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6502 Without OPs
This commit is contained in:
Nathan Bourgeois
parent
398cee8101
commit
9c78e6cbac
658
src/6502.zig
Normal file
658
src/6502.zig
Normal file
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const std = @import("std");
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const Bus = @import("bus.zig");
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const Self = @This();
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/// Accumulator Register
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rA: u8 = 0,
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/// X Register
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rX: u8 = 0,
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/// Y Register
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rY: u8 = 0,
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/// Stack Pointer (SP)
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sp: u8 = 0,
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/// Instruction Pointer (IP)
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ip: u16 = 0,
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/// Flag register
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status: u8 = 0,
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/// Reference to the system Bus
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bus: *Bus = undefined,
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/// Byte fetched from memory
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byte_fetched: u8 = 0x00,
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/// Absolute address
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addr_absolute: u16 = 0x0000,
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/// Relative address
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addr_relative: u16 = 0x0000,
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/// Opcode
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opcode: u8 = 0x00,
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/// Remaining cycles in operation
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cycles: u8 = 0x00,
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instruction_table: [256]Instruction = undefined,
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/// Flags Enum
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const Flags = enum(u3) {
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C = 0, // Carry Flag
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Z = 1, // Zero Flag
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I = 2, // Disable Interrupt Flag
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D = 3, // Decimal Mode Flag
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B = 4, // Break Flag
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U = 5, // Unused
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V = 6, // Overflow Flag
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N = 7, // Negative Flag
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};
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/// Instruction Enum
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const Instruction = struct {
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name: []const u8,
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operation: Operation,
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address_mode: AddressMode,
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cycles: u8 = 0,
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};
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/// Operations Enum
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const Operation = enum(u8) { ADC, AND, ASL, BCC, BCS, BEQ, BIT, BMI, BNE, BPL, BRK, BVC, BVS, CLC, CLD, CLI, CLV, CMP, CPX, CPY, DEC, DEX, DEY, EOR, INC, INX, INY, JMP, JSR, LDA, LDX, LDY, LSR, NOP, ORA, PHA, PHP, PLA, PLP, ROL, ROR, RTI, RTS, SBC, SEC, SED, SEI, STA, STX, STY, TAX, TAY, TSX, TXA, TXS, TYA, XXX };
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/// Address Mode Enum
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const AddressMode = enum(u8) { IMP, IMM, ZP0, ZPX, ZPY, REL, ABS, ABX, ABY, IND, IZX, IZY, XXX };
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// Implied
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fn IMP(self: *Self) u8 {
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self.byte_fetched = self.rA;
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return 0;
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}
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// Immediate (next byte = value)
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fn IMM(self: *Self) u8 {
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self.addr_absolute = self.ip;
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self.ip += 1;
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return 0;
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}
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//Zero Page (absolute address in first 0xFF of range)
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fn ZP0(self: *Self) u8 {
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self.addr_absolute = self.read(self.ip, false);
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self.ip += 1;
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self.addr_absolute &= 0x00FF;
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return 0;
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}
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// Zero Page with X Offset
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fn ZPX(self: *Self) u8 {
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self.addr_absolute = (self.read(self.ip, false) + self.rX);
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self.ip += 1;
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self.addr_absolute &= 0x00FF;
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return 0;
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}
