S_Format.py

class MyException(Exception):
    pass
mnemonic = {

    'sb': {'opcode': '0100011', 'funct3': '000'},
    'sh': {'opcode': '0100011', 'funct3': '001'},
    'sw': {'opcode': '0100011', 'funct3': '010'},
    'sd': {'opcode': '0100011', 'funct3': '011'},
}

def S_Format(instruction):
    instruction = instruction.replace(')', '')
    instruction = instruction.replace('(', ',')
    instruction = instruction.replace(' ', ',')
    instruction_arr = instruction.split(',')
    while '' in instruction_arr:
        instruction_arr.remove('')
    (instruction_arr[2], instruction_arr[3]) = (instruction_arr[3], instruction_arr[2])
    machine_code = []
    ###################
    if(len(instruction_arr)!=4):
        raise MyException("Expected three arguements!")
    try:
        int(instruction_arr[3])
    except:
        raise MyException("Offset Value must be an Integer!")
    if int(instruction_arr[3]) >= 2**11 or int(instruction_arr[3]) < -(2**11):
        raise MyException("Immediate value out of bounds!")
    ##################
    if(int(instruction_arr[3]))>=0:
        immediate=bin(int(instruction_arr[3])).replace("0b","").rjust(12,'0')
    else:
        immediate=bin(2**12+int(instruction_arr[3])).replace("0b","").rjust(12,'0')

    imm1=str(immediate)[0:7]
    imm2= str(immediate)[7:12]
    machine_code.append(imm1)
    if 'x' not in instruction_arr[1] or 'x' not in instruction_arr[2]:
        raise MyException("Enter register numbers in correct format")
    instruction_arr[1] = instruction_arr[1].replace('x', '')
    instruction_arr[2] = instruction_arr[2].replace('x', '')
    #########################
    try:
        int(instruction_arr[1])
        int(instruction_arr[2])
    except:
        raise MyException("Register number must be an Integer!")
    if(int(instruction_arr[1])>31 or int(instruction_arr[2])>31):
        raise MyException("Register number must be between 0 and 31, both inclusive.")
    #########################
    machine_code.append(bin(int(instruction_arr[1])).replace("0b", "").rjust(5, '0'))
    machine_code.append(bin(int(instruction_arr[2])).replace("0b", "").rjust(5, '0'))
    machine_code.append(mnemonic[instruction_arr[0]]['funct3'])
    machine_code.append(imm2)
    machine_code.append(mnemonic[instruction_arr[0]]['opcode'])
    machine_hex="{:08x}".format(int(''.join(machine_code),2))
    return "0x"+machine_hex