_.write_data( t, addr, data );
return;
}
switch ( addr )
{
case 0x0000:
case 0x0002:
case 0x0003:
write_vdp( addr, data );
return;
case 0x0C00: {
run_until( time );
timer.raw_load = (data & 0x7F) + 1;
recalc_timer_load();
timer.count = timer.load;
break;
}
case 0x0C01:
data &= 1;
if ( timer.enabled == data )
return;
run_until( time );
timer.enabled = data;
if ( data )
timer.count = timer.load;
break;
case 0x1402:
run_until( time );
irq.disables = data;
if ( (data & 0xF8) && (data & 0xF8) != 0xF8 ) // flag questionable values
dprintf( "Int mask: $%02X\n", data );
break;
case 0x1403:
run_until( time );
if ( timer.enabled )
timer.count = timer.load;
timer.fired = false;
break;
#ifndef NDEBUG
case 0x1000: // I/O port
case 0x0402: // palette
case 0x0403:
case 0x0404:
case 0x0405:
return;
default:
dprintf( "unmapped write $%04X <- $%02X\n", addr, data );
return;
#endif
}
irq_changed();
}
int Hes_Core::read_mem_( addr_t addr )
{
time_t time = cpu.time();
addr &= cpu.page_size - 1;
switch ( addr )
{
case 0x0000:
if ( irq.vdp > time )
return 0;
irq.vdp = cpu.future_time;
run_until( time );
irq_changed();
return 0x20;
case 0x0002:
case 0x0003:
dprintf( "VDP read not supported: %d\n", addr );
return 0;
case 0x0C01:
//return timer.enabled; // TODO: remove?
case 0x0C00:
run_until( time );
dprintf( "Timer count read\n" );
return (unsigned) (timer.count - 1) / timer_base;
case 0x1402:
return irq.disables;
case 0x1403:
{
int status = 0;
if ( irq.timer <= time ) status |= timer_mask;
if ( irq.vdp <= time ) status |= vdp_mask;
return status;
}
case 0x180A:
case 0x180B:
case 0x180C:
case 0x180D:
return adpcm_.read_data( time, addr );
#ifndef NDEBUG
case 0x1000: // I/O port
//case 0x180C: // CD-ROM
//case 0x180D:
break;
default:
dprintf( "unmapped read $%04X\n", addr );
#endif
}
return unmapped;
}
void Hes_Core::irq_changed()
{
time_t present = cpu.time();
if ( irq.timer > present )
{
irq.timer = cpu.future_time;
if ( timer.enabled && !timer.fired )
irq.timer = present + timer.count;
}
if ( irq.vdp > present )
{
irq.vdp = cpu.future_time;
if ( vdp.control & 0x08 )
irq.vdp = vdp.next_vbl;
}
time_t time = cpu.future_time;
if ( !(irq.disables & timer_mask) ) time = irq.timer;
if ( !(irq.disables & vdp_mask) ) time = min( time, irq.vdp );
cpu.set_irq_time( time );
}
int Hes_Core::cpu_done()
{
check( cpu.time() >= cpu.end_time() ||
(!(cpu.r.flags & i_flag_mask) && cpu.time() >= cpu.irq_time()) );
if ( !(cpu.r.flags & i_flag_mask) )
{
time_t present = cpu.time();
if ( irq.timer <= present && !(irq.disables & timer_mask) )
{
timer.fired = true;
irq.timer = cpu.future_time;
irq_changed(); // overkill, but not worth writing custom code
return 0x0A;
}
if ( irq.vdp <= present && !(irq.disables & vdp_mask) )
{
// work around for bugs with music not acknowledging VDP
//run_until( present );
//irq.vdp = cpu.future_time;
//irq_changed();
return 0x08;
}
}
return -1;
}
static void adjust_time( Hes_Core::time_t& time, Hes_Core::time_t delta )
{
if ( time < Hes_Cpu::future_time )
{
time -= delta;
if ( time < 0 )
time = 0;
}
}
blargg_err_t Hes_Core::end_frame( time_t duration )
{
if ( run_cpu( duration ) )
set_warning( "Emulation error (illegal instruction)" );
check( cpu.time() >= duration );
//check( time() - duration < 20 ); // Txx instruction could cause going way over
run_until( duration );
// end time frame
timer.last_time -= duration;
vdp.next_vbl -= duration;
cpu.end_frame( duration );
::adjust_time( irq.timer, duration );
::adjust_time( irq.vdp, duration );
apu_.end_frame( duration );
adpcm_.end_frame( duration );
return blargg_ok;
}