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// Zero Page with Y Offset
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fn ZPY(self: *Self) u8 {
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self.addr_absolute = (self.read(self.ip, false) + self.rY);
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self.ip += 1;
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self.addr_absolute &= 0x00FF;
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return 0;
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}
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//Relative Branch
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fn REL(self: *Self) u8 {
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self.addr_relative = self.read(self.ip, false);
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self.ip += 1;
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if (self.addr_relative & 0x80)
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self.addr_relative |= 0xFF00;
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return 0;
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}
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//Absolute
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fn ABS(self: *Self) u8 {
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var lo: u16 = self.read(self.ip, false);
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self.ip += 1;
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var hi: u16 = self.read(self.ip, false);
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self.ip += 1;
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self.addr_absolute = (hi << 8) | (lo & 0xFF);
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return 0;
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}
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// Absolute with X Offset
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fn ABX(self: *Self) u8 {
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var lo: u16 = self.read(self.ip, false);
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self.ip += 1;
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var hi: u16 = self.read(self.ip, false);
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self.ip += 1;
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self.addr_absolute = (hi << 8) | (lo & 0xFF);
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self.addr_absolute += self.rX;
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return if ((self.addr_absolute & 0xFF00) != (hi << 8)) 1 else 0;
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}
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// Absolute with Y Offset
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fn ABY(self: *Self) u8 {
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var lo: u16 = self.read(self.ip, false);
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self.ip += 1;
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var hi: u16 = self.read(self.ip, false);
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self.ip += 1;
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self.addr_absolute = (hi << 8) | (lo & 0xFF);
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self.addr_absolute += self.rY;
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return if ((self.addr_absolute & 0xFF00) != (hi << 8)) 1 else 0;
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}
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// Indirect
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fn IND(self: *Self) u8 {
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var ptr_lo: u16 = self.read(self.ip, false);
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self.ip += 1;
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var ptr_hi: u16 = self.read(self.ip, false);
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self.ip += 1;
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var ptr = (ptr_hi << 8) | (ptr_lo & 0xFF);
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if (ptr_lo == 0x00FF) // Simulate page boundary hardware bug
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{
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self.addr_absolute = (self.read(ptr & 0xFF00, false) << 8) | self.read(ptr + 0, false);
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} else // Behave normally
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{
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self.addr_absolute = (self.read(ptr + 1, false) << 8) | self.read(ptr + 0, false);
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}
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return 0;
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}
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//Indirect X
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fn IZX(self: *Self) u8 {
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var t: u16 = self.read(self.ip, false);
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self.ip += 1;
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var lo: u16 = self.read((t + self.rX) & 0x00FF, false);
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var hi: u16 = self.read((t + self.rX + 1) & 0x00FF, false);
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self.addr_absolute = (hi << 8) | (lo & 0xFF);
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return 0;
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}
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//Indirect Y
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fn IZY(self: *Self) u8 {
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var t: u16 = self.read(self.ip, false);
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self.ip += 1;
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var lo: u16 = self.read(t & 0x00FF, false);
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var hi: u16 = self.read((t + 1) & 0x00FF, false);
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self.addr_absolute = (hi << 8) | (lo & 0xFF);
