mirror of
https://github.com/DrBeef/Raze.git
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1073 lines
21 KiB
C++
1073 lines
21 KiB
C++
// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
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#include "Nes_Cpu.h"
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#include "blargg_endian.h"
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#include <limits.h>
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#define BLARGG_CPU_X86 1
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/* Copyright (C) 2003-2006 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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#ifdef BLARGG_ENABLE_OPTIMIZER
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#include BLARGG_ENABLE_OPTIMIZER
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#endif
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#define FLUSH_TIME() (void) (s.time = s_time)
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#define CACHE_TIME() (void) (s_time = s.time)
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#include "nes_cpu_io.h"
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#include "blargg_source.h"
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#ifndef CPU_DONE
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#define CPU_DONE( cpu, time, result_out ) { result_out = -1; }
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#endif
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#ifndef CPU_READ_PPU
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#define CPU_READ_PPU( cpu, addr, out, time )\
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{\
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FLUSH_TIME();\
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out = CPU_READ( cpu, addr, time );\
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CACHE_TIME();\
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}
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#endif
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#if BLARGG_NONPORTABLE
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#define PAGE_OFFSET( addr ) (addr)
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#else
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#define PAGE_OFFSET( addr ) ((addr) & (page_size - 1))
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#endif
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inline void Nes_Cpu::set_code_page( int i, void const* p )
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{
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state->code_map [i] = (uint8_t const*) p - PAGE_OFFSET( i * page_size );
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}
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int const st_n = 0x80;
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int const st_v = 0x40;
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int const st_r = 0x20;
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int const st_b = 0x10;
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int const st_d = 0x08;
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int const st_i = 0x04;
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int const st_z = 0x02;
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int const st_c = 0x01;
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void Nes_Cpu::reset( void const* unmapped_page )
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{
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check( state == &state_ );
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state = &state_;
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r.status = st_i;
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r.sp = 0xFF;
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r.pc = 0;
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r.a = 0;
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r.x = 0;
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r.y = 0;
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state_.time = 0;
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state_.base = 0;
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irq_time_ = future_nes_time;
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end_time_ = future_nes_time;
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error_count_ = 0;
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assert( page_size == 0x800 ); // assumes this
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set_code_page( page_count, unmapped_page );
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map_code( 0x2000, 0xE000, unmapped_page, true );
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map_code( 0x0000, 0x2000, low_mem, true );
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blargg_verify_byte_order();
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}
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void Nes_Cpu::map_code( nes_addr_t start, unsigned size, void const* data, bool mirror )
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{
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// address range must begin and end on page boundaries
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require( start % page_size == 0 );
