diff options
Diffstat (limited to 'lib/nes/ref/cpu.cc')
| -rw-r--r-- | lib/nes/ref/cpu.cc | 1358 |
1 files changed, 0 insertions, 1358 deletions
diff --git a/lib/nes/ref/cpu.cc b/lib/nes/ref/cpu.cc deleted file mode 100644 index 79b0c56..0000000 --- a/lib/nes/ref/cpu.cc +++ /dev/null @@ -1,1358 +0,0 @@ -#include "nes/ref/cpu.hh" -#include "nes/ref/ppu.hh" -#include "nes/ref/controller.hh" -#include "nes/ref/mapper.hh" -#include "nes/util/snapshot.hh" - -namespace nes::ref -{ - cpu::cpu(ppu& ppu, mapper& mapper, controller& controller_1, controller& controller_2) - : ppu_{ ppu } - , mapper_{ mapper } - , controller_1_{ controller_1 } - , controller_2_{ controller_2 } - { - registers_.pc = read16(address{ 0xFFFC }); - } - - auto cpu::build_snapshot(snapshot& snapshot) -> void - { - snapshot.cpu_cycle = current_cycles_; - snapshot.ram = std::vector(std::begin(ram_), std::end(ram_)); - snapshot.registers.pc = registers_.pc; - snapshot.registers.sp = registers_.sp; - snapshot.registers.a = registers_.a; - snapshot.registers.x = registers_.x; - snapshot.registers.y = registers_.y; - snapshot.registers.p = registers_.p; - snapshot.registers.c = registers_.c; - snapshot.registers.z = registers_.z; - snapshot.registers.i = registers_.i; - snapshot.registers.d = registers_.d; - snapshot.registers.b = registers_.b; - snapshot.registers.v = registers_.v; - snapshot.registers.n = registers_.n; - } - - auto cpu::stall_cycles(cycle_count const count) -> void - { - current_cycles_ += count; - } - - auto cpu::trigger_nmi() -> void - { - nmi_pending_ = true; - } - - auto cpu::step() -> void - { - // See https://www.nesdev.org/wiki/CPU_unofficial_opcodes - -#ifdef NES_ENABLE_PPU - if (nmi_pending_) - { - execute_interrupt(address{ 0xFFFA }); - nmi_pending_ = false; - } -#endif - - auto const opcode = advance_pc8(); - switch (opcode) - { - case 0x00: run_brk<addressing_mode::immediate>(); break; - case 0x01: run_ora<addressing_mode::indexed_indirect>(); break; - case 0x02: run_stp(); break; - case 0x03: run_slo<addressing_mode::indexed_indirect>(); break; - case 0x04: run_nop<addressing_mode::zero_page>(); break; - case 0x05: run_ora<addressing_mode::zero_page>(); break; - case 0x06: run_asl<addressing_mode::zero_page>(); break; - case 0x07: run_slo<addressing_mode::zero_page>(); break; - case 0x08: run_php(); break; - case 0x09: run_ora<addressing_mode::immediate>(); break; - case 0x0A: run_asl<addressing_mode::accumulator>(); break; - case 0x0B: run_anc<addressing_mode::immediate>(); break; - case 0x0C: run_nop<addressing_mode::absolute>(); break; - case 0x0D: run_ora<addressing_mode::absolute>(); break; - case 0x0E: run_asl<addressing_mode::absolute>(); break; - case 0x0F: run_slo<addressing_mode::absolute>(); break; - case 0x10: run_bpl<addressing_mode::relative>(); break; - case 0x11: run_ora<addressing_mode::indirect_indexed>(); break; - case 0x12: run_stp(); break; - case 0x13: run_slo<addressing_mode::indirect_indexed>(); break; - case 0x14: run_nop<addressing_mode::zero_page_indexed_x>(); break; - case 0x15: run_ora<addressing_mode::zero_page_indexed_x>(); break; - case 0x16: run_asl<addressing_mode::zero_page_indexed_x>(); break; - case 0x17: run_slo<addressing_mode::zero_page_indexed_x>(); break; - case 0x18: run_clc(); break; - case 0x19: run_ora<addressing_mode::absolute_indexed_y>(); break; - case 0x1A: run_nop(); break; - case 0x1B: run_slo<addressing_mode::absolute_indexed_y>(); break; - case 0x1C: run_nop<addressing_mode::absolute_indexed_x>(); break; - case 0x1D: run_ora<addressing_mode::absolute_indexed_x>(); break; - case 0x1E: run_asl<addressing_mode::absolute_indexed_x>(); break; - case 0x1F: run_slo<addressing_mode::absolute_indexed_x>(); break; - case 0x20: run_jsr<addressing_mode::absolute>(); break; - case 0x21: run_and<addressing_mode::indexed_indirect>(); break; - case 0x22: run_stp(); break; - case 0x23: run_rla<addressing_mode::indexed_indirect>(); break; - case 0x24: run_bit<addressing_mode::zero_page>(); break; - case 0x25: run_and<addressing_mode::zero_page>(); break; - case 0x26: run_rol<addressing_mode::zero_page>(); break; - case 0x27: run_rla<addressing_mode::zero_page>(); break; - case 0x28: run_plp(); break; - case 0x29: run_and<addressing_mode::immediate>(); break; - case 0x2A: run_rol<addressing_mode::accumulator>(); break; - case 0x2B: run_anc<addressing_mode::immediate>(); break; - case 0x2C: run_bit<addressing_mode::absolute>(); break; - case 0x2D: run_and<addressing_mode::absolute>(); break; - case 0x2E: run_rol<addressing_mode::absolute>(); break; - case 0x2F: run_rla<addressing_mode::absolute>(); break; - case 0x30: run_bmi<addressing_mode::relative>(); break; - case 0x31: run_and<addressing_mode::indirect_indexed>(); break; - case 0x32: run_stp(); break; - case 0x33: run_rla<addressing_mode::indirect_indexed>(); break; - case 0x34: run_nop<addressing_mode::zero_page_indexed_x>(); break; - case 0x35: run_and<addressing_mode::zero_page_indexed_x>(); break; - case 0x36: run_rol<addressing_mode::zero_page_indexed_x>(); break; - case 0x37: run_rla<addressing_mode::zero_page_indexed_x>(); break; - case 0x38: run_sec(); break; - case 0x39: run_and<addressing_mode::absolute_indexed_y>(); break; - case 0x3A: run_nop(); break; - case 0x3B: run_rla<addressing_mode::absolute_indexed_y>(); break; - case 