diff options
Diffstat (limited to 'apps/codecs/libgme/nes_cpu_run.h')
| -rw-r--r-- | apps/codecs/libgme/nes_cpu_run.h | 1122 |
1 files changed, 0 insertions, 1122 deletions
diff --git a/apps/codecs/libgme/nes_cpu_run.h b/apps/codecs/libgme/nes_cpu_run.h deleted file mode 100644 index fd1fea9659..0000000000 --- a/apps/codecs/libgme/nes_cpu_run.h +++ /dev/null @@ -1,1122 +0,0 @@ -// NES 6502 cpu emulator run function - -#if 0 -/* Define these macros in the source file before #including this file. -- Parameters might be expressions, so they are best evaluated only once, -though they NEVER have side-effects, so multiple evaluation is OK. -- Output parameters might be a multiple-assignment expression like "a=x", -so they must NOT be parenthesized. -- Except where noted, time() and related functions will NOT work -correctly inside a macro. TIME() is always correct, and FLUSH_TIME() and -CACHE_TIME() allow the time changing functions to work. -- Macros "returning" void may use a {} statement block. */ - - // 0 <= addr <= 0xFFFF + page_size - // time functions can be used - int READ_MEM( addr_t ); - void WRITE_MEM( addr_t, int data ); - // 0 <= READ_MEM() <= 0xFF - - // 0 <= addr <= 0x1FF - int READ_LOW( addr_t ); - void WRITE_LOW( addr_t, int data ); - // 0 <= READ_LOW() <= 0xFF - - // Often-used instructions attempt these before using a normal memory access. - // Optional; defaults to READ_MEM() and WRITE_MEM() - bool CAN_READ_FAST( addr_t ); // if true, uses result of READ_FAST - void READ_FAST( addr_t, int& out ); // ALWAYS called BEFORE CAN_READ_FAST - bool CAN_WRITE_FAST( addr_t ); // if true, uses WRITE_FAST instead of WRITE_MEM - void WRITE_FAST( addr_t, int data ); - - // Used by instructions most often used to access the NES PPU (LDA abs and BIT abs). - // Optional; defaults to READ_MEM. - void READ_PPU( addr_t, int& out ); - // 0 <= out <= 0xFF - -// The following can be used within macros: - - // Current time - time_t TIME(); - - // Allows use of time functions - void FLUSH_TIME(); - - // Must be used before end of macro if FLUSH_TIME() was used earlier - void CACHE_TIME(); - -// Configuration (optional; commented behavior if defined) - - // Emulates dummy reads for indexed instructions - #define NES_CPU_DUMMY_READS 1 - - // Optimizes as if map_code( 0, 0x10000 + cpu_padding, FLAT_MEM ) is always in effect - #define FLAT_MEM my_mem_array - - // Expanded just before beginning of code, to help debugger - #define CPU_BEGIN void my_run_cpu() { - -#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 */ - -// Allows MWCW debugger to step through code properly -#ifdef CPU_BEGIN - CPU_BEGIN -#endif - -// Time -#define TIME() (s_time + s.base) -#define FLUSH_TIME() {s.time = s_time - time_offset;} -#define CACHE_TIME() {s_time = s.time + time_offset;} - -// Defaults -#ifndef CAN_WRITE_FAST - #define CAN_WRITE_FAST( addr ) 0 - #define WRITE_FAST( addr, data ) -#endif - -#ifndef CAN_READ_FAST - #define CAN_READ_FAST( addr ) 0 - #define READ_FAST( addr, out ) -#endif - -#ifndef READ_PPU - #define READ_PPU( addr, out )\ - {\ - FLUSH_TIME();\ - out = READ_MEM( addr );\ - CACHE_TIME();\ - } -#endif - -#define READ_STACK READ_LOW -#define WRITE_STACK WRITE_LOW - -// Dummy reads -#ifdef NES_CPU_DUMMY_READS - // TODO: optimize time handling - #define DUMMY_READ( addr, idx ) \ - if ( (addr & 0xFF) < idx )\ - {\ - int const time_offset = 1;\ - FLUSH_TIME();\ - READ_MEM( (addr - 0x100) );\ - CACHE_TIME();\ - } -#else - #define DUMMY_READ( addr, idx ) -#endif - -// Code -#ifdef FLAT_MEM - #define CODE_PAGE( addr ) (FLAT_MEM) - #define CODE_OFFSET( addr ) (addr) -#else - #define CODE_PAGE( addr ) (s.code_map [NES_CPU_PAGE( addr )]) - #define CODE_OFFSET( addr ) NES_CPU_OFFSET( addr ) -#endif -#define READ_CODE( addr ) (CODE_PAGE( addr ) [CODE_OFFSET( addr )]) - -// Stack -#define SET_SP( v ) (sp = ((v) + 1) | 0x100) -#define GET_SP() ((sp - 1) & 0xFF) -#define SP( o ) ((sp + (o - (o>0)*0x100)) | 0x100) - -// Truncation -#define BYTE( n ) ((uint8_t ) (n)) /* (unsigned) n & 0xFF */ -#define SBYTE( n ) ((int8_t ) (n)) /* (BYTE( n ) ^ 0x80) - 0x80 */ -#define WORD( n ) ((uint16_t) (n)) /* (unsigned) n & 0xFFFF */ - -// Flags with hex value for clarity when used as mask. -// Stored in indicated variable during emulation. -int const n80 = 0x80; // nz -int const v40 = 0x40; // flags -int const r20 = 0x20; -int const b10 = 0x10; -int const d08 = 0x08; // flags -int const i04 = 0x04; // flags -int const z02 = 0x02; // nz -int const c01 = 0x01; // c - -#define IS_NEG (nz & 0x8080) - -#define GET_FLAGS( out ) \ -{\ - out = flags & (v40 | d08 | i04);\ - out += ((nz >> 8) | nz) & n80;\ - out += c >> 8 & c01;\ - if ( !BYTE( nz ) )\ - out += z02;\ -} - -#define SET_FLAGS( in ) \ -{\ - flags = in & (v40 | d08 | i04);\ - c = nz = in << 8;\ - nz += ~in & z02;\ -} - -{ - int const time_offset = 0; - - // Local state - struct cpu_state_t s; - #ifdef FLAT_MEM - s.base = cpu->cpu_state_.base; - #else - s = cpu->cpu_state_; - #endif - cpu->cpu_state = &s; - int s_time = cpu->cpu_state_.time; // helps even on x86 - - // Registers - int pc = cpu->r.pc; - int a = cpu->r.a; - int x = cpu->r.x; - int y = cpu->r.y; - int sp; - SET_SP( cpu->r.sp ); - - // Flags - int flags; - int c; // carry set if (c & 0x100) != 0 - int nz; // Z set if (nz & 0xFF) == 0, N set if (nz & 0x8080) != 0 - { - int temp = cpu->r.flags; - SET_FLAGS( temp ); - } - -loop: - - // Check all values - check( (unsigned) sp - 0x100 < 0x100 ); - check( (unsigned) pc < 0x10000 ); - check( (unsigned) a < 0x100 ); - check( (unsigned) x < 0x100 ); - check( (unsigned) y < 0x100 ); - - // Read instruction - byte const* instr = CODE_PAGE( pc ); - int opcode; - - if ( CODE_OFFSET(~0) == ~0 ) - { - opcode = instr [pc]; - pc++; - instr += pc; - } - else - { - instr += CODE_OFFSET( pc ); - opcode = *instr++; - pc++; - } - - // local to function in case it helps optimizer - static byte 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 - 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 1 - 6,6,0,8,3,3,5,5,4,2,2,2,4,4,6,6,// 2 - 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 3 - 6,6,2,8,3,3,5,5,3,2,2,2,3,4,6,6,// 4 - 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 5 - 6,6,2,8,3,3,5,5,4,2,2,2,5,4,6,6,// 6 - 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// 7 - 2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,// 8 - 2,6,2,6,4,4,4,4,2,5,2,5,5,5,5,5,// 9 - 2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,// A - 2,5,2,5,4,4,4,4,2,4,2,4,4,4,4,4,// B - 