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self.addr_absolute += self.rY;
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return if ((self.addr_absolute & 0xFF00) != (hi << 8)) 1 else 0;
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}
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pub fn init(self: *Self) !void {
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self.instruction_table = .{
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Instruction{ .name = "BRK", .operation = Operation.BRK, .address_mode = AddressMode.IMM, .cycles = 7 }, Instruction{ .name = "ORA", .operation = Operation.ORA, .address_mode = AddressMode.IZX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 3 }, Instruction{ .name = "ORA", .operation = Operation.ORA, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "ASL", .operation = Operation.ASL, .address_mode = AddressMode.ZP0, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "PHP", .operation = Operation.PHP, .address_mode = AddressMode.IMP, .cycles = 3 }, Instruction{ .name = "ORA", .operation = Operation.ORA, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "ASL", .operation = Operation.ASL, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "ORA", .operation = Operation.ORA, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "ASL", .operation = Operation.ASL, .address_mode = AddressMode.ABS, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 },
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Instruction{ .name = "BPL", .operation = Operation.BPL, .address_mode = AddressMode.REL, .cycles = 2 }, Instruction{ .name = "ORA", .operation = Operation.ORA, .address_mode = AddressMode.IZY, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "ORA", .operation = Operation.ORA, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "ASL", .operation = Operation.ASL, .address_mode = AddressMode.ZPX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "CLC", .operation = Operation.CLC, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "ORA", .operation = Operation.ORA, .address_mode = AddressMode.ABY, .cycles = 4 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "ORA", .operation = Operation.ORA, .address_mode = AddressMode.ABX, .cycles = 4 }, Instruction{ .name = "ASL", .operation = Operation.ASL, .address_mode = AddressMode.ABX, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 },
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Instruction{ .name = "JSR", .operation = Operation.JSR, .address_mode = AddressMode.ABS, .cycles = 6 }, Instruction{ .name = "AND", .operation = Operation.AND, .address_mode = AddressMode.IZX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "BIT", .operation = Operation.BIT, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "AND", .operation = Operation.AND, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "ROL", .operation = Operation.ROL, .address_mode = AddressMode.ZP0, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "PLP", .operation = Operation.PLP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "AND", .operation = Operation.AND, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "ROL", .operation = Operation.ROL, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "BIT", .operation = Operation.BIT, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "AND", .operation = Operation.AND, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "ROL", .operation = Operation.ROL, .address_mode = AddressMode.ABS, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 },
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Instruction{ .name = "BMI", .operation = Operation.BMI, .address_mode = AddressMode.REL, .cycles = 2 }, Instruction{ .name = "AND", .operation = Operation.AND, .address_mode = AddressMode.IZY, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "AND", .operation = Operation.AND, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "ROL", .operation = Operation.ROL, .address_mode = AddressMode.ZPX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "SEC", .operation = Operation.SEC, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "AND", .operation = Operation.AND, .address_mode = AddressMode.ABY, .cycles = 4 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "AND", .operation = Operation.AND, .address_mode = AddressMode.ABX, .cycles = 4 }, Instruction{ .name = "ROL", .operation = Operation.ROL, .address_mode = AddressMode.ABX, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 },
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Instruction{ .name = "RTI", .operation = Operation.RTI, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "EOR", .operation = Operation.EOR, .address_mode = AddressMode.IZX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 3 }, Instruction{ .name = "EOR", .operation = Operation.EOR, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "LSR", .operation = Operation.LSR, .address_mode = AddressMode.ZP0, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "PHA", .operation = Operation.PHA, .address_mode = AddressMode.IMP, .cycles = 3 }, Instruction{ .name = "EOR", .operation = Operation.EOR, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "LSR", .operation = Operation.LSR, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "JMP", .operation = Operation.JMP, .address_mode = AddressMode.ABS, .cycles = 3 }, Instruction{ .name = "EOR", .operation = Operation.EOR, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "LSR", .operation = Operation.LSR, .address_mode = AddressMode.ABS, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 },
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Instruction{ .name = "BVC", .operation = Operation.BVC, .address_mode = AddressMode.REL, .cycles = 2 }, Instruction{ .name = "EOR", .operation = Operation.EOR, .address_mode = AddressMode.IZY, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "EOR", .operation = Operation.EOR, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "LSR", .operation = Operation.LSR, .address_mode = AddressMode.ZPX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "CLI", .operation = Operation.CLI, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "EOR", .operation = Operation.EOR, .address_mode = AddressMode.ABY, .cycles = 4 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "EOR", .operation = Operation.EOR, .address_mode = AddressMode.ABX, .cycles = 4 }, Instruction{ .name = "LSR", .operation = Operation.LSR, .address_mode = AddressMode.ABX, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 },