0x3C: run_nop<addressing_mode::absolute_indexed_x>(); break; - case 0x3D: run_and<addressing_mode::absolute_indexed_x>(); break; - case 0x3E: run_rol<addressing_mode::absolute_indexed_x>(); break; - case 0x3F: run_rla<addressing_mode::absolute_indexed_x>(); break; - case 0x40: run_rti(); break; - case 0x41: run_eor<addressing_mode::indexed_indirect>(); break; - case 0x42: run_stp(); break; - case 0x43: run_sre<addressing_mode::indexed_indirect>(); break; - case 0x44: run_nop<addressing_mode::zero_page>(); break; - case 0x45: run_eor<addressing_mode::zero_page>(); break; - case 0x46: run_lsr<addressing_mode::zero_page>(); break; - case 0x47: run_sre<addressing_mode::zero_page>(); break; - case 0x48: run_pha(); break; - case 0x49: run_eor<addressing_mode::immediate>(); break; - case 0x4A: run_lsr<addressing_mode::accumulator>(); break; - case 0x4B: run_alr<addressing_mode::immediate>(); break; - case 0x4C: run_jmp<addressing_mode::absolute>(); break; - case 0x4D: run_eor<addressing_mode::absolute>(); break; - case 0x4E: run_lsr<addressing_mode::absolute>(); break; - case 0x4F: run_sre<addressing_mode::absolute>(); break; - case 0x50: run_bvc<addressing_mode::relative>(); break; - case 0x51: run_eor<addressing_mode::indirect_indexed>(); break; - case 0x52: run_stp(); break; - case 0x53: run_sre<addressing_mode::indirect_indexed>(); break; - case 0x54: run_nop<addressing_mode::zero_page_indexed_x>(); break; - case 0x55: run_eor<addressing_mode::zero_page_indexed_x>(); break; - case 0x56: run_lsr<addressing_mode::zero_page_indexed_x>(); break; - case 0x57: run_sre<addressing_mode::zero_page_indexed_x>(); break; - case 0x58: run_cli(); break; - case 0x59: run_eor<addressing_mode::absolute_indexed_y>(); break; - case 0x5A: run_nop(); break; - case 0x5B: run_sre<addressing_mode::absolute_indexed_y>(); break; - case 0x5C: run_nop<addressing_mode::absolute_indexed_x>(); break; - case 0x5D: run_eor<addressing_mode::absolute_indexed_x>(); break; - case 0x5E: run_lsr<addressing_mode::absolute_indexed_x>(); break; - case 0x5F: run_sre<addressing_mode::absolute_indexed_x>(); break; - case 0x60: run_rts(); break; - case 0x61: run_adc<addressing_mode::indexed_indirect>(); break; - case 0x62: run_stp(); break; - case 0x63: run_rra<addressing_mode::indexed_indirect>(); break; - case 0x64: run_nop<addressing_mode::zero_page>(); break; - case 0x65: run_adc<addressing_mode::zero_page>(); break; - case 0x66: run_ror<addressing_mode::zero_page>(); break; - case 0x67: run_rra<addressing_mode::zero_page>(); break; - case 0x68: run_pla(); break; - case 0x69: run_adc<addressing_mode::immediate>(); break; - case 0x6A: run_ror<addressing_mode::accumulator>(); break; - case 0x6B: run_arr<addressing_mode::immediate>(); break; - case 0x6C: run_jmp<addressing_mode::indirect>(); break; - case 0x6D: run_adc<addressing_mode::absolute>(); break; - case 0x6E: run_ror<addressing_mode::absolute>(); break; - case 0x6F: run_rra<addressing_mode::absolute>(); break; - case 0x70: run_bvs<addressing_mode::relative>(); break; - case 0x71: run_adc<addressing_mode::indirect_indexed>(); break; - case 0x72: run_stp(); break; - case 0x73: run_rra<addressing_mode::indirect_indexed>(); break; - case 0x74: run_nop<addressing_mode::zero_page_indexed_x>(); break; - case 0x75: run_adc<addressing_mode::zero_page_indexed_x>(); break; - case 0x76: run_ror<addressing_mode::zero_page_indexed_x>(); break; - case 0x77: run_rra<addressing_mode::zero_page_indexed_x>(); break; - case 0x78: run_sei(); break; - case 0x79: run_adc<addressing_mode::absolute_indexed_y>(); break; - case 0x7A: run_nop(); break; - case 0x7B: run_rra<addressing_mode::absolute_indexed_y>(); break; - case 0x7C: run_nop<addressing_mode::absolute_indexed_x>(); break; - case 0x7D: run_adc<addressing_mode::absolute_indexed_x>(); break; - case 0x7E: run_ror<addressing_mode::absolute_indexed_x>(); break; - case 0x7F: run_rra<addressing_mode::absolute_indexed_x>(); break; - case 0x80: run_nop<addressing_mode::immediate>(); break; - case 0x81: run_sta<addressing_mode::indexed_indirect>(); break; - case 0x82: run_nop<addressing_mode::immediate>(); break; - case 0x83: run_sax<addressing_mode::indexed_indirect>(); break; - case 0x84: run_sty<addressing_mode::zero_page>(); break; - case 0x85: run_sta<addressing_mode::zero_page>(); break; - case 0x86: run_stx<addressing_mode::zero_page>(); break; - case 0x87: run_sax<addressing_mode::zero_page>(); break; - case 0x88: run_dey(); break; - case 0x89: run_nop<addressing_mode::immediate>(); break; - case 0x8A: run_txa(); break; - case 0x8B: run_xaa<addressing_mode::immediate>(); break; - case 0x8C: run_sty<addressing_mode::absolute>(); break; - case 0x8D: run_sta<addressing_mode::absolute>(); break; - case 0x8E: run_stx<addressing_mode::absolute>(); break; - case 0x8F: run_sax<addressing_mode::absolute>(); break; - case 0x90: run_bcc<addressing_mode::relative>(); break; - case 0x91: run_sta<addressing_mode::indirect_indexed>(); break; - case 0x92: run_stp(); break; - case 0x93: run_ahx<addressing_mode::indirect_indexed>(); break; - case 0x94: run_sty<addressing_mode::zero_page_indexed_x>(); break; - case 0x95: run_sta<addressing_mode::zero_page_indexed_x>(); break; - case 0x96: run_stx<addressing_mode::zero_page_indexed_y>(); break; - case 0x97: run_sax<addressing_mode::zero_page_indexed_y>(); break; - case 0x98: run_tya(); break; - case 0x99: run_sta<addressing_mode::absolute_indexed_y>(); break; - case 0x9A: run_txs(); break; - case 0x9B: run_tas<addressing_mode::absolute_indexed_y>(); break; - case 0x9C: run_shy<addressing_mode::absolute_indexed_x>(); break; - case 0x9D: run_sta<addressing_mode::absolute_indexed_x>(); break; - case 0x9E: run_shx<addressing_mode::absolute_indexed_y>(); break; - case 0x9F: run_ahx<addressing_mode::absolute_indexed_y>(); break; - case 0xA0: run_ldy<addressing_mode::immediate>(); break; - case 0xA1: run_lda<addressing_mode::indexed_indirect>(); break; - case 0xA2: run_ldx<addressing_mode::immediate>(); break; - case 0xA3: run_lax<addressing_mode::indexed_indirect>(); break; - case 0xA4: run_ldy<addressing_mode::zero_page>(); break; - case 0xA5: run_lda<addressing_mode::zero_page>(); break; - case 0xA6: run_ldx<addressing_mode::zero_page>(); break; - case 0xA7: run_lax<addressing_mode::zero_page>(); break; - case 0xA8: run_tay(); break; - case 0xA9: run_lda<addressing_mode::immediate>(); break; - case 0xAA: run_tax(); break; - case 0xAB: run_lax<addressing_mode::immediate>(); break; - case 0xAC: run_ldy<addressing_mode::absolute>(); break; - case 0xAD: run_lda<addressing_mode::absolute>(); break; - case 0xAE: run_ldx<addressing_mode::absolute>(); break; - case 0xAF: run_lax<addressing_mode::absolute>(); break; - case 0xB0: run_bcs<addressing_mode::relative>(); break; - case 0xB1: run_lda<addressing_mode::indirect_indexed>(); break; - case 0xB2: run_stp(); break; - case 0xB3: run_lax<addressing_mode::indirect_indexed>(); break; - case 0xB4: run_ldy<addressing_mode::zero_page_indexed_x>(); break; - case 0xB5: run_lda<addressing_mode::zero_page_indexed_x>(); break; - case 0xB6: run_ldx<addressing_mode::zero_page_indexed_y>(); break; - case 0xB7: run_lax<addressing_mode::zero_page_indexed_y>(); break; - case 0xB8: run_clv(); break; - case 0xB9: run_lda<addressing_mode::absolute_indexed_y>(); break; - case 0xBA: run_tsx(); break; - case 0xBB: run_las<addressing_mode::absolute_indexed_y>(); break; - case 0xBC: run_ldy<addressing_mode::absolute_indexed_x>(); break; - case 0xBD: run_lda<addressing_mode::absolute_indexed_x>(); break; - case 0xBE: run_ldx<addressing_mode::absolute_indexed_y>(); break; - case 0xBF: run_lax<addressing_mode::absolute_indexed_y>(); break; - case 0xC0: run_cpy<addressing_mode::immediate>(); break; - case 0xC1: run_cmp<addressing_mode::indexed_indirect>(); break; - case 0xC2: run_nop<addressing_mode::immediate>(); break; - case 0xC3: run_dcp<addressing_mode::indexed_indirect>(); break; - case 0xC4: run_cpy<addressing_mode::zero_page>(); break; - case 0xC5: run_cmp<addressing_mode::zero_page>(); break; - case 0xC6: run_dec<addressing_mode::zero_page>(); break; - case 0xC7: run_dcp<addressing_mode::zero_page>(); break; - case 0xC8: run_iny(); break; - case 0xC9: run_cmp<addressing_mode::immediate>(); break; - case 0xCA: run_dex(); break; - case 0xCB: run_axs<addressing_mode::immediate>(); break; - case 0xCC: run_cpy<addressing_mode::absolute>(); break; - case 0xCD: run_cmp<addressing_mode::absolute>(); break; - case 0xCE: run_dec<addressing_mode::absolute>(); break; - case 0xCF: run_dcp<addressing_mode::absolute>(); break; - case 0xD0: run_bne<addressing_mode::relative>(); break; - case 0xD1: run_cmp<addressing_mode::indirect_indexed>(); break; - case 0xD2: run_stp(); break; - case 0xD3: run_dcp<addressing_mode::indirect_indexed>(); break; - case 0xD4: run_nop<addressing_mode::zero_page_indexed_x>(); break; - case 0xD5: run_cmp<addressing_mode::zero_page_indexed_x>(); break; - case 0xD6: run_dec<addressing_mode::zero_page_indexed_x>(); break; - case 0xD7: run_dcp<addressing_mode::zero_page_indexed_x>(); break; - case 0xD8: run_cld(); break; - case 0xD9: run_cmp<addressing_mode::absolute_indexed_y>(); break; - case 0xDA: run_nop(); break; - case 0xDB: run_dcp<addressing_mode::absolute_indexed_y>(); break; - case 0xDC: run_nop<addressing_mode::absolute_indexed_x>(); break; - case 0xDD: run_cmp<addressing_mode::absolute_indexed_x>(); break; - case 0xDE: run_dec<addressing_mode::absolute_indexed_x>(); break; - case 0xDF: run_dcp<addressing_mode::absolute_indexed_x>(); break; - case 0xE0: run_cpx<addressing_mode::immediate>(); break; - case 0xE1: run_sbc<addressing_mode::indexed_indirect>(); break; - case 0xE2: run_nop<addressing_mode::immediate>(); break; - case 0xE3: run_isc<addressing_mode::indexed_indirect>(); break; - case 0xE4: run_cpx<addressing_mode::zero_page>(); break; - case 0xE5: run_sbc<addressing_mode::zero_page>(); break; - case 0xE6: run_inc<addressing_mode::zero_page>(); break; - case 0xE7: run_isc<addressing_mode::zero_page>(); break; - case 0xE8: run_inx(); break; - case 0xE9: run_sbc<addressing_mode::immediate>(); break; - case 0xEA: run_nop(); break; - case 0xEB: run_sbc<addressing_mode::immediate>(); break; - case 0xEC: run_cpx<addressing_mode::absolute>(); break; - case 0xED: run_sbc<addressing_mode::absolute>(); break; - case 0xEE: run_inc<addressing_mode::absolute>(); break; - case 0xEF: run_isc<addressing_mode::absolute>(); break; - case 0xF0: run_beq<addressing_mode::relative>(); break; - case 0xF1: run_sbc<addressing_mode::indirect_indexed>(); break; - case 0xF2: run_stp(); break; - case 