From 5959349f341a2380c0c3f41ec40a1e8e0d969d00 Mon Sep 17 00:00:00 2001 From: Hannes Schulze Date: Wed, 29 Jan 2025 14:49:20 +0100 Subject: refactor: move emulation logic into sys --- lib/nes/cpu.cc | 1425 -------------------------------------------------------- 1 file changed, 1425 deletions(-) delete mode 100644 lib/nes/cpu.cc (limited to 'lib/nes/cpu.cc') diff --git a/lib/nes/cpu.cc b/lib/nes/cpu.cc deleted file mode 100644 index cf8943f..0000000 --- a/lib/nes/cpu.cc +++ /dev/null @@ -1,1425 +0,0 @@ -#include "nes/cpu.hh" -#include "nes/ppu.hh" -#include "nes/controller.hh" -#include "nes/cartridge.hh" -#include "nes/util/snapshot.hh" - -namespace nes -{ - cpu::cpu(ppu& ppu, cartridge& cartridge, controller& controller_1, controller& controller_2) - : ppu_{ ppu } - , cartridge_{ cartridge } - , 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.value; - snapshot.registers.c = registers_.p.get_c(); - snapshot.registers.z = registers_.p.get_z(); - snapshot.registers.i = registers_.p.get_i(); - snapshot.registers.d = registers_.p.get_d(); - snapshot.registers.b = registers_.p.get_b(); - snapshot.registers.v = registers_.p.get_v(); - snapshot.registers.n = registers_.p.get_n(); - } - - auto cpu::stall_cycles(cycle_count const count) -> void - { - current_cycles_ += count; - } - - auto cpu::trigger_nmi() -> void - { - nmi_pending_ = true; - } - - auto cpu::step() -> status - { - // 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: return run_brk(); - case 0x01: return run_ora(); - case 0x02: return run_stp(); - case 0x03: return run_slo(); - case 0x04: return run_nop(); - case 0x05: return run_ora(); - case 0x06: return run_asl(); - case 0x07: return run_slo(); - case 0x08: return run_php(); - case 0x09: return run_ora(); - case 0x0A: return run_asl(); - case 0x0B: return run_anc(); - case 0x0C: return run_nop(); - case 0x0D: return run_ora(); - case 0x0E: return run_asl(); - case 0x0F: return run_slo(); - case 0x10: return run_bpl(); - case 0x11: return run_ora(); - case 0x12: return run_stp(); - case 0x13: return run_slo(); - case 0x14: return run_nop(); - case 0x15: return run_ora(); - case 0x16: return run_asl(); - case 0x17: return run_slo(); - case 0x18: return run_clc(); - case 0x19: return run_ora(); - case 0x1A: return run_nop(); - case 0x1B: return run_slo(); - case 0x1C: return run_nop(); - case 0x1D: return run_ora(); - case 0x1E: return run_asl(); - case 0x1F: return run_slo(); - case 0x20: return run_jsr(); - case 0x21: return run_and(); - case 0x22: return run_stp(); - case 0x23: return run_rla(); - case 0x24: return run_bit(); - case 0x25: return run_and(); - case 0x26: return run_rol(); - case 0x27: return run_rla(); - case 0x28: return run_plp(); - case 0x29: return run_and(); - case 0x2A: return run_rol(); - case 0x2B: return run_anc(); - case 0x2C: return run_bit(); - case 0x2D: return run_and(); - case 0x2E: return run_rol(); - case 0x2F: return run_rla(); - case 0x30: return run_bmi(); - case 0x31: return run_and(); - case 0x32: return run_stp(); - case 0x33: return run_rla(); - case 0x34: return run_nop(); - case 0x35: return run_and(); - case 0x36: return run_rol(); - case 0x37: return run_rla(); - case 0x38: return run_sec(); - case 0x39: return run_and(); - case 0x3A: return run_nop(); - case 0x3B: return run_rla(); - case 0x3C: return run_nop(); - case 0x3D: return run_and(); - case 0x3E: return run_rol(); - case 0x3F: return run_rla(); - case 0x40: return run_rti(); - case 0x41: return run_eor(); - case 0x42: return run_stp(); - case 0x43: return run_sre(); - case 0x44: return run_nop(); - case 0x45: return run_eor(); - case 0x46: return run_lsr(); - case 0x47: return run_sre(); - case 0x48: return run_pha(); - case 0x49: return run_eor(); - case 0x4A: return run_lsr(); - case 0x4B: return run_alr(); - case 0x4C: return run_jmp(); - case 0x4D: return run_eor(); - case 0x4E: return run_lsr(); - case 0x4F: return run_sre(); - case 0x50: return run_bvc(); - case 0x51: return run_eor(); - case 0x52: return run_stp(); - case 0x53: return run_sre(); - case 0x54: return run_nop(); - case 0x55: return run_eor(); - case 0x56: return run_lsr(); - case 0x57: return run_sre(); - case 0x58: return run_cli(); - case 0x59: return run_eor(); - case 0x5A: return run_nop(); - case 0x5B: return run_sre(); - case 0x5C: return run_nop(); - case 0x5D: return run_eor(); - case 0x5E: return run_lsr(); - case 0x5F: return run_sre(); - case 0x60: return run_rts(); - case 0x61: return run_adc(); - case 0x62: return