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Instruction{ .name = "RTS", .operation = Operation.RTS, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "ADC", .operation = Operation.ADC, .address_mode = AddressMode.IZX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 3 }, Instruction{ .name = "ADC", .operation = Operation.ADC, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "ROR", .operation = Operation.ROR, .address_mode = AddressMode.ZP0, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "PLA", .operation = Operation.PLA, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "ADC", .operation = Operation.ADC, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "ROR", .operation = Operation.ROR, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "JMP", .operation = Operation.JMP, .address_mode = AddressMode.IND, .cycles = 5 }, Instruction{ .name = "ADC", .operation = Operation.ADC, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "ROR", .operation = Operation.ROR, .address_mode = AddressMode.ABS, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 },
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Instruction{ .name = "BVS", .operation = Operation.BVS, .address_mode = AddressMode.REL, .cycles = 2 }, Instruction{ .name = "ADC", .operation = Operation.ADC, .address_mode = AddressMode.IZY, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "ADC", .operation = Operation.ADC, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "ROR", .operation = Operation.ROR, .address_mode = AddressMode.ZPX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "SEI", .operation = Operation.SEI, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "ADC", .operation = Operation.ADC, .address_mode = AddressMode.ABY, .cycles = 4 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "ADC", .operation = Operation.ADC, .address_mode = AddressMode.ABX, .cycles = 4 }, Instruction{ .name = "ROR", .operation = Operation.ROR, .address_mode = AddressMode.ABX, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 },
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Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "STA", .operation = Operation.STA, .address_mode = AddressMode.IZX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "STY", .operation = Operation.STY, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "STA", .operation = Operation.STA, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "STX", .operation = Operation.STX, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 3 }, Instruction{ .name = "DEY", .operation = Operation.DEY, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "TXA", .operation = Operation.TXA, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "STY", .operation = Operation.STY, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "STA", .operation = Operation.STA, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "STX", .operation = Operation.STX, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 4 },
|
||||
Instruction{ .name = "BCC", .operation = Operation.BCC, .address_mode = AddressMode.REL, .cycles = 2 }, Instruction{ .name = "STA", .operation = Operation.STA, .address_mode = AddressMode.IZY, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "STY", .operation = Operation.STY, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "STA", .operation = Operation.STA, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "STX", .operation = Operation.STX, .address_mode = AddressMode.ZPY, .cycles = 4 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "TYA", .operation = Operation.TYA, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "STA", .operation = Operation.STA, .address_mode = AddressMode.ABY, .cycles = 5 }, Instruction{ .name = "TXS", .operation = Operation.TXS, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "STA", .operation = Operation.STA, .address_mode = AddressMode.ABX, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 },
|
||||
Instruction{ .name = "LDY", .operation = Operation.LDY, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "LDA", .operation = Operation.LDA, .address_mode = AddressMode.IZX, .cycles = 6 }, Instruction{ .name = "LDX", .operation = Operation.LDX, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "LDY", .operation = Operation.LDY, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "LDA", .operation = Operation.LDA, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "LDX", .operation = Operation.LDX, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 3 }, Instruction{ .name = "TAY", .operation = Operation.TAY, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "LDA", .operation = Operation.LDA, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "TAX", .operation = Operation.TAX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "LDY", .operation = Operation.LDY, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "LDA", .operation = Operation.LDA, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "LDX", .operation = Operation.LDX, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 4 },
|
||||
Instruction{ .name = "BCS", .operation = Operation.BCS, .address_mode = AddressMode.REL, .cycles = 2 }, Instruction{ .name = "LDA", .operation = Operation.LDA, .address_mode = AddressMode.IZY, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "LDY", .operation = Operation.LDY, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "LDA", .operation = Operation.LDA, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "LDX", .operation = Operation.LDX, .address_mode = AddressMode.ZPY, .cycles = 4 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "CLV", .operation = Operation.CLV, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "LDA", .operation = Operation.LDA, .address_mode = AddressMode.ABY, .cycles = 4 }, Instruction{ .name = "TSX", .operation = Operation.TSX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "LDY", .operation = Operation.LDY, .address_mode = AddressMode.ABX, .cycles = 4 }, Instruction{ .name = "LDA", .operation = Operation.LDA, .address_mode = AddressMode.ABX, .cycles = 4 }, Instruction{ .name = "LDX", .operation = Operation.LDX, .address_mode = AddressMode.ABY, .cycles = 4 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 4 },
