from instruction_table import untabulate_instructions_sh2

instruction_table = untabulate_instructions_sh2()

def match_instruction(n, ins):
    return (n & ins.code.mask_bits) == ins.code.code_bits

def decode_instruction(n):
    global instruction_table

    for ins in instruction_table:
        if match_instruction(n, ins):
            return ins
    return None

def decode_variables(n, ins):
    operands = ins.code.operands
    return [
        (n >> operands[variable].lsb) & ((1 << operands[variable].length) - 1)
        for variable in ins.variables
    ]