349 lines
10 KiB
Python
349 lines
10 KiB
Python
#!/usr/bin/python3
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from enum import Enum
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class MalformedArgument(Exception):
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pass
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def word_2c(w):
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""" Negate a non-negative integer using 32 bit two's compliment.
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:param w: An integer in two's compliment. A non-negative Python
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integer will work.
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:return: The negation of the integer stored as a two's compliment
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integer.
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"""
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return (~w + 1) & 0xFFFFFFFF
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def ti(w):
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""" Explicitly transform integer into two's compliment representation.
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:param w: A python integer.
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:return: The integer in two's compliment.
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"""
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return w if w >= 0 else word_wc(-w)
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def from_2c(w):
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""" Turn two's compliment word into Python integer.
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:param w: An integer in 32 bit twos compliment.
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:return: The integer as a proper Python string.
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"""
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if (w >> 31) & 1 == 0:
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return w
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return -word_2c(w)
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class Argument:
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""" Class of arguments. Not used directly: It is used to store
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intermediate information during the assembly process. """
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def __init__(self, argtype, val, sign=False):
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""" Initialize an argument.
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:param argtype: Type of the argument (instance of ArgType).
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:param val: Python integer value of the argument.
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:param sign: If the argument should be treated as signed.
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Otherwise, the integer will be interpreted in execution
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as an unsigned integer.
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"""
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self.at = argtype
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self.sign = sign
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self.val = val
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def __str__(self):
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return f'({self.at}, {self.sign}, {self.val})'
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def high_bits(self):
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""" Returns the high bits that the argument would have
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in the opcode. """
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return int(self.sign) << 1 | (self.at == ArgType.REG)
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class ArgType(Enum):
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""" Class denoting the type of an argument to an instruction. """
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IMM = 1
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""" Immediate values are ones that must be numbers (positive or negative). """
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REG = 2
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""" Type of registers. """
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VAL = 3
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""" Type that denotes either immediate values or registers. """
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LAB = 4
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""" Type of labels. """
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def gettype(s):
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""" Parses the type of the argument represented as a string
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and returns a tuple with the first the first element being
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the type and the second element being the integer value of
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the argument.
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Valid parameters are:
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* `r` followed by a nonnegative integer (register)
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* `l` followed by a nonnegative integer (label)
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* any integer (immediate value)
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:param s: String representing the argument.
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:return: The Argument object representing the argument.
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:raises MalformedArgument:
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"""
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if s.isnumeric():
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return Argument(ArgType.IMM, int(s))
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elif s[0] == "-" and s[1:].isnumeric():
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return Argument(ArgType.IMM, word_2c(int(s[1:])), True)
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elif s[0] == 'r' and s[1:].isnumeric():
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return Argument(ArgType.REG, int(s[1:]))
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elif s[0] == 'l' and s[1:].isnumeric():
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return Argument(ArgType.LAB, int(s[1:]))
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else:
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raise MalformedArgument(s)
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def typecheck(self, s):
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""" Parses the type of the string and returns it if it fits
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the type of the enum value.
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:param s: String argument representing an argument.
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:return: The Argument class containing the object, or None
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if the string does not fit the type of self. """
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t = ArgType.gettype(s)
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if self == ArgType.VAL:
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if t.at == ArgType.REG or t.at == ArgType.IMM:
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return t
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else:
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return None
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elif t.at == self:
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return t
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else:
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return None
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class OpcodeException(Exception):
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pass
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class TypecheckLenException(Exception):
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""" Exception thrown when arguments to an instruction are of the
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incorrect length. """
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def __init__(self, opcode, insargs, argtypelen):
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self.opcode = opcode
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self.insargs = insargs
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self.argtypelen = argtypelen
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def __str__(self):
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return f'''\
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arguments {self.insargs} to opcode {self.opcode} not of length {self.argtypelen}\
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'''
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class TypecheckException(Exception):
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""" Exception thrown when an argument to an instruction are of the
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incorrect type. """
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def __init__(self, argtype, sarg, i, opcode):
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self.argtype = argtype
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self.sarg = sarg
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self.i = i
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self.opcode = opcode
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def __str__(self):
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return f'''\
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opcode {self.opcode} has invalid value {self.sarg}
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(expected {self.argtype} in position {self.i})\
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'''
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class Instruction(Enum):
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""" Class of microcode instructions. The first number is the opcode
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and the suceeding values are the types of each of the
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arguments. The first argument is the opcode and the second
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argument is what function is used to compile the instruction
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(some instructions are actually versions of other instructions). """
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NOP = 0, "_render_default"
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PUSH = 1, "_render_default", ArgType.VAL
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POP = 2, "_render_default", ArgType.REG
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ADD = 3, "_render_default", ArgType.REG, ArgType.VAL, ArgType.VAL
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MOV = "ADD", "_render_mov", ArgType.REG, ArgType.VAL
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MUL = 4, "_render_default", ArgType.REG, ArgType.VAL, ArgType.VAL
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DIV = 5, "_render_default", ArgType.REG, ArgType.VAL, ArgType.VAL
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SDIV = "DIV", "_render_change_args", ArgType.REG, ArgType.VAL, ArgType.VAL
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SYS = 6, "_render_default", ArgType.VAL
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CLB = 7, "_render_default", ArgType.LAB
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JL = 8, "_render_default", ArgType.LAB, ArgType.VAL, ArgType.VAL
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JLS = "JL", "_render_change_args", ArgType.LAB, ArgType.VAL, ArgType.VAL
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JLE = 9, "_render_default", ArgType.LAB, ArgType.VAL, ArgType.VAL
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JLES = "JLE", "_render_change_args", ArgType.LAB, ArgType.VAL, ArgType.VAL
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JE = 10, "_render_default", ArgType.LAB, ArgType.VAL, ArgType.VAL
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J = "JE", "_render_j", ArgType.LAB
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JNE = 11, "_render_default", ArgType.LAB, ArgType.VAL, ArgType.VAL
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def __int__(self):
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""" Returns the opcode associated with the Instruction.