2,6,2,8,3,3,5,5,2,2,2,2,4,4,6,6,// C - 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7,// D - 2,6,2,8,3,3,5,5,2,2,2,2,4,4,6,6,// E - 2,5,2,8,4,4,6,6,2,4,2,7,4,4,7,7 // F - }; // 0x00 was 7 and 0x22 was 2 - - // Update time - if ( s_time >= 0 ) - goto out_of_time; - - #ifdef CPU_INSTR_HOOK - { CPU_INSTR_HOOK( (pc-1), (&instr [-1]), a, x, y, GET_SP(), TIME() ); } - #endif - - s_time += clock_table [opcode]; - - int data; - data = *instr; - - switch ( opcode ) - { - -// Macros - -#define GET_MSB() (instr [1]) -#define ADD_PAGE( out ) (pc++, out = data + 0x100 * GET_MSB()) -#define GET_ADDR() GET_LE16( instr ) - -#define PAGE_PENALTY( lsb ) s_time += (lsb) >> 8; - -#define INC_DEC( reg, n ) reg = BYTE( nz = reg + n ); goto loop; - -#define IND_Y( cross, out ) {\ - int temp = READ_LOW( data ) + y;\ - out = temp + 0x100 * READ_LOW( BYTE( data + 1 ) );\ - cross( temp );\ - } - -#define IND_X( out ) {\ - int temp = data + x;\ - out = 0x100 * READ_LOW( BYTE( temp + 1 ) ) + READ_LOW( BYTE( temp ) );\ - } - -#define ARITH_ADDR_MODES( op )\ -case op - 0x04: /* (ind,x) */\ - IND_X( data )\ - goto ptr##op;\ -case op + 0x0C: /* (ind),y */\ - IND_Y( PAGE_PENALTY, data )\ - goto ptr##op;\ -case op + 0x10: /* zp,X */\ - data = BYTE( 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:\ - PAGE_PENALTY( data );\ -case op + 0x08: /* abs */\ - ADD_PAGE( data );\ -ptr##op:\ - FLUSH_TIME();\ - data = READ_MEM( data );\ - CACHE_TIME();\ -case op + 0x04: /* imm */\ -imm##op: - -// TODO: more efficient way to handle negative branch that wraps PC around -#define BRANCH( cond )\ -{\ - ++pc;\ - if ( !(cond) ) goto loop;\ - s_time++;\ - int offset = SBYTE( data );\ - s_time += (BYTE(pc) + offset) >> 8 & 1;\ - pc = WORD( pc + offset );\ - goto loop;\ -} - -// Often-Used - - case 0xB5: // LDA zp,x - a = nz = READ_LOW( BYTE( data + x ) ); - pc++; - goto loop; - - case 0xA5: // LDA zp - a = nz = READ_LOW( data ); - pc++; - goto loop; - - case 0xD0: // BNE - BRANCH( BYTE( nz ) ); - - case 0x20: { // JSR - int temp = pc + 1; - pc = GET_ADDR(); - WRITE_STACK( SP( -1 ), temp >> 8 ); - sp = SP( -2 ); - WRITE_STACK( sp, temp ); - goto loop; - } - - case 0x4C: // JMP abs - pc = GET_ADDR(); - goto loop; - - case 0xE8: // INX - INC_DEC( 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( !BYTE( nz ) ); - - case 0x95: // STA zp,x - data = BYTE( data + x ); - case 0x85: // STA zp - pc++; - WRITE_LOW( data, a ); - goto loop; - - case 0xC8: // INY - INC_DEC( y, 1 ) - - case 0xA8: // TAY - y = a; - nz = a; - goto loop; - - case 0x98: // TYA - a = y; - nz = y; - goto loop; - - case 0xAD:{// LDA abs - int addr = GET_ADDR(); - pc += 2; - READ_PPU( addr, a = nz ); - goto loop; - } - - case 0x60: // RTS - pc = 1 + READ_STACK( sp ); - pc += 0x100 * READ_STACK( SP( 1 ) ); - sp = SP( 2 ); - goto loop; - - { - int addr; - - case 0x8D: // STA abs - addr = GET_ADDR(); - pc += 2; - if ( CAN_WRITE_FAST( addr ) ) - { - WRITE_FAST( addr, a ); - goto loop; - } - sta_ptr: - FLUSH_TIME(); - WRITE_MEM( addr, a ); - CACHE_TIME(); - goto loop; - - case 0x99: // STA abs,Y - addr = y + GET_ADDR(); - pc += 2; - if ( CAN_WRITE_FAST( addr ) ) - { - WRITE_FAST( addr, a ); - goto loop; - } - goto sta_abs_x; - - case 0x9D: // STA abs,X (slightly more common than