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require( size % page_size == 0 );
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require( start + size <= 0x10000 );
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unsigned page = start / page_size;
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for ( unsigned n = size / page_size; n; --n )
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{
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set_code_page( page++, data );
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if ( !mirror )
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data = (char const*) data + page_size;
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}
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}
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#define TIME (s_time + s.base)
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#define READ_LIKELY_PPU( addr, out ) {CPU_READ_PPU( this, (addr), out, TIME );}
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#define READ( addr ) CPU_READ( this, (addr), TIME )
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#define WRITE( addr, data ) {CPU_WRITE( this, (addr), (data), TIME );}
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#define READ_LOW( addr ) (low_mem [int (addr)])
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#define WRITE_LOW( addr, data ) (void) (READ_LOW( addr ) = (data))
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#define READ_PROG( addr ) (s.code_map [(addr) >> page_bits] [PAGE_OFFSET( addr )])
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#define SET_SP( v ) (sp = ((v) + 1) | 0x100)
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#define GET_SP() ((sp - 1) & 0xFF)
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#define PUSH( v ) ((sp = (sp - 1) | 0x100), WRITE_LOW( sp, v ))
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bool Nes_Cpu::run( nes_time_t end_time )
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{
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set_end_time( end_time );
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state_t s = this->state_;
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this->state = &s;
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// even on x86, using s.time in place of s_time was slower
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int16_t s_time = s.time;
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// registers
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uint16_t pc = r.pc;
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uint8_t a = r.a;
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uint8_t x = r.x;
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uint8_t y = r.y;
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uint16_t sp;
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SET_SP( r.sp );
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// status flags
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#define IS_NEG (nz & 0x8080)
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#define CALC_STATUS( out ) do {\
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out = status & (st_v | st_d | st_i);\
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out |= ((nz >> 8) | nz) & st_n;\
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out |= c >> 8 & st_c;\
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if ( !(nz & 0xFF) ) out |= st_z;\
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} while ( 0 )
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#define SET_STATUS( in ) do {\
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status = in & (st_v | st_d | st_i);\
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nz = in << 8;\
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c = nz;\
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nz |= ~in & st_z;\
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} while ( 0 )
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uint8_t status;
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uint16_t c; // carry set if (c & 0x100) != 0
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uint16_t nz; // Z set if (nz & 0xFF) == 0, N set if (nz & 0x8080) != 0
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{
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uint8_t temp = r.status;
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SET_STATUS( temp );
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}
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goto loop;
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dec_clock_loop:
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s_time--;
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loop:
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check( (unsigned) GET_SP() < 0x100 );
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check( (unsigned) pc < 0x10000 );
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check( (unsigned) a < 0x100 );
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check( (unsigned) x < 0x100 );
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check( (unsigned) y < 0x100 );
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check( -32768 <= s_time && s_time < 32767 );
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uint8_t const* instr = s.code_map [pc >> page_bits];