|
||||
Instruction{ .name = "CPY", .operation = Operation.CPY, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "CMP", .operation = Operation.CMP, .address_mode = AddressMode.IZX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "CPY", .operation = Operation.CPY, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "CMP", .operation = Operation.CMP, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "DEC", .operation = Operation.DEC, .address_mode = AddressMode.ZP0, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "INY", .operation = Operation.INY, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "CMP", .operation = Operation.CMP, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "DEX", .operation = Operation.DEX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "CPY", .operation = Operation.CPY, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "CMP", .operation = Operation.CMP, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "DEC", .operation = Operation.DEC, .address_mode = AddressMode.ABS, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 },
|
||||
Instruction{ .name = "BNE", .operation = Operation.BNE, .address_mode = AddressMode.REL, .cycles = 2 }, Instruction{ .name = "CMP", .operation = Operation.CMP, .address_mode = AddressMode.IZY, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "CMP", .operation = Operation.CMP, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "DEC", .operation = Operation.DEC, .address_mode = AddressMode.ZPX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "CLD", .operation = Operation.CLD, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "CMP", .operation = Operation.CMP, .address_mode = AddressMode.ABY, .cycles = 4 }, Instruction{ .name = "NOP", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "CMP", .operation = Operation.CMP, .address_mode = AddressMode.ABX, .cycles = 4 }, Instruction{ .name = "DEC", .operation = Operation.DEC, .address_mode = AddressMode.ABX, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 },
|
||||
Instruction{ .name = "CPX", .operation = Operation.CPX, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "SBC", .operation = Operation.SBC, .address_mode = AddressMode.IZX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "CPX", .operation = Operation.CPX, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "SBC", .operation = Operation.SBC, .address_mode = AddressMode.ZP0, .cycles = 3 }, Instruction{ .name = "INC", .operation = Operation.INC, .address_mode = AddressMode.ZP0, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 5 }, Instruction{ .name = "INX", .operation = Operation.INX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "SBC", .operation = Operation.SBC, .address_mode = AddressMode.IMM, .cycles = 2 }, Instruction{ .name = "NOP", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.SBC, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "CPX", .operation = Operation.CPX, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "SBC", .operation = Operation.SBC, .address_mode = AddressMode.ABS, .cycles = 4 }, Instruction{ .name = "INC", .operation = Operation.INC, .address_mode = AddressMode.ABS, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 },
|
||||
Instruction{ .name = "BEQ", .operation = Operation.BEQ, .address_mode = AddressMode.REL, .cycles = 2 }, Instruction{ .name = "SBC", .operation = Operation.SBC, .address_mode = AddressMode.IZY, .cycles = 5 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 8 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "SBC", .operation = Operation.SBC, .address_mode = AddressMode.ZPX, .cycles = 4 }, Instruction{ .name = "INC", .operation = Operation.INC, .address_mode = AddressMode.ZPX, .cycles = 6 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 6 }, Instruction{ .name = "SED", .operation = Operation.SED, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "SBC", .operation = Operation.SBC, .address_mode = AddressMode.ABY, .cycles = 4 }, Instruction{ .name = "NOP", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 2 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.NOP, .address_mode = AddressMode.IMP, .cycles = 4 }, Instruction{ .name = "SBC", .operation = Operation.SBC, .address_mode = AddressMode.ABX, .cycles = 4 }, Instruction{ .name = "INC", .operation = Operation.INC, .address_mode = AddressMode.ABX, .cycles = 7 }, Instruction{ .name = "???", .operation = Operation.XXX, .address_mode = AddressMode.IMP, .cycles = 7 },
|
||||
};
|
||||
|
||||
self.reset();
|
||||
}
|
||||
|
||||
pub fn deinit(self: *Self) void {
|
||||
self.reset();
|
||||
}
|
||||
|
||||
fn write(self: *Self, addr: u16, data: u8) void {
|
||||
self.bus.write(addr, data);
|
||||
}
|
||||
|
||||
fn read(self: *Self, addr: u16, readOnly: bool) u8 {
|
||||
return self.bus.read(addr, readOnly);
|
||||
}
|
||||
|
||||
fn getFlag(self: *Self, flag: Flags) u8 {
|
||||
return (self.status >> flag) & 1;
|
||||
}
|
||||
|
||||
fn setFlag(self: *Self, flag: Flags, value: bool) void {
|
||||
var v = @boolToInt(value);
|
||||
self.status ^= (-v ^ self.status) & (1 << flag);
|
||||
}
|
||||
|
||||
pub fn reset(self: *Self) void {
|
||||
// Reset program counter
|
||||
self.addr_absolute = 0xFFFC;
|
||||
var lo: u16 = self.read(self.addr_absolute + 0, false);
|
||||
var hi: u16 = self.read(self.addr_absolute + 0, false);
|
||||
|
||||
self.ip = (hi << 8) | (lo & 0xFF);
|
||||
|
||||
self.rA = 0x00;
|
||||
self.rX = 0x00;
|
||||
self.rY = 0x00;
|
||||
|
||||
self.sp = 0xFD;
|
||||
self.status = @as(u8, 0x00) | @enumToInt(Flags.U);
|
||||
|
||||
self.addr_absolute = 0x0000;
|
||||
self.addr_relative = 0x0000;
|
||||
|
||||
self.byte_fetched = 0x00;
|
||||
|
||||
// Takes 8 cycles to perform reset.