STA abs) - addr = x + GET_ADDR(); - pc += 2; - if ( CAN_WRITE_FAST( addr ) ) - { - WRITE_FAST( addr, a ); - goto loop; - } - DUMMY_READ( addr, x ); - sta_abs_x: - FLUSH_TIME(); - WRITE_MEM( addr, a ); - CACHE_TIME(); - goto loop; - - case 0x91: // STA (ind),Y - #define NO_PAGE_PENALTY( lsb ) - IND_Y( NO_PAGE_PENALTY, addr ) - pc++; - DUMMY_READ( addr, y ); - 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 - { - int 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; - PAGE_PENALTY( addr ); - addr += 0x100 * READ_LOW( BYTE( data + 1 ) ); - pc++; - READ_FAST( addr, a = nz ); - if ( CAN_READ_FAST( addr ) ) - goto loop; - DUMMY_READ( addr, y ); - goto a_nz_read_addr; - - case 0xB9: // LDA abs,Y - PAGE_PENALTY( data + y ); - addr = GET_ADDR() + y; - pc += 2; - READ_FAST( addr, a = nz ); - if ( CAN_READ_FAST( addr ) ) - goto loop; - goto a_nz_read_addr; - - case 0xBD: // LDA abs,X - PAGE_PENALTY( data + x ); - addr = GET_ADDR() + x; - pc += 2; - READ_FAST( addr, a = nz ); - if ( CAN_READ_FAST( addr ) ) - goto loop; - DUMMY_READ( addr, x ); - a_nz_read_addr: - FLUSH_TIME(); - a = nz = READ_MEM( addr ); - CACHE_TIME(); - goto loop; - - } - -// Branch - - case 0x50: // BVC - BRANCH( !(flags & v40) ) - - case 0x70: // BVS - BRANCH( flags & v40 ) - - case 0xB0: // BCS - BRANCH( c & 0x100 ) - - case 0x90: // BCC - BRANCH( !(c & 0x100) ) - -// Load/store - - case 0x94: // STY zp,x - data = BYTE( data + x ); - case 0x84: // STY zp - pc++; - WRITE_LOW( data, y ); - goto loop; - - case 0x96: // STX zp,y - data = BYTE( data + y ); - case 0x86: // STX zp - pc++; - WRITE_LOW( data, x ); - goto loop; - - case 0xB6: // LDX zp,y - data = BYTE( 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 = BYTE( 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; - PAGE_PENALTY( data ); - case 0xAC:{// LDY abs - int addr = data + 0x100 * GET_MSB(); - pc += 2; - FLUSH_TIME(); - y = nz = READ_MEM( addr ); - CACHE_TIME(); - goto loop; - } - - case 0xBE: // LDX abs,y - data += y; - PAGE_PENALTY( data ); - case 0xAE:{// LDX abs - int addr = data + 0x100 * GET_MSB(); - pc += 2; - FLUSH_TIME(); - x = nz = READ_MEM( addr ); - CACHE_TIME(); - goto loop; - } - - { - int temp; - case 0x8C: // STY abs - temp = y; - goto store_abs; - - case 0x8E: // STX abs - temp = x; - store_abs: - { - int addr = GET_ADDR(); - pc += 2; - if ( CAN_WRITE_FAST( addr ) ) - { - WRITE_FAST( addr, temp ); - goto loop; - } - FLUSH_TIME(); - WRITE_MEM( addr, temp ); - CACHE_TIME(); - goto loop; - } - } - -// Compare - - case 0xEC: {// CPX abs - int addr = GET_ADDR(); - pc++; - FLUSH_TIME(); - data = READ_MEM( 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 - int addr = GET_ADDR(); - pc++; - FLUSH_TIME(); - data = READ_MEM( 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 - int addr = GET_ADDR(); - pc += 2; - READ_PPU( addr, nz ); - flags = (flags & ~v40) + (nz & v40); - 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++; - flags = (flags & ~v40) + (nz & v40); - if ( a & nz ) - goto loop; // Z should be clear, and nz must be non-zero if nz & a is - nz <<= 8; // set Z flag without affecting N flag - 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: { - int carry = c >> 8 & 1; - int ov = (a ^ 0x80) + carry + SBYTE( data ); - flags = (flags & ~v40) + (ov >> 2 & v40); - c = nz = a + data + carry; - pc++; - a = BYTE( 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 = BYTE( nz ); - goto loop; - - case 0x2A: { // ROL A - nz = a << 1; - int temp = c >> 8 & 1; - c = nz; - nz += temp; - a = BYTE( nz ); - goto loop; - } - - case 0x5E: // LSR abs,X - data += x; - case 0x4E: // LSR abs - c = 0; - case 0x6E: // ROR abs - ror_abs: { - ADD_PAGE( data ); - FLUSH_TIME(); - int temp = READ_MEM( 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( data ); - nz = c >> 8 & 1; - FLUSH_TIME(); - nz += (c = READ_MEM( data ) << 1); - rotate_common: - pc++; - WRITE_MEM( data, BYTE( nz ) ); - CACHE_TIME(); - goto loop; - - case 0x7E: // ROR abs,X - data += x; - goto ror_abs; - - case 0x76: // ROR zp,x - data = BYTE( data + x ); - goto ror_zp; - - case 0x56: // LSR zp,x - data = BYTE( 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 = BYTE( data + x ); - goto rol_zp; - - case 0x16: // ASL zp,x - data = BYTE( 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( x, -1 ) - - case 0x88: // DEY - INC_DEC( y, -1 ) - - case 0xF6: // INC zp,x - data = BYTE( data + x ); - case 0xE6: // INC zp - nz = 1; - goto add_nz_zp; - - case 0xD6: // DEC zp,x - data = BYTE( data + x ); - case 0xC6: // DEC zp - nz = -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 = -1; - inc_common: - FLUSH_TIME(); - pc += 2; - nz += READ_MEM( data ); - WRITE_MEM( data, BYTE( nz ) ); - CACHE_TIME(); - goto loop; - -// Transfer - - case 0xAA: // TAX - x = nz = a; - goto loop; - - case 0x8A: // TXA - a = 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 - sp = SP( -1 ); - WRITE_STACK( sp, a ); - goto loop; - - case 0x68: // PLA - a = nz = READ_STACK( sp ); - sp = SP( 1 ); - goto loop; - - case 0x40:{// RTI - pc = READ_STACK( SP( 1 ) ); - pc += READ_STACK( SP( 2 ) ) * 0x100; - int temp = READ_STACK( sp ); - sp = SP( 3 ); - data = flags; - SET_FLAGS( temp ); - cpu->r.flags = flags; // update externally-visible I flag - int delta = s.base - cpu->irq_time; - if ( delta <= 0 ) goto loop; // end_time < irq_time - if ( flags & i04 ) goto loop; - s_time += delta; - s.base = cpu->irq_time; - goto loop; - } - - case 0x28:{// PLP - int temp = READ_STACK( sp ); - sp = SP( 1 ); - int changed = flags ^ temp; - SET_FLAGS( temp ); - if ( !(changed & i04) ) - goto loop; // I flag didn't change - if ( flags & i04 ) - goto handle_sei; - goto handle_cli; - } - - case 0x08:{// PHP - int temp; - GET_FLAGS( temp ); - sp = SP( -1 ); - WRITE_STACK( sp, temp | (b10 | r20) ); - goto loop; - } - - case 0x6C:{// JMP (ind) - data = GET_ADDR(); - byte const* page = CODE_PAGE( data ); - pc = page [CODE_OFFSET( data )]; - data = (data & 0xFF00) + ((data + 1) & 0xFF); - pc += page [CODE_OFFSET( data )] * 0x100; - goto loop; - } - - case 0x00: // BRK - goto handle_brk; - -// Flags - - case 0x38: // SEC - c = 0x100; - goto loop; - - case 0x18: // CLC - c = 0; - goto loop; - - case 0xB8: // CLV - flags &= ~v40; - goto loop; - - case 0xD8: // CLD - flags &= ~d08; - goto loop; - - case 0xF8: // SED - flags |= d08; - goto loop; - - case 0x58: // CLI - if ( !