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uint8_t opcode;
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// TODO: eliminate this special case
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#if BLARGG_NONPORTABLE
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opcode = instr [pc];
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pc++;
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instr += pc;
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#else
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instr += PAGE_OFFSET( pc );
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opcode = *instr++;
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pc++;
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#endif
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static uint8_t const clock_table [256] =
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{// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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0,6,2,8,3,3,5,5,3,2,2,2,4,4,6,6,// 0
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3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 1
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6,6,2,8,3,3,5,5,4,2,2,2,4,4,6,6,// 2
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3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 3
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6,6,2,8,3,3,5,5,3,2,2,2,3,4,6,6,// 4
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3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 5
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6,6,2,8,3,3,5,5,4,2,2,2,5,4,6,6,// 6
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3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 7
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2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,// 8
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3,6,2,6,4,4,4,4,2,5,2,5,5,5,5,5,// 9
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2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,// A
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3,5,2,5,4,4,4,4,2,4,2,4,4,4,4,4,// B
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2,6,2,8,3,3,5,5,2,2,2,2,4,4,6,6,// C
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3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// D
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2,6,2,8,3,3,5,5,2,2,2,2,4,4,6,6,// E
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3,5,0,8,4,4,6,6,2,4,2,7,4,4,7,7 // F
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}; // 0x00 was 7 and 0xF2 was 2
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uint16_t data;
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#if !BLARGG_CPU_X86
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if ( s_time >= 0 )
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goto out_of_time;
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s_time += clock_table [opcode];
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data = *instr;
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switch ( opcode )
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{
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#else
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data = clock_table [opcode];
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if ( (s_time += data) >= 0 )
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goto possibly_out_of_time;
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almost_out_of_time:
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data = *instr;
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switch ( opcode )
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{
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possibly_out_of_time:
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if ( s_time < (int) data )
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goto almost_out_of_time;
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s_time -= data;
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goto out_of_time;
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#endif
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// Macros
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#define GET_MSB() (instr [1])
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#define ADD_PAGE() (pc++, data += 0x100 * GET_MSB())
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#define GET_ADDR() GET_LE16( instr )
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#define NO_PAGE_CROSSING( lsb )
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#define HANDLE_PAGE_CROSSING( lsb ) s_time += (lsb) >> 8;
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#define INC_DEC_XY( reg, n ) reg = uint8_t (nz = reg + n); goto loop;
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#define IND_Y( cross, out ) {\
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uint16_t temp = READ_LOW( data ) + y;\
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out = temp + 0x100 * READ_LOW( uint8_t (data + 1) );\
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cross( temp );\
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}
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#define IND_X( out ) {\
