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Diffstat (limited to 'plugins/gme/game-music-emu-0.6.0/gme/Nes_Cpu.cpp')
-rw-r--r--plugins/gme/game-music-emu-0.6.0/gme/Nes_Cpu.cpp1084
1 files changed, 1084 insertions, 0 deletions
diff --git a/plugins/gme/game-music-emu-0.6.0/gme/Nes_Cpu.cpp b/plugins/gme/game-music-emu-0.6.0/gme/Nes_Cpu.cpp
new file mode 100644
index 00000000..864e0dde
--- /dev/null
+++ b/plugins/gme/game-music-emu-0.6.0/gme/Nes_Cpu.cpp
@@ -0,0 +1,1084 @@
+// Game_Music_Emu 0.5.5. http://www.slack.net/~ant/
+
+#include "Nes_Cpu.h"
+
+#include "blargg_endian.h"
+#include <limits.h>
+
+#define BLARGG_CPU_X86 1
+
+/* Copyright (C) 2003-2006 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 */
+
+#ifdef BLARGG_ENABLE_OPTIMIZER
+ #include BLARGG_ENABLE_OPTIMIZER
+#endif
+
+#define FLUSH_TIME() (void) (s.time = s_time)
+#define CACHE_TIME() (void) (s_time = s.time)
+
+#include "nes_cpu_io.h"
+
+#include "blargg_source.h"
+
+#ifndef CPU_DONE
+ #define CPU_DONE( cpu, time, result_out ) { result_out = -1; }
+#endif
+
+#ifndef CPU_READ_PPU
+ #define CPU_READ_PPU( cpu, addr, out, time )\
+ {\
+ FLUSH_TIME();\
+ out = CPU_READ( cpu, addr, time );\
+ CACHE_TIME();\
+ }
+#endif
+
+#if BLARGG_NONPORTABLE
+ #define PAGE_OFFSET( addr ) (addr)
+#else
+ #define PAGE_OFFSET( addr ) ((addr) & (page_size - 1))
+#endif
+
+inline void Nes_Cpu::set_code_page( int i, void const* p )
+{
+ state->code_map [i] = (uint8_t const*) p - PAGE_OFFSET( i * page_size );
+}
+
+int const st_n = 0x80;
+int const st_v = 0x40;
+int const st_r = 0x20;
+int const st_b = 0x10;
+int const st_d = 0x08;
+int const st_i = 0x04;
+int const st_z = 0x02;
+int const st_c = 0x01;
+
+void Nes_Cpu::reset( void const* unmapped_page )
+{
+ check( state == &state_ );
+ state = &state_;
+ r.status = st_i;
+ r.sp = 0xFF;
+ r.pc = 0;
+ r.a = 0;
+ r.x = 0;
+ r.y = 0;
+ state_.time = 0;
+ state_.base = 0;
+ irq_time_ = future_nes_time;
+ end_time_ = future_nes_time;
+ error_count_ = 0;
+
+ assert( page_size == 0x800 ); // assumes this
+ set_code_page( page_count, unmapped_page );
+ map_code( 0x2000, 0xE000, unmapped_page, true );
+ map_code( 0x0000, 0x2000, low_mem, true );
+
+ blargg_verify_byte_order();
+}
+
+void Nes_Cpu::map_code( nes_addr_t start, unsigned size, void const* data, bool mirror )
+{
+ // address range must begin and end on page boundaries
+ require( start % page_size == 0 );
+ require( size % page_size == 0 );
+ require( start + size <= 0x10000 );
+
+ unsigned page = start / page_size;
+ for ( unsigned n = size / page_size; n; --n )
+ {
+ set_code_page( page++, data );
+ if ( !mirror )
+ data = (char const*) data + page_size;
+ }
+}
+
+#define TIME (s_time + s.base)
+#define READ_LIKELY_PPU( addr, out ) {CPU_READ_PPU( this, (addr), out, TIME );}
+#define READ( addr ) CPU_READ( this, (addr), TIME )
+#define WRITE( addr, data ) {CPU_WRITE( this, (addr), (data), TIME );}
+#define READ_LOW( addr ) (low_mem [int (addr)])
+#define WRITE_LOW( addr, data ) (void) (READ_LOW( addr ) = (data))
+#define READ_PROG( addr ) (s.code_map [(addr) >> page_bits] [PAGE_OFFSET( addr )])
+
+#define SET_SP( v ) (sp = ((v) + 1) | 0x100)