|
||||
self.cycles = 8;
|
||||
}
|
||||
|
||||
fn fetch(self: *Self) u8 {
|
||||
if (!(self.instruction_table[self.opcode].address_mode == AddressMode.IMP))
|
||||
self.fetched = self.read(self.addr_absolute, false);
|
||||
|
||||
return self.fetched;
|
||||
}
|
||||
|
||||
pub fn irq(self: *Self) void {
|
||||
if (self.getFlag(Flags.I) != 0)
|
||||
return;
|
||||
|
||||
// Push the program counter to the stack.
|
||||
self.write(0x0100 + self.sp, (self.ip >> 8) & 0x00FF);
|
||||
self.sp -= 1;
|
||||
self.write(0x0100 + self.sp, self.ip & 0x00FF);
|
||||
self.sp -= 1;
|
||||
|
||||
// Then Push the status register to the stack
|
||||
self.setFlag(Flags.B, false);
|
||||
self.setFlag(Flags.U, true);
|
||||
self.setFlag(Flags.I, true);
|
||||
self.write(0x0100 + self.sp, self.status);
|
||||
self.sp -= 1;
|
||||
|
||||
// Read new program counter location from fixed address
|
||||
self.addr_absolute = 0xFFFE;
|
||||
var lo: u16 = self.read(self.addr_absolute + 0);
|
||||
var hi: u16 = self.read(self.addr_absolute + 1);
|
||||
|
||||
self.ip = (hi << 8) | (lo & 0xFF);
|
||||
self.cycles = 7;
|
||||
}
|
||||
|
||||
pub fn nmi(self: *Self) void {
|
||||
self.write(0x0100 + self.sp, (self.ip >> 8) & 0x00FF);
|
||||
self.sp -= 1;
|
||||
write(0x0100 + self.sp, self.ip & 0x00FF);
|
||||
self.sp -= 1;
|
||||
|
||||
self.setFlag(Flags.B, false);
|
||||
self.setFlag(Flags.U, true);
|
||||
self.setFlag(Flags.I, true);
|
||||
self.write(0x0100 + self.sp, self.status);
|
||||
self.sp -= 1;
|
||||
|
||||
self.addr_absolute = 0xFFFA;
|
||||
var lo: u16 = read(self.addr_absolute + 0);
|
||||
var hi: u16 = read(self.addr_absolute + 1);
|
||||
self.ip = (hi << 8) | (lo & 0xFF);
|
||||
|
||||
self.cycles = 8;
|
||||
}
|
||||
|
||||
pub fn clock(self: *Self) void {
|
||||
if (self.cycles == 0) {
|
||||
//Do next operation
|
||||
self.opcode = self.read(self.ip, false);
|
||||
self.setFlag(Flags.U, true);
|
||||
|
||||
self.ip += 1;
|
||||
|
||||
// Calculate number of cycles
|
||||
var addressing_cycles: u8 = self.performAddressing();
|
||||
|
||||
if (addressing_cycles == 255) {
|
||||
@panic("Addressing Mode is invalid!");
|
||||
}
|
||||
|
||||
var operation_cycles: u8 = self.performOperation();
|
||||
|
||||
if (operation_cycles == 255) {
|
||||
@panic("Addressing Mode is invalid!");
|
||||
}
|
||||
|
||||
self.cycles = self.instruction_table[self.opcode].cycles + addressing_cycles + operation_cycles;
|
||||
}
|
||||
|
||||
self.cycles -= 1;
|
||||
}
|
||||
|
||||
pub fn performAddressing(self: *Self) u8 {
|
||||
var addrMode = self.instruction_table[self.opcode].address_mode;
|
||||
|
||||
return switch (addrMode) {
|
||||
.IMP => self.IMP(),
|
||||
.IMM => self.IMM(),
|
||||
.ZP0 => self.ZP0(),
|
||||
.ZPX => self.ZPX(),
|
||||
.ZPY => self.ZPY(),
|
||||
.REL => self.REL(),
|
||||
.ABS => self.ABS(),
|
||||
.ABX => self.ABX(),
|
||||
.ABY => self.ABY(),
|
||||
.IND => self.IND(),
|
||||
.IZX => self.IZX(),
|
||||
.IZY => self.IZY(),
|
||||
else => 255,
|
||||
};
|
||||
}
|
||||
|
||||
pub fn performOperation(self: *Self) u8 {
|
||||
var operation = self.instruction_table[self.opcode].operation;
|
||||
|
||||
return switch (operation) {
|
||||
.ADC => self.ADC(),
|
||||
.AND => self.AND(),
|
||||
.ASL => self.ASL(),
|
||||
.BCC => self.BCC(),
|
||||
.BCS => self.BCS(),
|
||||
.BEQ => self.BEQ(),
|
||||
.BIT => self.BIT(),
|
||||
.BMI => self.BMI(),
|
||||
.BNE => self.BNE(),
|
||||
.BPL => self.BPL(),
|
||||
.BRK => self.BRK(),
|
||||
.BVC => self.BVC(),
|
||||
.BVS => self.BVS(),
|
||||