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uint16_t temp = data + x;\
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out = 0x100 * READ_LOW( uint8_t (temp + 1) ) + READ_LOW( uint8_t (temp) );\
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}
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#define ARITH_ADDR_MODES( op )\
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case op - 0x04: /* (ind,x) */\
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IND_X( data )\
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goto ptr##op;\
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case op + 0x0C: /* (ind),y */\
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IND_Y( HANDLE_PAGE_CROSSING, data )\
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goto ptr##op;\
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case op + 0x10: /* zp,X */\
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data = uint8_t (data + x);\
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case op + 0x00: /* zp */\
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data = READ_LOW( data );\
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goto imm##op;\
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case op + 0x14: /* abs,Y */\
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data += y;\
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goto ind##op;\
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case op + 0x18: /* abs,X */\
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data += x;\
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ind##op:\
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HANDLE_PAGE_CROSSING( data );\
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case op + 0x08: /* abs */\
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ADD_PAGE();\
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ptr##op:\
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FLUSH_TIME();\
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data = READ( data );\
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CACHE_TIME();\
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case op + 0x04: /* imm */\
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imm##op:
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// TODO: more efficient way to handle negative branch that wraps PC around
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#define BRANCH( cond )\
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{\
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int16_t offset = (int8_t) data;\
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uint16_t extra_clock = (++pc & 0xFF) + offset;\
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if ( !(cond) ) goto dec_clock_loop;\
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pc = uint16_t (pc + offset);\
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s_time += extra_clock >> 8 & 1;\
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goto loop;\
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}
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// Often-Used
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case 0xB5: // LDA zp,x
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a = nz = READ_LOW( uint8_t (data + x) );
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pc++;
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goto loop;
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case 0xA5: // LDA zp
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a = nz = READ_LOW( data );
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pc++;
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goto loop;
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case 0xD0: // BNE
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BRANCH( (uint8_t) nz );
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case 0x20: { // JSR
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uint16_t temp = pc + 1;
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pc = GET_ADDR();
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WRITE_LOW( 0x100 | (sp - 1), temp >> 8 );
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sp = (sp - 2) | 0x100;
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WRITE_LOW( sp, temp );
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goto loop;
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}
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case 0x4C: // JMP abs
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pc = GET_ADDR();
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goto loop;
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case 0xE8: // INX
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INC_DEC_XY( x, 1 )
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case 0x10: // BPL
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BRANCH( !IS_NEG )
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ARITH_ADDR_MODES( 0xC5 ) // CMP
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nz = a - data;
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pc++;
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c = ~nz;
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nz &= 0xFF;
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goto loop;
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case 0x30: // BMI
