match= {
    reg: "(io|sp|ipage|dpage|stackptr|gp[0-3])",
    imm8: "~?#(0b[0-1]{1,8}|(0x)?[0-9]{1,3})",
    label: "[A-z][A-z0-9]*",
    flags: "(INPUT|OVERFLOW|NEGATIVE|CARRY|ZERO)"
  }
instructions = {
  match: match,
  registers:[
    "io",
    "stackptr",
    "dpage",
    "ipage",
    "gp0",
    "gp1",
    "gp2",
    "gp3"
  ],
  flags:[
    "INPUT",
    "OVERFLOW",
    "NEGATIVE",
    "CARRY",
    "ZERO"
  ].reverse(),
  arg_patterns:[
    [
      { pattern: [ match.reg, match.reg ], mode: 0 },
      { pattern: [ match.reg, match.imm8 ], mode: 1 },
    ],
    [
      { pattern: [ match.reg ], mode: 0 }
    ],
    [
      { pattern: [ match.reg ], mode: 1 }

    ],
    [
      { pattern: [ match.flags, match.reg ], mode: 0 },
      { pattern: [ match.flags, match.imm8 ], mode: 1 },
    ],
    [
      { pattern: [ match.reg ], mode: 0 },
      { pattern: [ match.imm8 ], mode: 1 },
    ],
    [
      { pattern: [ ], mode: 0 }
    ],
    [
      { pattern: [ ], mode: 1 }
    ]
  ],
  opcodes:[
    {
      opcode: 0b0000,
      mnemonic:"add",
      patterns: 0,
      description: "Adds the immediate data, or the contents of the register given as the second operand to the register given as first operand."
    },
    {
      opcode: 0b0001,
      mnemonic:"sub",
      patterns: 0,
      description: "Subtracts the immediate data, or the contents of the register given as the third operand to the register given as the first operand."
    },
    {
      opcode:0b0010,
      mnemonic: "adc",
      patterns: 0,
      description: "Adds the two operands plus the carry flag, stores in the first operand register."
    },
    {
      opcode:0b0011,
      mnemonic:"subb",
      patterns:0,
      description: "Subtracts the second operand plus the carry flag from the first operand."
    },
    {
      opcode:0b0100,
      mnemonic:"nand",
      patterns:0,
      description:"Performs logical NAND on the two operands; stores in first operand register."
    },
    {
      opcode:0b0101,
      mnemonic: "xor",
      patterns:0,
      description:"Performs logical XOR on the two operands; stores in first operand register."
    },
    {
      opcode:0b0110,
      mnemonic:"sll",
      patterns:0,
      description:"Shifts bits in the first operand register left by the amount specified in the second operand."
    },
    {
      opcode:0b0111,
      mnemonic:"srl",
      patterns:0,
      description:"Shifts bits in the first operand register right by the amount specified in the second operand."
    },
    {
      opcode:0b1000,
      mnemonic:"mov",
      patterns:0,
      description: "Copies the register or data in the second operand into the first operand register."
    },
    {
      opcode:0b1001,
      mnemonic:"ldb",
      patterns:0,
      description:"Loads the byte into the first operand register at the address specified in the second operand."
    },
    {
      opcode:0b1010,
      mnemonic:"stb",
      patterns:0,
      description:"Stores the contents of the first operand register into the address specified in the second operand."
    },
    {
      opcode:0b1011,
      mnemonic:"nop",
      patterns:5,
      description:"performs no operation."
    },
    {
      opcode:0b1100,
      mnemonic:"bflag",
      patterns:0,
      description: "Branches to the specified memory address if the specified flag bit is set."
    },
    {
      opcode:0b1101,
      mnemonic:"bnoflag",
      patterns:0,
      description: "Branches to the specified memory address if the specified flag bit is NOT set."
    },

    {
      opcode:0b1110,
      mnemonic:"jmp",
      patterns:4,
      description:"Branches unconditionally to the specified memory address."
    },
    {
      opcode:0b1111,
      mnemonic:"hlt",
      patterns:5,
      description:"Terminates execution."
    }
  ]
}