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If it is a virtual instruction, it will resolve the string
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name of the opcode and return its opcode. """
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if type(self.opcode) is int:
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return self.opcode
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return int(Instruction[self.opcode])
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def __init__(self, opcode, renderfun, *args):
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""" Initialize an Instruction. Do not call this function: it is
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used to make enum values. To add a new instruction, modify
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the Instruction enum.
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This function sometimes takes string arguments because
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certain values may not be loaded until later.
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:param opcode: Opcode of the instruction, or a string
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containing the case-sensitive name of the instruction from
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which this instruction derives from.
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:param renderfun: a string with the name of a function
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in the class that returns the instruction opcode.
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:param *args: Type of each argument to the instruction.
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The amount of arguments denotes the amount of instructions.
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"""
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if type(opcode) is int and (opcode > 0x7F or opcode < 0):
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raise OpcodeException(opcode)
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self.opcode = opcode
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self.argtypes = args
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self.render = getattr(self, renderfun)
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def typecheck(self, sargs):
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""" Pass arguments to the instruction and check if the
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arguments are correct.
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:param sargs: List of arguments to the instruction
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as strings.
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:return: List of arguments (as Argument objects).
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:raises TypeCheckException:
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:raises TypecheckLenException:
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"""
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rargs = []
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if len(sargs) != len(self.argtypes):
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raise TypecheckLenException(self.opcode, sargs,
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len(self.argtypes))
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for i in range(0, len(sargs)):
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t = self.argtypes[i].typecheck(sargs[i])
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if t is None:
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raise TypecheckException(self.argtypes[i],
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sargs[i],
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i, self.opcode)
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rargs.append(t)
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return rargs
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def _render_mov(self, args):
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args = [args[0], args[1], Argument(ArgType.IMM, 0)]
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return Instruction[self.opcode].render(args)
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def _render_j(self, args):
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args = [args[0], Argument(ArgType.IMM, 0),
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Argument(ArgType.IMM, 0)]
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return Instruction[self.opcode].render(args)
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def _render_change_args(self, args):
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for i in range(0,len(args)):
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if args[i].at != ArgType.LAB:
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args[i].sign = True
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return Instruction[self.opcode].render(args)
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def _render_default(self, args):
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b = bytes([self.opcode])
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for a in args:
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l = 2 if a.val < 0x80 else None
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bex = encode_pseudo_utf8(a.val, a.high_bits(), l)
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b = b + bex
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return b + bytes([0])
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encoding_types = {
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# start mask B
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2: (0x7F, 0xC0, 7),
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3: (0xFFF, 0xE0, 12),
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4: (0x1FFFF, 0xF0, 17),
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5: (0x3FFFFF, 0xF8, 22),
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6: (0x7FFFFFF, 0xFC, 27),
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7: (0xFFFFFFFF, 0xFE, 32),
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# B : Total number of bits excluding high bits
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}
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class InvalidNumberException(Exception):
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pass
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class InvalidLengthException(Exception):
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pass
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def encode_pseudo_utf8(n, high_bits, to):
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if n < 0:
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raise InvalidNumberException(n)
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if to is None or to < 0:
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for k in sorted(encoding_types):
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if n <= encoding_types[k][0]:
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to = k
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break
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if to is None:
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raise InvalidNumberException(n)
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if to > 8 or to < 0:
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raise InvalidLengthException(to)
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elif to == 1:
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if n < 0x80:
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return bytes([n])
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else:
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raise InvalidNumberException(n,to)
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(maxval, start_byte, n_tot) = encoding_types[to]
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if n > maxval or high_bits > 15:
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raise InvalidNumberException(n, high_bits)
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n = n | (high_bits << n_tot)
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all_bytes = []
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for i in range(0, to - 1):
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all_bytes.append(0x80 | (n & 0x3F))
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n >>= 6
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all_bytes.append(start_byte | n)
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return bytes(reversed(all_bytes))
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class RangeCheckException(Exception):
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pass
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class Line:
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def __init__(self, ins, args):
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self.ins = ins
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self.args = args
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def check_line(self, lablen, reglen):
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for a in self.args:
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if a.at == ArgType.REG:
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if a.val < 0 or a.val >= reglen:
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raise RangeCheckException(a.at,
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a.val,
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reglen)
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elif a.at == ArgType.LAB:
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if a.val < 0 or a.val >= lablen:
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raise RangeCheckException(a.at,
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a.val,
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reglen)
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def __call__(self):
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return self.ins.render(self.args)
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class InstructionNotFoundException(Exception):
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pass
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class Program:
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def asm_push_line(self, ins, args):
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l = Line(ins, args)
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l.check_line(self.lablen, self.reglen)
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self.asm.append(l)
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def parse_asm_line(self, line):
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line = line.split()
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line[0] = line[0].casefold()
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try:
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# TODO: is there no better way to do this in Python?
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ins = Instruction[line[0].upper()]
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except Exception as e:
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raise InstructionNotFoundException(line[0])
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args_w_type = ins.typecheck(line[1:])
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self.asm_push_line(ins, args_w_type)
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def parse_lines(self, lines):
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for l in lines:
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self.parse_asm_line(l)
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def __call__(self):
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b = bytes()
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for line in self.asm:
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b = b + line()
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return b
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def __init__(self, lablen=16, reglen=16):
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self.asm = []
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self.lablen = lablen
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self.reglen = reglen
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