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BRANCH( IS_NEG )
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case 0xF0: // BEQ
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BRANCH( !(uint8_t) nz );
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case 0x95: // STA zp,x
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data = uint8_t (data + x);
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case 0x85: // STA zp
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pc++;
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WRITE_LOW( data, a );
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goto loop;
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case 0xC8: // INY
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INC_DEC_XY( y, 1 )
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case 0xA8: // TAY
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y = a;
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nz = a;
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goto loop;
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case 0x98: // TYA
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a = y;
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nz = y;
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goto loop;
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case 0xAD:{// LDA abs
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unsigned addr = GET_ADDR();
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pc += 2;
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READ_LIKELY_PPU( addr, nz );
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a = nz;
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goto loop;
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}
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case 0x60: // RTS
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pc = 1 + READ_LOW( sp );
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pc += 0x100 * READ_LOW( 0x100 | (sp - 0xFF) );
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sp = (sp - 0xFE) | 0x100;
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goto loop;
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{
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uint16_t addr;
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case 0x99: // STA abs,Y
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addr = y + GET_ADDR();
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pc += 2;
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if ( addr <= 0x7FF )
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{
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WRITE_LOW( addr, a );
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goto loop;
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}
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goto sta_ptr;
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case 0x8D: // STA abs
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addr = GET_ADDR();
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pc += 2;
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if ( addr <= 0x7FF )
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{
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WRITE_LOW( addr, a );
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goto loop;
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}
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goto sta_ptr;
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case 0x9D: // STA abs,X (slightly more common than STA abs)
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addr = x + GET_ADDR();
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pc += 2;
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if ( addr <= 0x7FF )
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{
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WRITE_LOW( addr, a );
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goto loop;
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}
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sta_ptr:
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FLUSH_TIME();
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WRITE( addr, a );
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CACHE_TIME();
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goto loop;
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case 0x91: // STA (ind),Y
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IND_Y( NO_PAGE_CROSSING, addr )
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pc++;
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goto sta_ptr;
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case 0x81: // STA (ind,X)
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IND_X( addr )
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pc++;
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goto sta_ptr;
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}
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case 0xA9: // LDA #imm
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pc++;
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a = data;
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nz = data;
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goto loop;
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// common read instructions