run_stp(); - case 0x63: return run_rra(); - case 0x64: return run_nop(); - case 0x65: return run_adc(); - case 0x66: return run_ror(); - case 0x67: return run_rra(); - case 0x68: return run_pla(); - case 0x69: return run_adc(); - case 0x6A: return run_ror(); - case 0x6B: return run_arr(); - case 0x6C: return run_jmp(); - case 0x6D: return run_adc(); - case 0x6E: return run_ror(); - case 0x6F: return run_rra(); - case 0x70: return run_bvs(); - case 0x71: return run_adc(); - case 0x72: return run_stp(); - case 0x73: return run_rra(); - case 0x74: return run_nop(); - case 0x75: return run_adc(); - case 0x76: return run_ror(); - case 0x77: return run_rra(); - case 0x78: return run_sei(); - case 0x79: return run_adc(); - case 0x7A: return run_nop(); - case 0x7B: return run_rra(); - case 0x7C: return run_nop(); - case 0x7D: return run_adc(); - case 0x7E: return run_ror(); - case 0x7F: return run_rra(); - case 0x80: return run_nop(); - case 0x81: return run_sta(); - case 0x82: return run_nop(); - case 0x83: return run_sax(); - case 0x84: return run_sty(); - case 0x85: return run_sta(); - case 0x86: return run_stx(); - case 0x87: return run_sax(); - case 0x88: return run_dey(); - case 0x89: return run_nop(); - case 0x8A: return run_txa(); - case 0x8B: return run_xaa(); - case 0x8C: return run_sty(); - case 0x8D: return run_sta(); - case 0x8E: return run_stx(); - case 0x8F: return run_sax(); - case 0x90: return run_bcc(); - case 0x91: return run_sta(); - case 0x92: return run_stp(); - case 0x93: return run_ahx(); - case 0x94: return run_sty(); - case 0x95: return run_sta(); - case 0x96: return run_stx(); - case 0x97: return run_sax(); - case 0x98: return run_tya(); - case 0x99: return run_sta(); - case 0x9A: return run_txs(); - case 0x9B: return run_tas(); - case 0x9C: return run_shy(); - case 0x9D: return run_sta(); - case 0x9E: return run_shx(); - case 0x9F: return run_ahx(); - case 0xA0: return run_ldy(); - case 0xA1: return run_lda(); - case 0xA2: return run_ldx(); - case 0xA3: return run_lax(); - case 0xA4: return run_ldy(); - case 0xA5: return run_lda(); - case 0xA6: return run_ldx(); - case 0xA7: return run_lax(); - case 0xA8: return run_tay(); - case 0xA9: return run_lda(); - case 0xAA: return run_tax(); - case 0xAB: return run_lax(); - case 0xAC: return run_ldy(); - case 0xAD: return run_lda(); - case 0xAE: return run_ldx(); - case 0xAF: return run_lax(); - case 0xB0: return run_bcs(); - case 0xB1: return run_lda(); - case 0xB2: return run_stp(); - case 0xB3: return run_lax(); - case 0xB4: return run_ldy(); - case 0xB5: return run_lda(); - case 0xB6: return run_ldx(); - case 0xB7: return run_lax(); - case 0xB8: return run_clv(); - case 0xB9: return run_lda(); - case 0xBA: return run_tsx(); - case 0xBB: return run_las(); - case 0xBC: return run_ldy(); - case 0xBD: return run_lda(); - case 0xBE: return run_ldx(); - case 0xBF: return run_lax(); - case 0xC0: return run_cpy(); - case 0xC1: return run_cmp(); - case 0xC2: return run_nop(); - case 0xC3: return run_dcp(); - case 0xC4: return run_cpy(); - case 0xC5: return run_cmp(); - case 0xC6: return run_dec(); - case 0xC7: return run_dcp(); - case 0xC8: return run_iny(); - case 0xC9: return run_cmp(); - case 0xCA: return run_dex(); - case 0xCB: return run_axs(); - case 0xCC: return run_cpy(); - case 0xCD: return run_cmp(); - case 0xCE: return run_dec(); - case 0xCF: return run_dcp(); - case 0xD0: return run_bne(); - case 0xD1: return run_cmp(); - case 0xD2: return run_stp(); - case 0xD3: return run_dcp(); - case 0xD4: return run_nop(); - case 0xD5: return run_cmp(); - case 0xD6: return run_dec(); - case 0xD7: return run_dcp(); - case 0xD8: return run_cld(); - case 0xD9: return run_cmp(); - case 0xDA: return run_nop(); - case 0xDB: return run_dcp(); - case 0xDC: return run_nop(); - case 0xDD: return run_cmp(); - case 0xDE: return run_dec(); - case 0xDF: return run_dcp(); - case 0xE0: return run_cpx(); - case 0xE1: return run_sbc(); - case 0xE2: return run_nop(); - case 0xE3: return run_isc(); - case 0xE4: return run_cpx(); - case 0xE5: return run_sbc(); - case 0xE6: return run_inc(); - case 0xE7: return run_isc(); - case 0xE8: return run_inx(); - case 0xE9: return run_sbc(); - case 0xEA: return run_nop(); - case 0xEB: return run_sbc(); - case 0xEC: return run_cpx(); - case 0xED: return run_sbc(); - case 0xEE: return run_inc(); - case 0xEF: return run_isc(); - case 0xF0: return run_beq(); - case 0xF1: return run_sbc(); - case 0xF2: return run_stp(); - case 0xF3: return