(flags & i04) ) - goto loop; - flags &= ~i04; - handle_cli: { - //dprintf( "CLI at %d\n", TIME ); - cpu->r.flags = flags; // update externally-visible I flag - int delta = s.base - cpu->irq_time; - if ( delta <= 0 ) - { - if ( TIME() < cpu->irq_time ) - goto loop; - goto delayed_cli; - } - s.base = cpu->irq_time; - s_time += delta; - if ( s_time < 0 ) - goto loop; - - if ( delta >= s_time + 1 ) - { - // delayed irq until after next instruction - s.base += s_time + 1; - s_time = -1; - goto loop; - } - - // TODO: implement - delayed_cli: - dprintf( "Delayed CLI not emulated\n" ); - goto loop; - } - - case 0x78: // SEI - if ( flags & i04 ) - goto loop; - flags |= i04; - handle_sei: { - cpu->r.flags = flags; // update externally-visible I flag - int delta = s.base - cpu->end_time; - s.base = cpu->end_time; - s_time += delta; - if ( s_time < 0 ) - goto loop; - - dprintf( "Delayed SEI not emulated\n" ); - goto loop; - } - -// Unofficial - - // SKW - skip word - case 0x1C: case 0x3C: case 0x5C: case 0x7C: case 0xDC: case 0xFC: - PAGE_PENALTY( 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 halt_opcode: // HLT - halt processor - if ( pc-- > 0x10000 ) - { - // handle wrap-around (assumes caller has put page of HLT at 0x10000) - pc = WORD( pc ); - goto loop; - } - case 0x02: case 0x12: case 0x32: case 0x42: case 0x52: - case 0x62: case 0x72: case 0x92: case 0xB2: case 0xD2: case 0xF2: - goto stop; - -// Unimplemented - - case 0xFF: // force 256-entry jump table for optimization purposes - c |= 1; // compiler doesn't know that this won't affect anything - default: - check( (unsigned) opcode < 0x100 ); - - #ifdef UNIMPL_INSTR - UNIMPL_INSTR(); - #endif - - // At least skip over proper number of bytes instruction uses - static unsigned char const illop_lens [8] = { - 0x40, 0x40, 0x40, 0x80, 0x40, 0x40, 0x80, 0xA0 - }; - int opcode = instr [-1]; - int len = illop_lens [opcode >> 2 & 7] >> (opcode << 1 & 6) & 3; - if ( opcode == 0x9C ) - len = 2; - pc += len; - - // Account for extra clock - if ( (opcode >> 4) == 0x0B ) - { - if ( opcode == 0xB3 ) - data = READ_LOW( data ); - if ( opcode != 0xB7 ) - PAGE_PENALTY( data + y ); - } - goto loop; - } - assert( false ); // catch missing 'goto loop' or accidental 'break' - - int result_; -handle_brk: - pc++; - result_ = b10 | 4; - -#ifdef CPU_DONE -interrupt: -#endif - { - s_time += 7; - - // Save PC and read vector - WRITE_STACK( SP( -1 ), pc >> 8 ); - WRITE_STACK( SP( -2 ), pc ); - pc = GET_LE16( &READ_CODE( 0xFFFA ) + (result_ & 4) ); - - // Save flags - int temp; - GET_FLAGS( temp ); - temp |= r20 + (result_ & b10); // B flag set for BRK - sp = SP( -3 ); - WRITE_STACK( sp, temp ); - - // Update I flag in externally-visible flags - cpu->r.flags = (flags |= i04); - - // Update time - int delta = s.base - cpu->end_time; - if ( delta >= 0 ) - goto loop; - s_time += delta; - s.base = cpu->end_time; - goto loop; - } - -out_of_time: - pc--; - - // Optional action that triggers interrupt or changes irq/end time - #ifdef CPU_DONE - { - CPU_DONE( result_ ); - if ( result_ >= 0 ) - goto interrupt; - if ( s_time < 0 ) - goto loop; - } - #endif -stop: - - // Flush cached state - cpu->r.pc = pc; - cpu->r.sp = GET_SP(); - cpu->r.a = a; - cpu->r.x = x; - cpu->r.y = y; - - int temp; - GET_FLAGS( temp ); - cpu->r.flags = temp; - - cpu->cpu_state_.base = s.base; - cpu->cpu_state_.time = s_time; - cpu->cpu_state = &cpu->cpu_state_; -} |