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{
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uint16_t addr;
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case 0xA1: // LDA (ind,X)
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IND_X( addr )
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pc++;
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goto a_nz_read_addr;
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case 0xB1:// LDA (ind),Y
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addr = READ_LOW( data ) + y;
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HANDLE_PAGE_CROSSING( addr );
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addr += 0x100 * READ_LOW( (uint8_t) (data + 1) );
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pc++;
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a = nz = READ_PROG( addr );
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if ( (addr ^ 0x8000) <= 0x9FFF )
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goto loop;
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goto a_nz_read_addr;
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case 0xB9: // LDA abs,Y
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HANDLE_PAGE_CROSSING( data + y );
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addr = GET_ADDR() + y;
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pc += 2;
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a = nz = READ_PROG( addr );
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if ( (addr ^ 0x8000) <= 0x9FFF )
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goto loop;
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goto a_nz_read_addr;
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case 0xBD: // LDA abs,X
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HANDLE_PAGE_CROSSING( data + x );
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addr = GET_ADDR() + x;
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pc += 2;
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a = nz = READ_PROG( addr );
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if ( (addr ^ 0x8000) <= 0x9FFF )
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goto loop;
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a_nz_read_addr:
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FLUSH_TIME();
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a = nz = READ( addr );
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CACHE_TIME();
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goto loop;
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}
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// Branch
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case 0x50: // BVC
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BRANCH( !(status & st_v) )
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case 0x70: // BVS
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BRANCH( status & st_v )
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case 0xB0: // BCS
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BRANCH( c & 0x100 )
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case 0x90: // BCC
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BRANCH( !(c & 0x100) )
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// Load/store
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case 0x94: // STY zp,x
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data = uint8_t (data + x);
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case 0x84: // STY zp
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pc++;
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WRITE_LOW( data, y );
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goto loop;
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case 0x96: // STX zp,y
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data = uint8_t (data + y);
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case 0x86: // STX zp
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pc++;
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WRITE_LOW( data, x );
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goto loop;
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case 0xB6: // LDX zp,y
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data = uint8_t (data + y);
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case 0xA6: // LDX zp
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data = READ_LOW( data );
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case 0xA2: // LDX #imm
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pc++;
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x = data;
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nz = data;
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goto loop;
|
|
|
|
case 0xB4: // LDY zp,x
|
|
data = uint8_t (data + x);
|
|
case 0xA4: // LDY zp
|
|
data = READ_LOW( data );
|
|
case 0xA0: // LDY #imm
|
|
pc++;
|
|
y = data;
|
|
nz = data;
|
|
goto loop;
|
|
|
|
case 0xBC: // LDY abs,X
|
|
data += x;
|
|
HANDLE_PAGE_CROSSING( data );
|
|
case 0xAC:{// LDY abs
|
|
unsigned addr = data + 0x100 * GET_MSB();
|
|
pc += 2;
|
|
FLUSH_TIME();
|
|
y = nz = READ( addr );
|
|
CACHE_TIME();
|
|
goto loop;
|
|
}
|
|
|
|
case 0xBE: // LDX abs,y
|
|
data += y;
|
|
HANDLE_PAGE_CROSSING( data );