run_isc(); - case 0xF4: return run_nop(); - case 0xF5: return run_sbc(); - case 0xF6: return run_inc(); - case 0xF7: return run_isc(); - case 0xF8: return run_sed(); - case 0xF9: return run_sbc(); - case 0xFA: return run_nop(); - case 0xFB: return run_isc(); - case 0xFC: return run_nop(); - case 0xFD: return run_sbc(); - case 0xFE: return run_inc(); - case 0xFF: return run_isc(); - default: return status::error_unsupported_instruction; - } - } - - // ----------------------------------------------------------------------------------------------------------------- - // Instructions - // ----------------------------------------------------------------------------------------------------------------- - - template - auto cpu::run_brk() -> status - { - // BRK: Break - fetch_operand(); - execute_interrupt(address{ 0xFFFE }); - return status::success; - } - - template - auto cpu::run_ora() -> status - { - // ORA: Logical Inclusive OR - auto operand = fetch_operand(); - eval_ora(operand.read()); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - auto cpu::run_stp() -> status - { - return status::error_unsupported_instruction; - } - - template - auto cpu::run_slo() -> status - { - // SLO: ASL + ORA - auto operand = fetch_operand(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); - return status::success; - } - - template - auto cpu::run_nop() -> status - { - // NOP: NOP - auto operand = fetch_operand(); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - auto cpu::run_nop() -> status - { - // NOP: NOP - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - auto cpu::run_php() -> status - { - // PHP: Push Processor Status - eval_php(); - current_cycles_ += cycle_count::from_cpu(3); - return status::success; - } - - template - auto cpu::run_asl() -> status - { - // ASL: Arithmetic Shift Left - auto operand = fetch_operand(); - operand.write(eval_asl(operand.read())); - current_cycles_ += shift_cycle_count(); - return status::success; - } - - template - auto cpu::run_anc() -> status - { - // ANC: AND #i + copy N to C - auto operand = fetch_operand(); - eval_and(operand.read()); - registers_.p.set_c(registers_.p.get_n()); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_bpl() -> status - { - // BPL: Break If Positive - branch(!registers_.p.get_n()); - return status::success; - } - - auto cpu::run_clc() -> status - { - // CLC: Clear Carry Flag - registers_.p.set_c(false); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_jsr() -> status - { - // JSR: Jump to Subroutine - static_assert(Mode == addressing_mode::absolute, "JSR only supports absolute addressing."); - - push_stack16(registers_.pc + 1); - - auto operand = fetch_operand(); - registers_.pc = operand.get_address().get_absolute(); - current_cycles_ += cycle_count::from_cpu(6); - return status::success; - } - - template - auto cpu::run_and() -> status - { - // AND: Logical AND - auto operand = fetch_operand(); - eval_and(operand.read()); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_rla() -> status - { - // RLA: ROL + AND - auto operand = fetch_operand(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); - return status::success; - } - - template - auto cpu::run_bit() -> status - { - // BIT: Bit Test - auto operand = fetch_operand(); - auto const arg = operand.read(); - auto const res = (registers_.a & arg) != 0; - registers_.p.set_z(res == 0); - registers_.p.set_v((arg & 0x40) != 0); - registers_.p.set_n((arg & 0x80) != 0); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_rol() -> status - { - // ROR: Rotate Left - auto operand = fetch_operand(); - auto const result = eval_rol(operand.read()); - operand.write(result); - current_cycles_ += shift_cycle_count(); - return status::success; - } - - auto cpu::run_plp() -> status - { - // PLP: Pull Processor Status - eval_plp(); - current_cycles_ += cycle_count::from_cpu(4); - return status::success; - } - - template - auto cpu::run_bmi() -> status - { - branch(registers_.p.get_n()); - return status::success; - } - - auto cpu::run_sec() -> status - { - // SEC: Set Carry Flag - registers_.p.set_c(true); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - auto cpu::run_rti() -> status - { - // RTI: Return From Interrupt - eval_plp(); - registers_.pc = pop_stack16(); - current_cycles_ += cycle_count::from_cpu(6); - return status::success; - } - - template - auto cpu::run_eor() -> status - { - // EOR: Exclusive OR - auto operand = fetch_operand(); - eval_eor(operand.read()); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_sre() -> status - { - // SRE: LSR + EOR - auto operand = fetch_operand(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); - return status::success; - } - - template - auto cpu::run_lsr() -> status - { - // LSR: Logical Shift Right - auto operand = fetch_operand(); - auto const old_val = operand.read(); - auto const new_val = static_cast(old_val >> 1); - operand.write(new_val); - registers_.p.set_c((old_val & 0x1) != 0); - update_zn(new_val); - current_cycles_ += shift_cycle_count(); - return status::success; - } - - template - auto cpu::run_alr() -> status - { - // ALR: AND #i + LSR A - auto operand = fetch_operand(); - eval_and(operand.read()); - registers_.a = eval_lsr(registers_.a); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - auto cpu::run_pha() -> status - { - // PHA: Push Accumulator - push_stack8(registers_.a); - current_cycles_ += cycle_count::from_cpu(3); - return status::success; - } - - template - auto cpu::run_jmp() -> status - { - // JMP: Jump - auto operand = fetch_operand(); - registers_.pc = operand.get_address().get_absolute(); - current_cycles_ += jump_cycle_count(); - return status::success; - } - - template - auto cpu::run_bvc() -> status - { - // BVC: Branch If Overflow Clear - branch(!registers_.p.get_v()); - return status::success; - } - - auto cpu::run_cli() -> status - { - // CLI: Clear Interrupt Disable - registers_.p.set_i(false); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - auto cpu::run_rts() -> status - { - // RTS: Return from Subroutine - auto const addr = address{ pop_stack16() } + 1; - registers_.pc = addr.get_absolute(); - current_cycles_ += cycle_count::from_cpu(6); - return status::success; - } - - template - auto cpu::run_adc() -> status - { - // ADC: Add With Carry - auto operand = fetch_operand(); - eval_adc(operand.read()); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_rra() -> status - { - // RRA: ROR + ADC - auto operand = fetch_operand(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); - return status::success; - } - - template - auto cpu::run_ror() -> status - { - // ROR: Rotate Right - auto operand = fetch_operand(); - auto const result = eval_ror(operand.read()); - operand.write(result); - current_cycles_ += shift_cycle_count(); - return status::success; - } - - template - auto cpu::run_arr() -> status - { - // ARR: AND #i + ROR A but with different flags - // TODO - return status::error_unsupported_instruction; - } - - auto cpu::run_pla() -> status - { - // PLA: Pull Accumulator - registers_.a = pop_stack8(); - update_zn(registers_.a); - current_cycles_ += cycle_count::from_cpu(4); - return status::success; - } - - template - auto cpu::run_bvs() -> status - { - // BVS: Branch If Overflow Set - branch(registers_.p.get_v()); - return status::success; - } - - auto cpu::run_sei() -> status - { - // SEI: Set Interrupt Disable - registers_.p.set_i(true); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_sta() -> status - { - // STA: Store Accumulator - auto operand = fetch_operand(force_page_crossing::yes); - operand.write(registers_.a); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_ahx() -> status - { - // AHX: ??? - // TODO - return status::error_unsupported_instruction; - } - - template - auto cpu::run_sax() -> status - { - // SAX: AND A X - auto operand = fetch_operand(); - auto const result = static_cast(registers_.a & registers_.x); - operand.write(result); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_sty() -> status - { - // STX: Store Y - auto operand = fetch_operand(); - operand.write(registers_.y); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_stx() -> status - { - // STX: Store X - auto operand = fetch_operand(); - operand.write(registers_.x); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - auto cpu::run_dey() -> status - { - // DEY: Decrement Y Register - registers_.y -= 1; - update_zn(registers_.y); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - auto cpu::run_txa() -> status - { - // TXA: Transfer X to Accumulator - registers_.a = registers_.x; - update_zn(registers_.a); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_xaa() -> status - { - // XAA: Depends on analog behavior. - run_stp(); - return status::success; - } - - template - auto cpu::run_bcc() -> status - { - // BCC: Branch If Carry Clear - branch(!registers_.p.get_c()); - return status::success; - } - - auto cpu::run_tya() -> status - { - // TYA: Transfer Y to Accumulator - registers_.a = registers_.y; - update_zn(registers_.a); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - auto cpu::run_txs() -> status - { - // TXS: Transfer X to Stack Pointer - registers_.sp = registers_.x; - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_tas() -> status - { - // TAS: ??? - // TODO - return status::error_unsupported_instruction; - } - - template - auto cpu::run_shy() -> status - { - // SHY: ??? - // TODO - return status::error_unsupported_instruction; - } - - template - auto cpu::run_shx() -> status - { - // SHY: ??? - // TODO - return status::error_unsupported_instruction; - } - - template - auto cpu::run_ldy() -> status - { - // LDY: Load Y Register - auto operand = fetch_operand(); - registers_.y = operand.read(); - update_zn(registers_.y); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_lda() -> status - { - // LDA: Load Accumulator - auto operand = fetch_operand(); - registers_.a = operand.read(); - update_zn(registers_.a); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_ldx() -> status - { - // LDX: Load X Register - auto operand = fetch_operand(); - registers_.x = operand.read(); - update_zn(registers_.x); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_lax() -> status - { - // LAX: LDA + TAX - auto operand = fetch_operand(); - registers_.x = registers_.a = operand.read(); - update_zn(registers_.a); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - auto cpu::run_tay() -> status - { - // TAY: Transfer Accumulator to Y - registers_.y = registers_.a; - update_zn(registers_.y); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - auto cpu::run_tax() -> status - { - // TAX: Transfer Accumulator to X - registers_.x = registers_.a; - update_zn(registers_.x); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_bcs() -> status - { - // BCS: Branch If Carry Set - branch(registers_.p.get_c()); - return status::success; - } - - auto cpu::run_clv() -> status - { - // CLV: Clear Overflow Flag - registers_.p.set_v(false); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - auto cpu::run_tsx() -> status - { - // TSX: Transfer Stack Pointer to X - registers_.x = registers_.sp; - update_zn(registers_.x); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_las() -> status - { - // LAS: ??? - // TODO - return status::error_unsupported_instruction; - } - - template - auto cpu::run_cpy() -> status - { - // CPY: Compare Y Register - auto operand = fetch_operand(); - eval_cmp(registers_.y, operand.read()); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_axs() -> status - { - // AXS: Set X to ((A AND X) - #value without borrow), updates NZC - // TODO - return status::error_unsupported_instruction; - } - - template - auto cpu::run_cmp() -> status - { - // CMP: Compare - auto operand = fetch_operand(); - eval_cmp(registers_.a, operand.read()); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_dcp() -> status - { - // DCP: DEC + CMP - auto operand = fetch_operand(force_page_crossing::yes); - auto const tmp = static_cast(operand.read() - 1); - operand.write(tmp); - eval_cmp(registers_.a, tmp); - current_cycles_ += operand.get_cycles() + cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_dec() -> status - { - // DEC: Decrement Memory - auto operand = fetch_operand(); - auto const old_val = read8(operand.get_address()); - auto const new_val = static_cast(old_val - 1); - write8(operand.get_address(), new_val); - update_zn(new_val); - current_cycles_ += inc_dec_cycle_count(); - return status::success; - } - - auto cpu::run_iny() -> status - { - // INY: Increment Y - registers_.y += 1; - update_zn(registers_.y); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - auto cpu::run_dex() -> status - { - // DEX: Decrement X Register - registers_.x -= 1; - update_zn(registers_.x); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_bne() -> status - { - // BNE: Branch If Not Equal - branch(!registers_.p.get_z()); - return status::success; - } - - auto cpu::run_cld() -> status - { - // CLD: Clear Decimal Mode - registers_.p.set_d(false); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_cpx() -> status - { - // CPX: Compare X Register - auto operand = fetch_operand(); - eval_cmp(registers_.x, operand.read()); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_sbc() -> status - { - // SBC: Subtract With Carry - auto operand = fetch_operand(); - eval_adc(~operand.read()); - current_cycles_ += operand.get_cycles(); - return status::success; - } - - template - auto cpu::run_isc() -> status - { - // ISC: INC + SBC - auto