+#define GET_SP() ((sp - 1) & 0xFF)
+#define PUSH( v ) ((sp = (sp - 1) | 0x100), WRITE_LOW( sp, v ))
+
+// even on x86, using short and unsigned char was slower
+typedef int fint16;
+typedef unsigned fuint16;
+typedef unsigned fuint8;
+
+bool Nes_Cpu::run( nes_time_t end_time )
+{
+ set_end_time( end_time );
+ state_t s = this->state_;
+ this->state = &s;
+ // even on x86, using s.time in place of s_time was slower
+ fint16 s_time = s.time;
+
+ // registers
+ fuint16 pc = r.pc;
+ fuint8 a = r.a;
+ fuint8 x = r.x;
+ fuint8 y = r.y;
+ fuint16 sp;
+ SET_SP( r.sp );
+
+ // status flags
+ #define IS_NEG (nz & 0x8080)
+
+ #define CALC_STATUS( out ) do {\
+ out = status & (st_v | st_d | st_i);\
+ out |= ((nz >> 8) | nz) & st_n;\
+ out |= c >> 8 & st_c;\
+ if ( !(nz & 0xFF) ) out |= st_z;\
+ } while ( 0 )
+
+ #define SET_STATUS( in ) do {\
+ status = in & (st_v | st_d | st_i);\
+ nz = in << 8;\
+ c = nz;\
+ nz |= ~in & st_z;\
+ } while ( 0 )
+
+ fuint8 status;
+ fuint16 c; // carry set if (c & 0x100) != 0
+ fuint16 nz; // Z set if (nz & 0xFF) == 0, N set if (nz & 0x8080) != 0
+ {
+ fuint8 temp = r.status;
+ SET_STATUS( temp );
+ }
+
+ goto loop;
+dec_clock_loop:
+ s_time--;
+loop:
+
+ check( (unsigned) GET_SP() < 0x100 );
+ check( (unsigned) pc < 0x10000 );
+ check( (unsigned) a < 0x100 );
+ check( (unsigned) x < 0x100 );
+ check( (unsigned) y < 0x100 );
+ check( -32768 <= s_time && s_time < 32767 );
+
+ uint8_t const* instr = s.code_map [pc >> page_bits];
+ fuint8 opcode;
+
+ // TODO: eliminate this special case
+ #if BLARGG_NONPORTABLE
+ opcode = instr [pc];
+ pc++;
+ instr += pc;
+ #else
+ instr += PAGE_OFFSET( pc );
+ opcode = *instr++;
+ pc++;
+ #endif
+
+ static uint8_t const clock_table [256] =
+ {// 0 1 2 3 4 5 6 7 8 9 A B C D E F
+ 0,6,2,8,3,3,5,5,3,2,2,2,4,4,6,6,// 0
+ 3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 1
+ 6,6,2,8,3,3,5,5,4,2,2,2,4,4,6,6,// 2
+ 3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 3
+ 6,6,2,8,3,3,5,5,3,2,2,2,3,4,6,6,// 4
+ 3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 5
+ 6,6,2,8,3,3,5,5,4,2,2,2,5,4,6,6,// 6
+ 3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 7
+ 2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,// 8
+ 3,6,2,6,4,4,4,4,2,5,2,5,5,5,5,5,// 9
+ 2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,// A
+ 3,5,2,5,4,4,4,4,2,4,2,4,4,4,4,4,// B
+ 2,6,2,8,3,3,5,5,2,2,2,2,4,4,6,6,// C
+ 3,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// D
+ 2,6,2,8,3,3,5,5,2,2,2,2,4,4,6,6,// E
+ 3,5,0,8,4,4,6,6,2,4,2,7,4,4,7,7 // F
+ }; // 0x00 was 7 and 0xF2 was 2
+
+ fuint16 data;
+
+#if !BLARGG_CPU_X86
+ if ( s_time >= 0 )
+ goto out_of_time;
+ s_time += clock_table [opcode];
+
+ data = *instr;
+
+ switch ( opcode )
+ {
+#else
+
+ data = clock_table [opcode];
+ if ( (s_time += data) >= 0 )
+ goto possibly_out_of_time;
+almost_out_of_time:
+
+ data = *instr;
+
+ switch ( opcode )
+ {
+possibly_out_of_time:
+ if ( s_time < (int) data )
+ goto almost_out_of_time;
+ s_time -= data;
+ goto out_of_time;
+#endif
+
+// Macros
+
+#define GET_MSB() (instr [1])
+#define ADD_PAGE() (pc++, data += 0x100 * GET_MSB())
+#define GET_ADDR() GET_LE16( instr )