|
|
case 0xAE:{// LDX abs
|
|
unsigned addr = data + 0x100 * GET_MSB();
|
|
pc += 2;
|
|
FLUSH_TIME();
|
|
x = nz = READ( addr );
|
|
CACHE_TIME();
|
|
goto loop;
|
|
}
|
|
|
|
{
|
|
uint8_t temp;
|
|
case 0x8C: // STY abs
|
|
temp = y;
|
|
goto store_abs;
|
|
|
|
case 0x8E: // STX abs
|
|
temp = x;
|
|
store_abs:
|
|
unsigned addr = GET_ADDR();
|
|
pc += 2;
|
|
if ( addr <= 0x7FF )
|
|
{
|
|
WRITE_LOW( addr, temp );
|
|
goto loop;
|
|
}
|
|
FLUSH_TIME();
|
|
WRITE( addr, temp );
|
|
CACHE_TIME();
|
|
goto loop;
|
|
}
|
|
|
|
// Compare
|
|
|
|
case 0xEC:{// CPX abs
|
|
unsigned addr = GET_ADDR();
|
|
pc++;
|
|
FLUSH_TIME();
|
|
data = READ( addr );
|
|
CACHE_TIME();
|
|
goto cpx_data;
|
|
}
|
|
|
|
case 0xE4: // CPX zp
|
|
data = READ_LOW( data );
|
|
case 0xE0: // CPX #imm
|
|
cpx_data:
|
|
nz = x - data;
|
|
pc++;
|
|
c = ~nz;
|
|
nz &= 0xFF;
|
|
goto loop;
|
|
|
|
case 0xCC:{// CPY abs
|
|
unsigned addr = GET_ADDR();
|
|
pc++;
|
|
FLUSH_TIME();
|
|
data = READ( addr );
|
|
CACHE_TIME();
|
|
goto cpy_data;
|
|
}
|
|
|
|
case 0xC4: // CPY zp
|
|
data = READ_LOW( data );
|
|
case 0xC0: // CPY #imm
|
|
cpy_data:
|
|
nz = y - data;
|
|
pc++;
|
|
c = ~nz;
|
|
nz &= 0xFF;
|
|
goto loop;
|
|
|
|
// Logical
|
|
|
|
ARITH_ADDR_MODES( 0x25 ) // AND
|
|
nz = (a &= data);
|
|
pc++;
|
|
goto loop;
|
|
|
|
ARITH_ADDR_MODES( 0x45 ) // EOR
|
|
nz = (a ^= data);
|
|
pc++;
|
|
goto loop;
|
|
|
|
ARITH_ADDR_MODES( 0x05 ) // ORA
|
|
nz = (a |= data);
|
|
pc++;
|
|
goto loop;
|
|
|
|
case 0x2C:{// BIT abs
|
|
unsigned addr = GET_ADDR();
|
|
pc += 2;
|
|
status &= ~st_v;
|
|
READ_LIKELY_PPU( addr, nz );
|
|
status |= nz & st_v;
|
|
if ( a & nz )
|
|
goto loop;
|
|
nz <<= 8; // result must be zero, even if N bit is set
|
|
goto loop;
|
|
}
|
|
|
|
case 0x24: // BIT zp
|
|
nz = READ_LOW( data );
|
|
pc++;
|
|
status &= ~st_v;
|
|
status |= nz & st_v;
|
|
if ( a & nz )
|
|
goto loop;
|
|
nz <<= 8; // result must be zero, even if N bit is set
|
|
goto loop;
|
|
|
|
// Add/subtract
|
|
|
|
ARITH_ADDR_MODES( 0xE5 ) // SBC
|
|
case 0xEB: // unofficial equivalent
|
|
data ^= 0xFF;
|
|
goto adc_imm;
|
|
|
|
ARITH_ADDR_MODES( 0x65 ) // ADC
|
|
adc_imm: {
|
|
int16_t carry = c >> 8 & 1;
|
|
int16_t ov = (a ^ 0x80) + carry + (int8_t) data; // sign-extend
|
|
status &= ~st_v;
|
|
status |= ov >> 2 & 0x40;
|
|
c = nz = a + data + carry;
|
|
pc++;
|
|
a = (uint8_t) nz;
|
|
goto loop;
|
|
}
|
|
|
|
// Shift/rotate
|
|
|
|
case 0x4A: // LSR A
|
|
c = 0;
|
|
case 0x6A: // ROR A
|
|
nz = c >> 1 & 0x80;
|
|
c = a << 8;
|
|
nz |= a >> 1;
|
|
a = nz;
|
|
goto loop;
|
|
|
|
case 0x0A: // ASL A
|
|
nz = a << 1;
|
|
c = nz;
|
|
a = (uint8_t) nz;
|
|
goto loop;
|
|
|
|
case 0x2A: { // ROL A
|
|
nz = a << 1;
|
|
int16_t temp = c >> 8 & 1;
|
|
c = nz;
|
|
nz |= temp;
|
|
a = (uint8_t) nz;
|
|
goto loop;
|
|
}
|
|
|
|
case 0x5E: // LSR abs,X
|
|
data += x;
|
|
case 0x4E: // LSR abs
|
|
c = 0;
|
|
case 0x6E: // ROR abs
|
|
ror_abs: {
|
|
ADD_PAGE();
|
|
FLUSH_TIME();
|
|
int temp = READ( data );
|
|
nz = (c >> 1 & 0x80) | (temp >> 1);
|
|
c = temp << 8;
|
|
goto rotate_common;
|
|
}
|
|
|
|
case 0x3E: // ROL abs,X
|
|
data += x;
|
|
goto rol_abs;
|
|
|
|
case 0x1E: // ASL abs,X
|
|
data += x;
|
|
case 0x0E: // ASL abs
|
|
c = 0;
|
|
case 0x2E: // ROL abs
|
|
rol_abs:
|
|
ADD_PAGE();
|
|
nz = c >> 8 & 1;
|
|
FLUSH_TIME();
|
|
nz |= (c = READ( data ) << 1);
|
|
rotate_common:
|
|
pc++;
|
|
WRITE( data, (uint8_t) nz );
|
|
CACHE_TIME();
|
|
goto loop;
|
|
|
|
case 0x7E: // ROR abs,X
|
|
data += x;
|
|
goto ror_abs;
|
|
|
|
case 0x76: // ROR zp,x
|
|
data = uint8_t (data + x);
|
|
goto ror_zp;
|
|
|
|
case 0x56: // LSR zp,x
|
|
data = uint8_t (data + x);
|
|
case 0x46: // LSR zp
|
|
c = 0;
|
|
case 0x66: // ROR zp
|
|
ror_zp: {
|
|
int temp = READ_LOW( data );
|
|
nz = (c >> 1 & 0x80) | (temp >> 1);
|
|
c = temp << 8;
|
|
goto write_nz_zp;
|
|
}
|
|
|
|
case 0x36: // ROL zp,x
|
|
data = uint8_t (data + x);
|
|
goto rol_zp;
|
|
|
|
case 0x16: // ASL zp,x
|
|
data = uint8_t (data + x);
|
|
case 0x06: // ASL zp
|
|
c = 0;
|
|
case 0x26: // ROL zp
|
|
rol_zp:
|
|
nz = c >> 8 & 1;
|
|
nz |= (c = READ_LOW( data ) << 1);
|
|
goto write_nz_zp;
|
|
|
|
// Increment/decrement
|
|
|
|
case 0xCA: // DEX
|
|
INC_DEC_XY( x, -1 )
|
|
|
|
case 0x88: // DEY
|
|
INC_DEC_XY( y, -1 )
|
|
|
|
case 0xF6: // INC zp,x
|
|
data = uint8_t (data + x);
|
|
case 0xE6: // INC zp
|
|
nz = 1;
|
|
goto add_nz_zp;
|
|
|
|
case 0xD6: // DEC zp,x
|
|
data = uint8_t (data + x);
|
|
case 0xC6: // DEC zp
|
|
nz = (uint16_t) -1;
|
|
add_nz_zp:
|
|
nz += READ_LOW( data );
|
|
write_nz_zp:
|
|
pc++;
|
|
WRITE_LOW( data, nz );
|
|
goto loop;
|
|
|
|
case 0xFE: // INC abs,x
|
|
data = x + GET_ADDR();
|
|
goto inc_ptr;
|
|
|
|
case 0xEE: // INC abs
|
|
data = GET_ADDR();
|
|
inc_ptr:
|
|
nz = 1;
|
|
goto inc_common;
|
|
|
|
case 0xDE: // DEC abs,x
|
|
data = x + GET_ADDR();
|
|
goto dec_ptr;
|
|
|
|
case 0xCE: // DEC abs
|
|
data = GET_ADDR();
|
|
dec_ptr:
|
|
nz = (uint16_t) -1;
|
|
inc_common:
|
|
FLUSH_TIME();
|
|
nz += READ( data );
|
|
pc += 2;
|
|
WRITE( data, (uint8_t) nz );
|
|
CACHE_TIME();
|
|
goto loop;
|
|
|
|
// Transfer
|
|
|
|
case 0xAA: // TAX
|
|
x = a;
|
|
nz = a;
|
|
goto loop;
|
|
|
|
case 0x8A: // TXA
|
|
a = x;
|
|
nz = x;
|
|
goto loop;
|
|
|
|
case 0x9A: // TXS
|
|
SET_SP( x ); // verified (no flag change)
|
|
goto loop;
|
|
|
|
case 0xBA: // TSX
|
|
x = nz = GET_SP();