operand = fetch_operand(force_page_crossing::yes); - auto const tmp = static_cast(operand.read() + 1); - operand.write(tmp); - eval_adc(~tmp); - current_cycles_ += operand.get_cycles() + cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_inc() -> status - { - // INC: Increment Memory - auto operand = fetch_operand(); - auto const old_val = read8(operand.get_address()); - auto const new_val = static_cast(old_val + 1); - write8(operand.get_address(), new_val); - update_zn(new_val); - current_cycles_ += inc_dec_cycle_count(); - return status::success; - } - - auto cpu::run_inx() -> status - { - // INX: Increment X - registers_.x += 1; - update_zn(registers_.x); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - template - auto cpu::run_beq() -> status - { - // BEQ: Branch If Equal - branch(registers_.p.get_z()); - return status::success; - } - - auto cpu::run_sed() -> status - { - // SED: Set Decimal Flag - registers_.p.set_d(true); - current_cycles_ += cycle_count::from_cpu(2); - return status::success; - } - - // ----------------------------------------------------------------------------------------------------------------- - // 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(value >> 0 & 0xFF); - auto const high = static_cast(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((high << 8) | (low << 0)); - } - - auto cpu::update_zn(std::uint8_t const value) -> void - { - registers_.p.set_z(value == 0); - registers_.p.set_n((value & 0x80) != 0); - } - - template - 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(); - 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_.p.set_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(((registers_.p.get_c() ? 1 :0) << 7) | (arg >> 1)); - registers_.p.set_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((arg << 1) | (registers_.p.get_c() ? 1 : 0)); - registers_.p.set_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(arg << 1); - registers_.p.set_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(arg >> 1); - registers_.p.set_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_.p.get_c() ? 1 : 0); - auto const new_val = static_cast(tmp); - - registers_.a = new_val; - registers_.p.set_c(tmp > 0xFF); - registers_.p.set_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_.p.set_c(a >= b); - } - - auto cpu::eval_plp() -> void - { - // Ignore bits 4 and 5 - registers_.p.value = - (pop_stack8() & 0b11001111) | - (registers_.p.value & 0b00110000); - } - - auto cpu::eval_php() -> void - { - // Always set bits 4 and 5. - push_stack8(registers_.p.value | 0b00110000); - } - - // ----------------------------------------------------------------------------------------------------------------- - // Operands - // ----------------------------------------------------------------------------------------------------------------- - - // - // See: https://www.nesdev.org/wiki/CPU_addressing_modes - // - - template - auto cpu::fetch_operand(force_page_crossing const force_page_crossing) -> operand - { - 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(advance_pc8()); - auto const base = address{ registers_.pc }; - addr = address{ static_cast(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(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(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(arg + registers_.x + 1) }); - auto const offset = read8(address{ 0x00, static_cast(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(arg + 1) }); - auto const offset = read8(address{ 0x00, static_cast(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{ *this, addr, cycles }; - } - - template<> - auto cpu::fetch_operand(force_page_crossing) - -> operand - { - return operand{ *this }; - } - - template<> - auto cpu::fetch_operand(force_page_crossing) - -> operand - { - return operand{ 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 cartridge_.get_mapper().read_cpu(addr, cartridge_); - } - - auto cpu::read16(address const addr) -> std::uint16_t - { - auto const low = read8(addr + 0); - auto const high = read8(addr + 1); - return static_cast((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; } - cartridge_.get_mapper().write_cpu(addr, value, cartridge_); - } - - auto cpu::write16(address const addr, std::uint16_t const value) -> void - { - auto const low = static_cast(value >> 0 & 0xFF); - auto const high = static_cast(value >> 8 & 0xFF); - write8(addr + 0, low); - write8(addr + 1, high); - } -} // namespace nes \ No newline at end of file -- cgit v1.3.1