0xF3: run_isc<addressing_mode::indirect_indexed>(); break; - case 0xF4: run_nop<addressing_mode::zero_page_indexed_x>(); break; - case 0xF5: run_sbc<addressing_mode::zero_page_indexed_x>(); break; - case 0xF6: run_inc<addressing_mode::zero_page_indexed_x>(); break; - case 0xF7: run_isc<addressing_mode::zero_page_indexed_x>(); break; - case 0xF8: run_sed(); break; - case 0xF9: run_sbc<addressing_mode::absolute_indexed_y>(); break; - case 0xFA: run_nop(); break; - case 0xFB: run_isc<addressing_mode::absolute_indexed_y>(); break; - case 0xFC: run_nop<addressing_mode::absolute_indexed_x>(); break; - case 0xFD: run_sbc<addressing_mode::absolute_indexed_x>(); break; - case 0xFE: run_inc<addressing_mode::absolute_indexed_x>(); break; - case 0xFF: run_isc<addressing_mode::absolute_indexed_x>(); break; - default: std::abort(); - } - } - - // ----------------------------------------------------------------------------------------------------------------- - // Instructions - // ----------------------------------------------------------------------------------------------------------------- - - template<cpu::addressing_mode Mode> - auto cpu::run_brk() -> void - { - // BRK: Break - fetch_operand<Mode>(); - execute_interrupt(address{ 0xFFFE }); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_ora() -> void - { - // ORA: Logical Inclusive OR - auto operand = fetch_operand<Mode>(); - eval_ora(operand.read()); - current_cycles_ += operand.get_cycles(); - } - - auto cpu::run_stp() -> void - { - // TODO: Proper STP handling - std::abort(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_slo() -> void - { - // SLO: ASL + ORA - auto operand = fetch_operand<Mode>(force_page_crossing::yes); - auto const tmp = eval_asl(operand.read()); - operand.write(tmp); - eval_ora(tmp); - current_cycles_ += operand.get_cycles() + cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_nop() -> void - { - // NOP: NOP - auto operand = fetch_operand<Mode>(); - current_cycles_ += operand.get_cycles(); - } - - auto cpu::run_nop() -> void - { - // NOP: NOP - current_cycles_ += cycle_count::from_cpu(2); - } - - auto cpu::run_php() -> void - { - // PHP: Push Processor Status - eval_php(); - current_cycles_ += cycle_count::from_cpu(3); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_asl() -> void - { - // ASL: Arithmetic Shift Left - auto operand = fetch_operand<Mode>(); - operand.write(eval_asl(operand.read())); - current_cycles_ += shift_cycle_count<Mode>(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_anc() -> void - { - // ANC: AND #i + copy N to C - auto operand = fetch_operand<Mode>(); - eval_and(operand.read()); - registers_.c = registers_.n; - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_bpl() -> void - { - // BPL: Break If Positive - branch<Mode>(!registers_.n); - } - - auto cpu::run_clc() -> void - { - // CLC: Clear Carry Flag - registers_.c = false; - current_cycles_ += cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_jsr() -> void - { - // JSR: Jump to Subroutine - static_assert(Mode == addressing_mode::absolute, "JSR only supports absolute addressing."); - - push_stack16(registers_.pc + 1); - - auto operand = fetch_operand<Mode>(); - registers_.pc = operand.get_address().get_absolute(); - current_cycles_ += cycle_count::from_cpu(6); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_and() -> void - { - // AND: Logical AND - auto operand = fetch_operand<Mode>(); - eval_and(operand.read()); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_rla() -> void - { - // RLA: ROL + AND - auto operand = fetch_operand<Mode>(force_page_crossing::yes); - auto const tmp = eval_rol(operand.read()); - operand.write(tmp); - eval_and(tmp); - current_cycles_ += operand.get_cycles() + cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_bit() -> void - { - // BIT: Bit Test - auto operand = fetch_operand<Mode>(); - auto const arg = operand.read(); - auto const res = (registers_.a & arg) != 0; - registers_.z = res == 0; - registers_.v = (arg & 0x40) != 0; - registers_.n = (arg & 0x80) != 0; - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_rol() -> void - { - // ROR: Rotate Left - auto operand = fetch_operand<Mode>(); - auto const result = eval_rol(operand.read()); - operand.write(result); - current_cycles_ += shift_cycle_count<Mode>(); - } - - auto cpu::run_plp() -> void - { - // PLP: Pull Processor Status - eval_plp(); - current_cycles_ += cycle_count::from_cpu(4); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_bmi() -> void - { - branch<Mode>(registers_.n); - } - - auto cpu::run_sec() -> void - { - // SEC: Set Carry Flag - registers_.c = true; - current_cycles_ += cycle_count::from_cpu(2); - } - - auto cpu::run_rti() -> void - { - // RTI: Return From Interrupt - eval_plp(); - registers_.pc = pop_stack16(); - current_cycles_ += cycle_count::from_cpu(6); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_eor() -> void - { - // EOR: Exclusive OR - auto operand = fetch_operand<Mode>(); - eval_eor(operand.read()); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_sre() -> void - { - // SRE: LSR + EOR - auto operand = fetch_operand<Mode>(force_page_crossing::yes); - auto const tmp = eval_lsr(operand.read()); - operand.write(tmp); - eval_eor(tmp); - current_cycles_ += operand.get_cycles() + cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_lsr() -> void - { - // LSR: Logical Shift Right - auto operand = fetch_operand<Mode>(); - auto const old_val = operand.read(); - auto const new_val = static_cast<std::uint8_t>(old_val >> 1); - operand.write(new_val); - registers_.c = (old_val & 0x1) != 0; - update_zn(new_val); - current_cycles_ += shift_cycle_count<Mode>(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_alr() -> void - { - // ALR: AND #i + LSR A - auto operand = fetch_operand<Mode>(); - eval_and(operand.read()); - registers_.a = eval_lsr(registers_.a); - current_cycles_ += operand.get_cycles(); - } - - auto cpu::run_pha() -> void - { - // PHA: Push Accumulator - push_stack8(registers_.a); - current_cycles_ += cycle_count::from_cpu(3); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_jmp() -> void - { - // JMP: Jump - auto operand = fetch_operand<Mode>(); - registers_.pc = operand.get_address().get_absolute(); - current_cycles_ += jump_cycle_count<Mode>(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_bvc() -> void - { - // BVC: Branch If Overflow Clear - branch<Mode>(!registers_.v); - } - - auto cpu::run_cli() -> void - { - // CLI: Clear Interrupt Disable - registers_.i = false; - current_cycles_ += cycle_count::from_cpu(2); - } - - auto cpu::run_rts() -> void - { - // RTS: Return from Subroutine - auto const addr = address{ pop_stack16() } + 1; - registers_.pc = addr.get_absolute(); - current_cycles_ += cycle_count::from_cpu(6); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_adc() -> void - { - // ADC: Add With Carry - auto operand = fetch_operand<Mode>(); - eval_adc(operand.read()); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_rra() -> void - { - // RRA: ROR + ADC - auto operand = fetch_operand<Mode>(force_page_crossing::yes); - auto const tmp = eval_ror(operand.read()); - operand.write(tmp); - eval_adc(tmp); - current_cycles_ += operand.get_cycles() + cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_ror() -> void - { - // ROR: Rotate Right - auto operand = fetch_operand<Mode>(); - auto const result = eval_ror(operand.read()); - operand.write(result); - current_cycles_ += shift_cycle_count<Mode>(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_arr() -> void - { - // ARR: AND #i + ROR A but with different flags - // TODO - std::abort(); - } - - auto cpu::run_pla() -> void - { - // PLA: Pull Accumulator - registers_.a = pop_stack8(); - update_zn(registers_.a); - current_cycles_ += cycle_count::from_cpu(4); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_bvs() -> void - { - // BVS: Branch If Overflow Set - branch<Mode>(registers_.v); - } - - auto cpu::run_sei() -> void - { - // SEI: Set Interrupt Disable - registers_.i = true; - current_cycles_ += cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_sta() -> void - { - // STA: Store Accumulator - auto operand = fetch_operand<Mode>(force_page_crossing::yes); - operand.write(registers_.a); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_ahx() -> void - { - // AHX: ??? - // TODO - std::abort(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_sax() -> void - { - // SAX: AND A X - auto operand = fetch_operand<Mode>(); - auto const result = static_cast<std::uint8_t>(registers_.a & registers_.x); - operand.write(result); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_sty() -> void - { - // STX: Store Y - auto operand = fetch_operand<Mode>(); - operand.write(registers_.y); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_stx() -> void - { - // STX: Store X - auto operand = fetch_operand<Mode>(); - operand.write(registers_.x); - current_cycles_ += operand.get_cycles(); - } - - auto cpu::run_dey() -> void - { - // DEY: Decrement Y Register - registers_.y -= 1; - update_zn(registers_.y); - current_cycles_ += cycle_count::from_cpu(2); - } - - auto cpu::run_txa() -> void - { - // TXA: Transfer X to Accumulator - registers_.a = registers_.x; - update_zn(registers_.a); - current_cycles_ += cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_xaa() -> void - { - // XAA: Depends on analog behavior. - run_stp(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_bcc() -> void - { - // BCC: Branch If Carry Clear - branch<Mode>(!registers_.c); - } - - auto cpu::run_tya() -> void - { - // TYA: Transfer Y to Accumulator - registers_.a = registers_.y; - update_zn(registers_.a); - current_cycles_ += cycle_count::from_cpu(2); - } - - auto cpu::run_txs() -> void - { - // TXS: Transfer X to Stack Pointer - registers_.sp = registers_.x; - current_cycles_ += cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_tas() -> void - { - // TAS: ??? - // TODO - std::abort(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_shy() -> void - { - // SHY: ??? - // TODO - std::abort(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_shx() -> void - { - // SHY: ??? - // TODO - std::abort(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_ldy() -> void - { - // LDY: Load Y Register - auto operand = fetch_operand<Mode>(); - registers_.y = operand.read(); - update_zn(registers_.y); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_lda() -> void - { - // LDA: Load Accumulator - auto operand = fetch_operand<Mode>(); - registers_.a = operand.read(); - update_zn(registers_.a); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_ldx() -> void - { - // LDX: Load X Register - auto operand = fetch_operand<Mode>(); - registers_.x = operand.read(); - update_zn(registers_.x); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_lax() -> void - { - // LAX: LDA + TAX - auto operand = fetch_operand<Mode>(); - registers_.x = registers_.a = operand.read(); - update_zn(registers_.a); - current_cycles_ += operand.get_cycles(); - } - - auto cpu::run_tay() -> void - { - // TAY: Transfer Accumulator to Y - registers_.y = registers_.a; - update_zn(registers_.y); - current_cycles_ += cycle_count::from_cpu(2); - } - - auto cpu::run_tax() -> void - { - // TAX: Transfer Accumulator to X - registers_.x = registers_.a; - update_zn(registers_.x); - current_cycles_ += cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_bcs() -> void - { - // BCS: Branch If Carry Set - branch<Mode>(registers_.c); - } - - auto cpu::run_clv() -> void - { - // CLV: Clear Overflow Flag - registers_.v = false; - current_cycles_ += cycle_count::from_cpu(2); - } - - auto cpu::run_tsx() -> void - { - // TSX: Transfer Stack Pointer to X - registers_.x = registers_.sp; - update_zn(registers_.x); - current_cycles_ += cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_las() -> void - { - // LAS: ??? - // TODO - std::abort(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_cpy() -> void - { - // CPY: Compare Y Register - auto operand = fetch_operand<Mode>(); - eval_cmp(registers_.y, operand.read()); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_axs() -> void - { - // AXS: Set X to ((A AND X) - #value without borrow), updates NZC - // TODO - std::abort(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_cmp() -> void - { - // CMP: Compare - auto operand = fetch_operand<Mode>(); - eval_cmp(registers_.a, operand.read()); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_dcp() -> void - { - // DCP: DEC + CMP - auto operand = fetch_operand<Mode>(force_page_crossing::yes); - auto const tmp = static_cast<std::uint8_t>(operand.read() - 1); - operand.write(tmp); - eval_cmp(registers_.a, tmp); - current_cycles_ += operand.get_cycles() + cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_dec() -> void - { - // DEC: Decrement Memory - auto operand = fetch_operand<Mode>(); - auto const old_val = read8(operand.get_address()); - auto const new_val = static_cast<std::uint8_t>(old_val - 1); - write8(operand.get_address(), new_val); - update_zn(new_val); - current_cycles_ += inc_dec_cycle_count<Mode>(); - } - - auto cpu::run_iny() -> void - { - // INY: Increment Y - registers_.y += 1; - update_zn(registers_.y); - current_cycles_ += cycle_count::from_cpu(2); - } - - auto cpu::run_dex() -> void - { - // DEX: Decrement X Register - registers_.x -= 1; - update_zn(registers_.x); - current_cycles_ += cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_bne() -> void - { - // BNE: Branch If Not Equal - branch<Mode>(!registers_.z); - } - - auto cpu::run_cld() -> void - { - // CLD: Clear Decimal Mode - registers_.d = false; - current_cycles_ += cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_cpx() -> void - { - // CPX: Compare X Register - auto operand = fetch_operand<Mode>(); - eval_cmp(registers_.x, operand.read()); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_sbc() -> void - { - // SBC: Subtract With Carry - auto operand = fetch_operand<Mode>(); - eval_adc(~operand.read()); - current_cycles_ += operand.get_cycles(); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_isc() -> void - { - // ISC: INC + SBC - auto operand = fetch_operand<Mode>(force_page_crossing::yes); - auto const tmp = static_cast<std::uint8_t>(operand.read() + 1); - operand.write(tmp); - eval_adc(~tmp); - current_cycles_ += operand.get_cycles() + cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_inc() -> void - { - // INC: Increment Memory - auto operand = fetch_operand<Mode>(); - auto const old_val = read8(operand.get_address()); - auto const new_val = static_cast<std::uint8_t>(old_val + 1); - write8(operand.get_address(), new_val); - update_zn(new_val); - current_cycles_ += inc_dec_cycle_count<Mode>(); - } - - auto cpu::run_inx() -> void - { - // INX: Increment X - registers_.x += 1; - update_zn(registers_.x); - current_cycles_ += cycle_count::from_cpu(2); - } - - template<cpu::addressing_mode Mode> - auto cpu::run_beq() -> void - { - // BEQ: Branch If Equal - branch<Mode>(registers_.z); - } - - auto cpu::run_sed() -> void - { - // SED: Set Decimal Flag - registers_.d = true; - current_cycles_ += cycle_count::from_cpu(2); - } - - // ----------------------------------------------------------------------------------------------------------------- - // Helpers - // ----------------------------------------------------------------------------------------------------------------- - - auto cpu::advance_pc8() -> std::uint8_t - { - auto const val = read8(address{ registers_.pc }); - registers_.pc += 1; - return val; - } - - auto cpu::advance_pc16() -> std::uint16_t - { - auto const val = read16(address{ registers_.pc }); - registers_.pc += 2; - return val; - } - - auto cpu::push_stack8(std::uint8_t const value) -> void - { - write8(stack_offset + registers_.sp, value); - registers_.sp -= 1; - } - - auto cpu::push_stack16(std::uint16_t const value) -> void - { - auto const low = static_cast<std::uint8_t>(value >> 0 & 0xFF); - auto const high = static_cast<std::uint8_t>(value >> 8 & 0xFF); - push_stack8(high); - push_stack8(low); - } - - auto cpu::pop_stack8() -> std::uint8_t - { - registers_.sp += 1; - return read8(stack_offset + registers_.sp); - } - - auto cpu::pop_stack16() -> std::uint16_t - { - auto const low = pop_stack8(); - auto const high = pop_stack8(); - return static_cast<std::uint16_t>((high << 8) | (low << 0)); - } - - auto cpu::update_zn(std::uint8_t const value) -> void - { - registers_.z = value == 0; - registers_.n = (value & 0x80) != 0; - } - - template<cpu::addressing_mode Mode> - auto cpu::branch(bool const condition) -> void - { - static_assert(Mode == addressing_mode::relative, "Branch should only be used with relative operands."); - - auto operand = fetch_operand<Mode>(); - if (condition) - { - registers_.pc = operand.get_address().get_absolute(); - current_cycles_ += operand.get_cycles(); - } - else - { - current_cycles_ += cycle_count::from_cpu(2); - } - } - - auto cpu::execute_interrupt(address const vector) -> void - { - push_stack16(registers_.pc); - eval_php(); - registers_.pc = read16(vector); - registers_.i = true; - current_cycles_ += cycle_count::from_cpu(7); - } - - auto cpu::eval_ror(std::uint8_t const arg) -> std::uint8_t - { - auto const res = static_cast<std::uint8_t>((registers_.c << 7) | (arg >> 1)); - registers_.c = (arg & 0x1) != 0; - update_zn(res); - return res; - } - - auto cpu::eval_rol(std::uint8_t const arg) -> std::uint8_t - { - auto const res = static_cast<std::uint8_t>((arg << 1) | (registers_.c ? 1 : 0)); - registers_.c = (arg & 0x80) != 0; - update_zn(res); - return res; - } - - auto cpu::eval_asl(std::uint8_t const arg) -> std::uint8_t - { - auto const new_val = static_cast<std::uint8_t>(arg << 1); - registers_.c = (arg & 0x80) != 0; - update_zn(new_val); - return new_val; - } - - auto cpu::eval_lsr(std::uint8_t const arg) -> std::uint8_t - { - auto const new_val = static_cast<std::uint8_t>(arg >> 1); - registers_.c = (arg & 0x01) != 0; - update_zn(new_val); - return new_val; - } - - auto cpu::eval_adc(std::uint8_t const arg) -> void - { - auto const old_val = registers_.a; - auto const tmp = old_val + arg + (registers_.c ? 1 : 0); - auto const new_val = static_cast<std::uint8_t>(tmp); - - registers_.a = new_val; - registers_.c = tmp > 0xFF; - registers_.v = ((old_val ^ arg) & 0x80) == 0 && ((old_val ^ new_val) & 0x80) != 0; - update_zn(registers_.a); - } - - auto cpu::eval_and(std::uint8_t const arg) -> void - { - registers_.a &= arg; - update_zn(registers_.a); - } - - auto cpu::eval_ora(std::uint8_t const arg) -> void - { - registers_.a |= arg; - update_zn(registers_.a); - } - - auto cpu::eval_eor(std::uint8_t const arg) -> void - { - registers_.a ^= arg; - update_zn(registers_.a); - } - - auto cpu::eval_cmp(std::uint8_t const a, std::uint8_t const b) -> void - { - update_zn(a - b); - registers_.c = a >= b; - } - - auto cpu::eval_plp() -> void - { - // Ignore bits 4 and 5 - registers_.p = - (pop_stack8() & 0b11001111) | - (registers_.p & 0b00110000); - } - - auto cpu::eval_php() -> void - { - // Always set bits 4 and 5. - push_stack8(registers_.p | 0b00110000); - } - - // ----------------------------------------------------------------------------------------------------------------- - // Operands - // ----------------------------------------------------------------------------------------------------------------- - - // - // See: https://www.nesdev.org/wiki/CPU_addressing_modes - // - - template<cpu::addressing_mode Mode> - auto cpu::fetch_operand(force_page_crossing const force_page_crossing) -> operand<Mode> - { - auto addr = address{}; - auto cycles = cycle_count{}; - - switch (Mode) - { - case addressing_mode::immediate: static_assert(Mode != addressing_mode::immediate); - case addressing_mode::accumulator: static_assert(Mode != addressing_mode::accumulator); - case addressing_mode::zero_page: - { - addr = address{ advance_pc8() }; - cycles = cycle_count::from_cpu(3); - break; - } - case addressing_mode::absolute: - { - addr = address{ advance_pc16() }; - cycles = cycle_count::from_cpu(4); - break; - } - case addressing_mode::relative: - { - auto const offset = static_cast<std::int8_t>(advance_pc8()); - auto const base = address{ registers_.pc }; - addr = address{ static_cast<std::uint16_t>(registers_.pc + offset) }; - auto const page_crossing = - base.get_page() != addr.get_page() || force_page_crossing == force_page_crossing::yes; - cycles = cycle_count::from_cpu(page_crossing ? 4 : 3); - break; - } - case addressing_mode::indirect: - { - auto const arg = address{ advance_pc16() }; - // Account for buggy indirect read: https://www.nesdev.org/wiki/Errata - addr = arg.get_offset() == 0xFF - ? address{ read8(address{ arg.get_page(), 0x00 }), read8(arg) } - : address{ read16(arg) }; - cycles = cycle_count::from_cpu(6); - break; - } - case addressing_mode::zero_page_indexed_x: - { - // PEEK((arg + X) % 256) - addr = address{ 0x00, static_cast<std::uint8_t>(advance_pc8() + registers_.x) }; - cycles = cycle_count::from_cpu(4); - break; - } - case addressing_mode::zero_page_indexed_y: - { - // PEEK((arg + Y) % 256) - addr = address{ 0x00, static_cast<std::uint8_t>(advance_pc8() + registers_.y) }; - cycles = cycle_count::from_cpu(4); - break; - } - case addressing_mode::absolute_indexed_x: - { - // PEEK(arg + X) - auto const arg = address{ advance_pc16() }; - addr = arg + registers_.x; - auto const page_crossing = - addr.get_page() != arg.get_page() || force_page_crossing == force_page_crossing::yes; - cycles = cycle_count::from_cpu(page_crossing ? 