|
|
goto loop;
|
|
|
|
// Stack
|
|
|
|
case 0x48: // PHA
|
|
PUSH( a ); // verified
|
|
goto loop;
|
|
|
|
case 0x68: // PLA
|
|
a = nz = READ_LOW( sp );
|
|
sp = (sp - 0xFF) | 0x100;
|
|
goto loop;
|
|
|
|
case 0x40:{// RTI
|
|
uint8_t temp = READ_LOW( sp );
|
|
pc = READ_LOW( 0x100 | (sp - 0xFF) );
|
|
pc |= READ_LOW( 0x100 | (sp - 0xFE) ) * 0x100;
|
|
sp = (sp - 0xFD) | 0x100;
|
|
data = status;
|
|
SET_STATUS( temp );
|
|
if ( !((data ^ status) & st_i) ) goto loop; // I flag didn't change
|
|
this->r.status = status; // update externally-visible I flag
|
|
blargg_long delta = s.base - irq_time_;
|
|
if ( delta <= 0 ) goto loop;
|
|
if ( status & st_i ) goto loop;
|
|
s_time += delta;
|
|
s.base = irq_time_;
|
|
goto loop;
|
|
}
|
|
|
|
case 0x28:{// PLP
|
|
uint8_t temp = READ_LOW( sp );
|
|
sp = (sp - 0xFF) | 0x100;
|
|
uint8_t changed = status ^ temp;
|
|
SET_STATUS( temp );
|
|
if ( !(changed & st_i) )
|
|
goto loop; // I flag didn't change
|
|
if ( status & st_i )
|
|
goto handle_sei;
|
|
goto handle_cli;
|
|
}
|
|
|
|
case 0x08: { // PHP
|
|
uint8_t temp;
|
|
CALC_STATUS( temp );
|
|
PUSH( temp | (st_b | st_r) );
|
|
goto loop;
|
|
}
|
|
|
|
case 0x6C:{// JMP (ind)
|
|
data = GET_ADDR();
|
|
check( unsigned (data - 0x2000) >= 0x4000 ); // ensure it's outside I/O space
|
|
uint8_t const* page = s.code_map [data >> page_bits];
|
|
pc = page [PAGE_OFFSET( data )];
|
|
data = (data & 0xFF00) | ((data + 1) & 0xFF);
|
|
pc |= page [PAGE_OFFSET( data )] << 8;
|
|
goto loop;
|
|
}
|
|
|
|
case 0x00: // BRK
|
|
goto handle_brk;
|
|
|
|
// Flags
|
|
|
|
case 0x38: // SEC
|
|
c = (uint16_t) ~0;
|
|
goto loop;
|
|
|
|
case 0x18: // CLC
|
|
c = 0;
|
|
goto loop;
|
|
|
|
case 0xB8: // CLV
|
|
status &= ~st_v;
|
|
goto loop;
|
|
|
|
case 0xD8: // CLD
|
|
status &= ~st_d;
|
|
goto loop;
|
|
|
|
case 0xF8: // SED
|
|
status |= st_d;
|
|
goto loop;
|
|
|
|
case 0x58: // CLI
|
|
if ( !(status & st_i) )
|
|
goto loop;
|
|
status &= ~st_i;
|
|
handle_cli: {
|
|
//debug_printf( "CLI at %d\n", TIME );
|
|
this->r.status = status; // update externally-visible I flag
|
|
blargg_long delta = s.base - irq_time_;
|
|
if ( delta <= 0 )
|
|
{
|
|
if ( TIME < irq_time_ )
|
|
goto loop;
|
|
goto delayed_cli;
|
|
}
|
|
s.base = irq_time_;
|
|
s_time += delta;
|
|
if ( s_time < 0 )
|
|
goto loop;
|
|
|
|
if ( delta >= s_time + 1 )
|
|
{
|
|
s.base += s_time + 1;
|
|
s_time = -1;
|
|
goto loop;
|
|
}
|
|
|
|
// TODO: implement
|
|
delayed_cli:
|
|
debug_printf( "Delayed CLI not emulated\n" );
|
|
goto loop;
|
|
}
|
|
|
|
case 0x78: // SEI
|
|
if ( status & st_i )
|
|
goto loop;
|
|
status |= st_i;
|
|
handle_sei: {
|
|
this->r.status = status; // update externally-visible I flag
|
|
blargg_long delta = s.base - end_time_;
|
|
s.base = end_time_;
|
|
s_time += delta;
|
|
if ( s_time < 0 )
|
|
goto loop;
|
|
|
|
debug_printf( "Delayed SEI not emulated\n" );
|
|
goto loop;
|
|
}
|
|
|
|
// Unofficial
|
|
|
|
// SKW - Skip word
|
|
case 0x1C: case 0x3C: case 0x5C: case 0x7C: case 0xDC: case 0xFC:
|
|
HANDLE_PAGE_CROSSING( data + x );
|
|
case 0x0C:
|
|
pc++;
|
|
// SKB - Skip byte
|
|
case 0x74: case 0x04: case 0x14: case 0x34: case 0x44: case 0x54: case 0x64:
|
|
case 0x80: case 0x82: case 0x89: case 0xC2: case 0xD4: case 0xE2: case 0xF4:
|
|
pc++;
|
|
goto loop;
|
|
|
|
// NOP
|
|
case 0xEA: case 0x1A: case 0x3A: case 0x5A: case 0x7A: case 0xDA: case 0xFA:
|
|
goto loop;
|
|
|
|
case bad_opcode: // HLT
|
|
pc--;
|
|
case 0x02: case 0x12: case 0x22: case 0x32: case 0x42: case 0x52:
|
|
case 0x62: case 0x72: case 0x92: case 0xB2: case 0xD2:
|
|
goto stop;
|
|
|
|
// Unimplemented
|
|
|
|
case 0xFF: // force 256-entry jump table for optimization purposes
|
|
c |= 1;
|
|
default:
|
|
check( (unsigned) opcode <= 0xFF );
|
|
// skip over proper number of bytes
|
|
static unsigned char const illop_lens [8] = {
|
|
0x40, 0x40, 0x40, 0x80, 0x40, 0x40, 0x80, 0xA0
|
|
};
|
|
uint8_t opcode = instr [-1];
|
|
int16_t len = illop_lens [opcode >> 2 & 7] >> (opcode << 1 & 6) & 3;
|
|
if ( opcode == 0x9C )
|
|
len = 2;
|
|
pc += len;
|
|
error_count_++;
|
|
|
|
if ( (opcode >> 4) == 0x0B )
|
|
{
|
|
if ( opcode == 0xB3 )
|
|
data = READ_LOW( data );
|
|
if ( opcode != 0xB7 )
|
|
HANDLE_PAGE_CROSSING( data + y );
|
|
}
|
|
goto loop;
|
|
}
|
|
assert( false );
|
|
|
|
int result_;
|
|
handle_brk:
|
|
pc++;
|
|
result_ = 4;
|
|
|
|
interrupt:
|
|
{
|
|
s_time += 7;
|
|
|
|
WRITE_LOW( 0x100 | (sp - 1), pc >> 8 );
|
|
WRITE_LOW( 0x100 | (sp - 2), pc );
|
|
pc = GET_LE16( &READ_PROG( 0xFFFA ) + result_ );
|
|
|
|
sp = (sp - 3) | 0x100;
|
|
uint8_t temp;
|
|
CALC_STATUS( temp );
|
|
temp |= st_r;
|
|
if ( result_ )
|
|
temp |= st_b; // TODO: incorrectly sets B flag for IRQ
|
|
WRITE_LOW( sp, temp );
|
|
|
|
this->r.status = status |= st_i;
|
|
blargg_long delta = s.base - end_time_;
|
|
if ( delta >= 0 ) goto loop;
|
|
s_time += delta;
|
|
s.base = end_time_;
|
|
goto loop;
|
|
}
|
|
|
|
out_of_time:
|
|
pc--;
|
|
FLUSH_TIME();
|
|
CPU_DONE( this, TIME, result_ );
|
|
CACHE_TIME();
|
|
if ( result_ >= 0 )
|
|
goto interrupt;
|
|
if ( s_time < 0 )
|
|
goto loop;
|
|
|
|
stop:
|
|
|
|
s.time = s_time;
|
|
|
|
r.pc = pc;
|
|
r.sp = GET_SP();
|
|
r.a = a;
|
|
r.x = x;
|
|
r.y = y;
|
|
|
|
{
|
|
uint8_t temp;
|
|
CALC_STATUS( temp );
|
|
r.status = temp;
|
|
}
|
|
|
|
this->state_ = s;
|
|
this->state = &this->state_;
|
|
|
|
return s_time < 0;
|
|
}
|
|
|