116 lines
3.2 KiB
C
116 lines
3.2 KiB
C
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// Normal cpu for NSF emulator
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// Game_Music_Emu 0.6-pre. http://www.slack.net/~ant/
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#include "nsf_emu.h"
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#include "blargg_endian.h"
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#ifdef BLARGG_DEBUG_H
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//#define CPU_LOG_START 1000000
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//#include "nes_cpu_log.h"
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#undef LOG_MEM
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#endif
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/* Copyright (C) 2003-2008 Shay Green. This module is free software; you
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can redistribute it and/or modify it under the terms of the GNU Lesser
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General Public License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version. This
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module is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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details. You should have received a copy of the GNU Lesser General Public
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License along with this module; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
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#include "blargg_source.h"
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#ifndef LOG_MEM
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#define LOG_MEM( addr, str, data ) data
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#endif
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int read_mem( struct Nsf_Emu* this, addr_t addr )
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{
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int result = this->low_ram [addr & (low_ram_size-1)]; // also handles wrap-around
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if ( addr & 0xE000 )
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{
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result = *Cpu_get_code( &this->cpu, addr );
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if ( addr < sram_addr )
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{
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if ( addr == apu_status_addr )
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result = Apu_read_status( &this->apu, Cpu_time( &this->cpu ) );
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else
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result = cpu_read( this, addr );
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}
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}
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return LOG_MEM( addr, ">", result );
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}
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void write_mem( struct Nsf_Emu* this, addr_t addr, int data )
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{
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(void) LOG_MEM( addr, "<", data );
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int offset = addr - sram_addr;
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if ( (unsigned) offset < sram_size )
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{
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sram( this ) [offset] = data;
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}
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else
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{
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// after sram because cpu handles most low_ram accesses internally already
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int temp = addr & (low_ram_size-1); // also handles wrap-around
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if ( !(addr & 0xE000) )
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{
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this->low_ram [temp] = data;
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}
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else
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{
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int bank = addr - banks_addr;
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if ( (unsigned) bank < bank_count )
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{
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write_bank( this, bank, data );
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}
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else if ( (unsigned) (addr - apu_io_addr) < apu_io_size )
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{
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Apu_write_register( &this->apu, Cpu_time( &this->cpu ), addr, data );
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}
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else
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{
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#ifndef NSF_EMU_APU_ONLY
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// 0x8000-0xDFFF is writable
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int i = addr - 0x8000;
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if ( fds_enabled( this ) && (unsigned) i < fdsram_size )
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fdsram( this ) [i] = data;
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else
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#endif
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cpu_write( this, addr, data );
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}
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}
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}
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}
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#define READ_LOW( addr ) (LOG_MEM( addr, ">", this->low_ram [addr] ))
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#define WRITE_LOW( addr, data ) (LOG_MEM( addr, "<", this->low_ram [addr] = data ))
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#define CAN_WRITE_FAST( addr ) (addr < low_ram_size)
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#define WRITE_FAST WRITE_LOW
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// addr < 0x2000 || addr >= 0x8000
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#define CAN_READ_FAST( addr ) ((addr ^ 0x8000) < 0xA000)
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#define READ_FAST( addr, out ) (LOG_MEM( addr, ">", out = READ_CODE( addr ) ))
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#define READ_MEM( addr ) read_mem( this, addr )
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#define WRITE_MEM( addr, data ) write_mem( this, addr, data )
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#define CPU_BEGIN \
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bool run_cpu_until( struct Nsf_Emu* this, nes_time_t end ) \
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{ \
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struct Nes_Cpu* cpu = &this->cpu; \
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Cpu_set_end_time( cpu, end ); \
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if ( *Cpu_get_code( cpu, cpu->r.pc ) != halt_opcode ) \
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{
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#include "nes_cpu_run.h"
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}
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return Cpu_time_past_end( cpu ) < 0;
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}
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