+
+#define NO_PAGE_CROSSING( lsb )
+#define HANDLE_PAGE_CROSSING( lsb ) s_time += (lsb) >> 8;
+
+#define INC_DEC_XY( reg, n ) reg = uint8_t (nz = reg + n); goto loop;
+
+#define IND_Y( cross, out ) {\
+ fuint16 temp = READ_LOW( data ) + y;\
+ out = temp + 0x100 * READ_LOW( uint8_t (data + 1) );\
+ cross( temp );\
+ }
+
+#define IND_X( out ) {\
+ fuint16 temp = data + x;\
+ out = 0x100 * READ_LOW( uint8_t (temp + 1) ) + READ_LOW( uint8_t (temp) );\
+ }
+
+#define ARITH_ADDR_MODES( op )\
+case op - 0x04: /* (ind,x) */\
+ IND_X( data )\
+ goto ptr##op;\
+case op + 0x0C: /* (ind),y */\
+ IND_Y( HANDLE_PAGE_CROSSING, data )\
+ goto ptr##op;\
+case op + 0x10: /* zp,X */\
+ data = uint8_t (data + x);\
+case op + 0x00: /* zp */\
+ data = READ_LOW( data );\
+ goto imm##op;\
+case op + 0x14: /* abs,Y */\
+ data += y;\
+ goto ind##op;\
+case op + 0x18: /* abs,X */\
+ data += x;\
+ind##op:\
+ HANDLE_PAGE_CROSSING( data );\
+case op + 0x08: /* abs */\
+ ADD_PAGE();\
+ptr##op:\
+ FLUSH_TIME();\
+ data = READ( data );\
+ CACHE_TIME();\
+case op + 0x04: /* imm */\
+imm##op:
+
+// TODO: more efficient way to handle negative branch that wraps PC around
+#define BRANCH( cond )\
+{\
+ fint16 offset = (BOOST::int8_t) data;\
+ fuint16 extra_clock = (++pc & 0xFF) + offset;\
+ if ( !(cond) ) goto dec_clock_loop;\
+ pc = BOOST::uint16_t (pc + offset);\
+ s_time += extra_clock >> 8 & 1;\
+ goto loop;\
+}
+
+// Often-Used
+
+ case 0xB5: // LDA zp,x
+ a = nz = READ_LOW( uint8_t (data + x) );
+ pc++;
+ goto loop;
+
+ case 0xA5: // LDA zp
+ a = nz = READ_LOW( data );
+ pc++;
+ goto loop;
+
+ case 0xD0: // BNE
+ BRANCH( (uint8_t) nz );
+
+ case 0x20: { // JSR
+ fuint16 temp = pc + 1;
+ pc = GET_ADDR();
+ WRITE_LOW( 0x100 | (sp - 1), temp >> 8 );
+ sp = (sp - 2) | 0x100;
+ WRITE_LOW( sp, temp );
+ goto loop;
+ }
+
+ case 0x4C: // JMP abs
+ pc = GET_ADDR();
+ goto loop;
+
+ case 0xE8: // INX
+ INC_DEC_XY( x, 1 )
+
+ case 0x10: // BPL
+ BRANCH( !IS_NEG )
+
+ ARITH_ADDR_MODES( 0xC5 ) // CMP
+ nz = a - data;
+ pc++;
+ c = ~nz;
+ nz &= 0xFF;
+ goto loop;
+
+ case 0x30: // BMI
+ BRANCH( IS_NEG )
+
+ case 0xF0: // BEQ
+ BRANCH( !(uint8_t) nz );
+
+ case 0x95: // STA zp,x
+ data = uint8_t (data + x);
+ case 0x85: // STA zp
+ pc++;
+ WRITE_LOW( data, a );
+ goto loop;
+
+ case 0xC8: // INY
+ INC_DEC_XY( y, 1 )
+
+ case 0xA8: // TAY
+ y = a;
+ nz = a;
+ goto loop;
+
+ case 0x98: // TYA
+ a = y;
+ nz = y;
+ goto loop;
+
+ case 0xAD:{// LDA abs
+ unsigned addr = GET_ADDR();
+ pc += 2;
+ READ_LIKELY_PPU( addr, nz );
+ a = nz;
+ goto loop;
+ }
+
+ case 0x60: // RTS
+ pc = 1 + READ_LOW( sp );
+ pc += 0x100 * READ_LOW( 0x100 | (sp - 0xFF) );
+ sp = (sp - 0xFE) | 0x100;
+ goto loop;
+
+ {
+ fuint16 addr;
+
+ case 0x99: // STA abs,Y
+ addr = y + GET_ADDR();
+ pc += 2;
+ if ( addr <= 0x7FF )
+ {
+ WRITE_LOW( addr, a );
+ goto loop;
+ }
+ goto sta_ptr;
+
+ case 0x8D: // STA abs
+ addr = GET_ADDR();
+ pc += 2;
+ if ( addr <= 0x7FF )
+ {
+ WRITE_LOW( addr, a );
+ goto loop;
+ }
+ goto sta_ptr;
+
+ case 0x9D: // STA abs,X (slightly more common than STA abs)
+ addr = x + GET_ADDR();
+ pc += 2;
+ if ( addr <= 0x7FF )
+ {
+ WRITE_LOW( addr, a );
+ goto loop;
