cog/Frameworks/GME/gme/Nsf_Cpu.cpp

117 lines
3.0 KiB
C++

// Normal CPU for NSF emulator
// $package. http://www.slack.net/~ant/
#include "Nsf_Impl.h"
#include "blargg_endian.h"
#ifdef BLARGG_DEBUG_H
//#define CPU_LOG_START 1000000
//#include "nes_cpu_log.h"
#undef LOG_MEM
#endif
/* Copyright (C) 2003-2008 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"
#ifndef LOG_MEM
#define LOG_MEM( addr, str, data ) data
#endif
int Nsf_Impl::read_mem( addr_t addr )
{
int result = low_ram [addr & (low_ram_size-1)]; // also handles wrap-around
if ( addr & 0xE000 )
{
result = *cpu.get_code( addr );
if ( addr < sram_addr )
{
if ( addr == apu.status_addr )
result = apu.read_status( time() );
else
result = cpu_read( addr );
}
}
return LOG_MEM( addr, ">", result );
}
void Nsf_Impl::write_mem( addr_t addr, int data )
{
(void) LOG_MEM( addr, "<", data );
int offset = addr - sram_addr;
if ( (unsigned) offset < sram_size )
{
sram() [offset] = data;
}
else
{
// after sram because CPU handles most low_ram accesses internally already
int temp = addr & (low_ram_size-1); // also handles wrap-around
if ( !(addr & 0xE000) )
{
low_ram [temp] = data;
}
else
{
int bank = addr - banks_addr;
if ( (unsigned) bank < bank_count )
{
write_bank( bank, data );
}
else if ( (unsigned) (addr - apu.io_addr) < apu.io_size )
{
apu.write_register( time(), addr, data );
}
else
{
#if !NSF_EMU_APU_ONLY
// 0x8000-0xDFFF is writable
int i = addr - 0x8000;
if ( (unsigned) i < fdsram_size && fds_enabled() )
fdsram() [i] = data;
else
#endif
cpu_write( addr, data );
}
}
}
}
#define READ_LOW( addr ) (LOG_MEM( addr, ">", low_ram [addr] ))
#define WRITE_LOW( addr, data ) (LOG_MEM( addr, "<", low_ram [addr] = data ))
#define CAN_WRITE_FAST( addr ) (addr < low_ram_size)
#define WRITE_FAST WRITE_LOW
// addr < 0x2000 || addr >= 0x8000
#define CAN_READ_FAST( addr ) ((addr ^ 0x8000) < 0xA000)
#define READ_FAST( addr, out ) (LOG_MEM( addr, ">", out = READ_CODE( addr ) ))
#define READ_MEM( addr ) read_mem( addr )
#define WRITE_MEM( addr, data ) write_mem( addr, data )
#define CPU cpu
#define CPU_BEGIN \
bool Nsf_Impl::run_cpu_until( time_t end )\
{\
cpu.set_end_time( end );\
if ( *cpu.get_code( cpu.r.pc ) != cpu.halt_opcode )\
{
#include "Nes_Cpu_run.h"
}
return cpu.time_past_end() < 0;
}