5 : 4); - break; - } - case addressing_mode::absolute_indexed_y: - { - // PEEK(arg + Y) - auto const arg = address{ advance_pc16() }; - addr = arg + registers_.y; - auto const page_crossing = - addr.get_page() != arg.get_page() || force_page_crossing == force_page_crossing::yes; - cycles = cycle_count::from_cpu(page_crossing ? 5 : 4); - break; - } - case addressing_mode::indexed_indirect: - { - // PEEK(PEEK((arg + X) % 256) + PEEK((arg + X + 1) % 256) * 256) - auto const arg = advance_pc8(); - auto const page = read8(address{ 0x00, static_cast<std::uint8_t>(arg + registers_.x + 1) }); - auto const offset = read8(address{ 0x00, static_cast<std::uint8_t>(arg + registers_.x) }); - addr = address{ page, offset }; - cycles = cycle_count::from_cpu(6); - break; - } - case addressing_mode::indirect_indexed: - { - // PEEK(PEEK(arg) + PEEK((arg + 1) % 256) * 256 + Y) - auto const arg = advance_pc8(); - auto const page = read8(address{ 0x00, static_cast<std::uint8_t>(arg + 1) }); - auto const offset = read8(address{ 0x00, static_cast<std::uint8_t>(arg) }); - auto const base = address{ page, offset }; - addr = base + registers_.y; - auto const page_crossing = - addr.get_page() != base.get_page() || force_page_crossing == force_page_crossing::yes; - cycles = cycle_count::from_cpu(page_crossing ? 6 : 5); - break; - } - } - - return operand<Mode>{ *this, addr, cycles }; - } - - template<> - auto cpu::fetch_operand<cpu::addressing_mode::accumulator>(force_page_crossing) - -> operand<addressing_mode::accumulator> - { - return operand<addressing_mode::accumulator>{ *this }; - } - - template<> - auto cpu::fetch_operand<cpu::addressing_mode::immediate>(force_page_crossing) - -> operand<addressing_mode::immediate> - { - return operand<addressing_mode::immediate>{ advance_pc8() }; - } - - // ----------------------------------------------------------------------------------------------------------------- - // Memory Access - // ----------------------------------------------------------------------------------------------------------------- - - // - // See: https://www.nesdev.org/wiki/CPU_memory_map - // - - auto cpu::read8(address const addr) -> std::uint8_t - { - if (addr <= address{ 0x1FFF }) { return ram_[addr.get_absolute() % ram_size]; } - if (addr <= address{ 0x3FFF }) - { -#ifdef NES_ENABLE_PPU - switch (addr.get_absolute() % 8) - { - case 0: return ppu_.read_latch(); - case 1: return ppu_.read_latch(); - case 2: return ppu_.read_ppustatus(); - case 3: return ppu_.read_latch(); - case 4: return ppu_.read_oamdata(); - case 5: return ppu_.read_latch(); - case 6: return ppu_.read_latch(); - case 7: return ppu_.read_ppudata(); - default: return 0x0; - } -#else - return 0x0; -#endif - } - if (addr <= address{ 0x4013 }) { return 0x0; } // TODO: APU registers -#ifdef NES_ENABLE_PPU - if (addr == address{ 0x4014 }) { return ppu_.read_latch(); } -#else - if (addr == address{ 0x4014 }) { return 0x0; } -#endif - if (addr == address{ 0x4015 }) { return 0x0; } // TODO: APU registers - if (addr == address{ 0x4016 }) { return controller_1_.read(); } - if (addr == address{ 0x4017 }) { return controller_2_.read(); } - if (addr <= address{ 0x401F }) { return 0x0; } - return mapper_.read_cpu(addr); - } - - auto cpu::read16(address const addr) -> std::uint16_t - { - auto const low = read8(addr + 0); - auto const high = read8(addr + 1); - return static_cast<std::uint16_t>((high << 8) | (low << 0)); - } - - auto cpu::write8(address const addr, std::uint8_t const value) -> void - { - if (addr <= address{ 0x1FFF }) { ram_[addr.get_absolute() % ram_size] = value; return; } - if (addr <= address{ 0x3FFF }) - { -#ifdef NES_ENABLE_PPU - switch (addr.get_absolute() % 8) - { - case 0: ppu_.write_ppuctrl(value); return; - case 1: ppu_.write_ppumask(value); return; - case 2: ppu_.write_latch(value); return; - case 3: ppu_.write_oamaddr(value); return; - case 4: ppu_.write_oamdata(value); return; - case 5: ppu_.write_ppuscroll(value); return; - case 6: ppu_.write_ppuaddr(value); return; - case 7: ppu_.write_ppudata(value); return; - default: return; - } -#else - return; -#endif - } - if (addr <= address{ 0x4013 }) { return; } // TODO: APU registers -#ifdef NES_ENABLE_PPU - if (addr == address{ 0x4014 }) { ppu_.write_oamdma(value); return; } -#else - if (addr == address{ 0x4014 }) { return; } -#endif - if (addr == address{ 0x4015 }) { return; } // TODO: APU registers - if (addr == address{ 0x4016 }) { controller_1_.write(value); return; } - if (addr == address{ 0x4017 }) { controller_2_.write(value); return; } - if (addr <= address{ 0x401F }) { return; } - mapper_.write_cpu(addr, value); - } - - auto cpu::write16(address const addr, std::uint16_t const value) -> void - { - auto const low = static_cast<std::uint8_t>(value >> 0 & 0xFF); - auto const high = static_cast<std::uint8_t>(value >> 8 & 0xFF); - write8(addr + 0, low); - write8(addr + 1, high); - } -} // namespace nes::ref
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