+ }
+ sta_ptr:
+ FLUSH_TIME();
+ WRITE( addr, a );
+ CACHE_TIME();
+ goto loop;
+
+ case 0x91: // STA (ind),Y
+ IND_Y( NO_PAGE_CROSSING, addr )
+ pc++;
+ goto sta_ptr;
+
+ case 0x81: // STA (ind,X)
+ IND_X( addr )
+ pc++;
+ goto sta_ptr;
+
+ }
+
+ case 0xA9: // LDA #imm
+ pc++;
+ a = data;
+ nz = data;
+ goto loop;
+
+ // common read instructions
+ {
+ fuint16 addr;
+
+ case 0xA1: // LDA (ind,X)
+ IND_X( addr )
+ pc++;
+ goto a_nz_read_addr;
+
+ case 0xB1:// LDA (ind),Y
+ addr = READ_LOW( data ) + y;
+ HANDLE_PAGE_CROSSING( addr );
+ addr += 0x100 * READ_LOW( (uint8_t) (data + 1) );
+ pc++;
+ a = nz = READ_PROG( addr );
+ if ( (addr ^ 0x8000) <= 0x9FFF )
+ goto loop;
+ goto a_nz_read_addr;
+
+ case 0xB9: // LDA abs,Y
+ HANDLE_PAGE_CROSSING( data + y );
+ addr = GET_ADDR() + y;
+ pc += 2;
+ a = nz = READ_PROG( addr );
+ if ( (addr ^ 0x8000) <= 0x9FFF )
+ goto loop;
+ goto a_nz_read_addr;
+
+ case 0xBD: // LDA abs,X
+ HANDLE_PAGE_CROSSING( data + x );
+ addr = GET_ADDR() + x;
+ pc += 2;
+ a = nz = READ_PROG( addr );
+ if ( (addr ^ 0x8000) <= 0x9FFF )
+ goto loop;
+ a_nz_read_addr:
+ FLUSH_TIME();
+ a = nz = READ( addr );
+ CACHE_TIME();
+ goto loop;
+
+ }
+
+// Branch
+
+ case 0x50: // BVC
+ BRANCH( !(status & st_v) )
+
+ case 0x70: // BVS
+ BRANCH( status & st_v )
+
+ case 0xB0: // BCS
+ BRANCH( c & 0x100 )
+
+ case 0x90: // BCC
+ BRANCH( !(c & 0x100) )
+
+// Load/store
+
+ case 0x94: // STY zp,x
+ data = uint8_t (data + x);
+ case 0x84: // STY zp
+ pc++;
+ WRITE_LOW( data, y );
+ goto loop;
+
+ case 0x96: // STX zp,y
+ data = uint8_t (data + y);
+ case 0x86: // STX zp
+ pc++;
+ WRITE_LOW( data, x );
+ goto loop;
+
+ case 0xB6: // LDX zp,y
+ data = uint8_t (data + y);
+ case 0xA6: // LDX zp
+ data = READ_LOW( data );
+ case 0xA2: // LDX #imm
+ pc++;
+ x = data;
+ nz = data;
+ 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;
+ }
+
+ {
+ fuint8 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: {
+ fint16 carry = c >> 8 & 1;
+ fint16 ov = (a ^ 0x80) + carry + (BOOST::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;
+ fint16 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 = (unsigned) -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 = (unsigned) -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
+ fuint8 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
+ fuint8 temp = READ_LOW( sp );
+ sp = (sp - 0xFF) | 0x100;
+ fuint8 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
+ fuint8 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 = (unsigned) ~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--;
+ if ( pc > 0xFFFF )
+ {
+ // handle wrap-around (assumes caller has put page of HLT at 0x10000)
+ pc &= 0xFFFF;
+ goto loop;
+ }
+ 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
+ };
+ fuint8 opcode = instr [-1];
+ fint16 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;
+ fuint8 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;
+
+ {
+ fuint8 temp;
+ CALC_STATUS( temp );
+ r.status = temp;
+ }
+
+ this->state_ = s;
+ this->state = &this->state_;
+
+ return s_time < 0;
+}
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-03 21:57:19 +0000