.CLC => self.CLC(),
|
||||
.CLD => self.CLD(),
|
||||
.CLI => self.CLI(),
|
||||
.CLV => self.CLV(),
|
||||
.CMP => self.CMP(),
|
||||
.CPX => self.CPX(),
|
||||
.CPY => self.CPY(),
|
||||
.DEC => self.DEC(),
|
||||
.DEX => self.DEX(),
|
||||
.DEY => self.DEY(),
|
||||
.EOR => self.EOR(),
|
||||
.INC => self.INC(),
|
||||
.INX => self.INX(),
|
||||
.INY => self.INY(),
|
||||
.JMP => self.JMP(),
|
||||
.JSR => self.JSR(),
|
||||
.LDA => self.LDA(),
|
||||
.LDX => self.LDX(),
|
||||
.LDY => self.LDY(),
|
||||
.LSR => self.LSR(),
|
||||
.NOP => self.NOP(),
|
||||
.ORA => self.ORA(),
|
||||
.PHA => self.PHA(),
|
||||
.PHP => self.PHP(),
|
||||
.PLA => self.PLA(),
|
||||
.PLP => self.PLP(),
|
||||
.ROL => self.ROL(),
|
||||
.ROR => self.ROR(),
|
||||
.RTI => self.RTI(),
|
||||
.RTS => self.RTS(),
|
||||
.SBC => self.SBC(),
|
||||
.SEC => self.SEC(),
|
||||
.SED => self.SED(),
|
||||
.SEI => self.SEI(),
|
||||
.STA => self.STA(),
|
||||
.STX => self.STX(),
|
||||
.STY => self.STY(),
|
||||
.TAX => self.TAX(),
|
||||
.TAY => self.TAY(),
|
||||
.TSX => self.TSX(),
|
||||
.TXA => self.TXA(),
|
||||
.TXS => self.TXS(),
|
||||
.TYA => self.TYA(),
|
||||
else => 255,
|
||||
};
|
||||
}
|
||||
|
||||
fn ADC(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn AND(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn ASL(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BCC(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BCS(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BEQ(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BIT(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BMI(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BNE(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BPL(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BRK(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BVC(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn BVS(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn CLC(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn CLD(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn CLI(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn CLV(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn CMP(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn CPX(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn CPY(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn DEC(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn DEX(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn DEY(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn EOR(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn INC(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn INX(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn INY(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn JMP(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn JSR(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn LDA(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn LDX(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn LDY(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn LSR(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn NOP(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn ORA(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn PHA(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn PHP(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn PLA(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn PLP(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn ROL(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn ROR(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn RTI(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn RTS(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn SBC(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn SEC(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn SED(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn SEI(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn STA(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn STX(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn STY(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn TAX(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn TAY(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn TSX(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn TXA(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn TXS(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
|
||||
fn TYA(self: *Self) u8 {
|
||||
_ = self;
|
||||
}
|
||||
29
src/bus.zig
Normal file
29
src/bus.zig
Normal file
|
|
@ -0,0 +1,29 @@
|
|||
const std = @import("std");
|
||||
const Mos6502 = @import("6502.zig");
|
||||
|
||||
/// CPU Device on Bus
|
||||
cpu: Mos6502 = undefined,
|
||||
|
||||
/// Memory (RAM) 64kb or 0xFFFF
|
||||
ram: [0xFFFF]u8 = undefined,
|
||||
|
||||
const Self = @This();
|
||||
|
||||
pub fn init(self: *Self) !void {
|
||||
self.cpu.bus = self;
|
||||
try self.cpu.init();
|
||||
}
|
||||
|
||||
pub fn deinit(self: *Self) void {
|
||||
self.cpu.deinit();
|
||||
}
|
||||
|
||||
pub fn write(self: *Self, addr: u16, data: u8) void {
|
||||
if (addr >= 0x0000 and addr <= 0xFFFF)
|
||||
self.ram[addr] = data;
|
||||
}
|
||||
|
||||
pub fn read(self: *Self, addr: u16, readOnly: bool) u8 {
|
||||
_ = readOnly;
|
||||
return if (addr >= 0x0000 and addr <= 0xFFFF) self.ram[addr] else 0xAA;
|
||||
}
|
||||
18
src/main.zig
18
src/main.zig
|
|
@ -1,8 +1,9 @@
|
|||
const std = @import("std");
|
||||
const sdl = @cImport(@cInclude("SDL.h"));
|
||||
const System = @import("bus.zig");
|
||||
|
||||
var window: ?*sdl.SDL_Window = null;
|
||||
var renderer : ?*sdl.SDL_Renderer = null;
|
||||
var renderer: ?*sdl.SDL_Renderer = null;
|
||||
|
||||
pub fn init() !void {
|
||||
std.debug.print("ZeNES Starting!\n", .{});
|
||||
|
|
@ -10,7 +11,7 @@ pub fn init() !void {
|
|||
if (sdl.SDL_Init(sdl.SDL_INIT_EVERYTHING) < 0) {
|
||||
@panic("SDL Initialization Failed!");
|
||||
}
|
||||
|
||||
|
||||
window = sdl.SDL_CreateWindow("ZeNES", sdl.SDL_WINDOWPOS_CENTERED, sdl.SDL_WINDOWPOS_CENTERED, 768, 720, 0);
|
||||
if (window == null) {
|
||||
@panic("SDL Window Creation Failed!");
|
||||
|
|
@ -18,7 +19,7 @@ pub fn init() !void {
|
|||
|
||||
renderer = sdl.SDL_CreateRenderer(window, -1, 0);
|
||||
|
||||
if(renderer == null) {
|
||||
if (renderer == null) {
|
||||
var err = sdl.SDL_GetError();
|
||||
std.debug.print("{s}\n", .{err});
|
||||
|
||||
|
|
@ -38,21 +39,20 @@ pub fn main() !void {
|
|||
try init();
|
||||
defer deinit();
|
||||
|
||||
var sys: System = undefined;
|
||||
try sys.init();
|
||||
|
||||
var keep_open = true;
|
||||
while (keep_open) {
|
||||
var e: sdl.SDL_Event = undefined;
|
||||
while (sdl.SDL_PollEvent(&e) > 0) {
|
||||
switch (e.type) {
|
||||
sdl.SDL_QUIT => keep_open = false,
|
||||
else => {}
|
||||
else => {},
|
||||
}
|
||||
}
|
||||
|
||||
_ = sdl.SDL_RenderClear(renderer);
|
||||
|
||||
_ = sdl.SDL_RenderPresent(renderer);
|
||||
|
||||
//Wait 60hz
|
||||
std.time.sleep(16 * 1000 * 1000);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in a new issue