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infernal-interpreter/Emulator.py

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4.4 KiB
Python
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import re
import Junk
from opcodes import OPCODES
REGISTERS=["%rax", "%rbx", "%rcx", "%rdx", "%rsp", "%rbp", "%rsi", "%rdi",
"%r8", "%r9", "%r10", "%r11", "%r12", "%r13", "%r14", "%r15"]
class CodeParseException (BaseException):
def __init__ (self, line_nr, string):
self.line_nr = line_nr
self.string = string
class InternalExecutionException (BaseException):
pass
class Emulator:
def __init__ (self, source_text, max_stack_size=1000):
self.source = source_text
self.registers = {}
for reg_name in REGISTERS:
self.registers[reg_name] = Junk.Junk()
self.stack = {}
for i in range(max_stack_size):
self.stack[i] = Junk.Junk()
self.code = []
self.labels = {}
self.changes = {}
self.status = {'i':True}
self.last_sp = 0
self.max_stack_size = 0
index = 0
for line in iter(source_text.splitlines()):
index = self.processSourceLine(line, index)
def setStack (self, *stack_list, **kwargs):
"""
Sets various stack elements, starting from 0 and going up.
Automatically sets rsp. This can be disabled by passing set_rsp=False.
"""
i = len(self.stack)
for element in stack_list:
i -= 1
self.stack[i] = element
self.setRegs(rsp=i)
self.last_sp = i-1
def setRegs (self, **reg_dict):
for reg_name, reg_val in reg_dict.iteritems():
assert(reg_name[0] != '%')
self.registers["%"+reg_name] = reg_val
def getVal (self, val_text):
if val_text[0] == "$":
return int(val_text[1:])
elif val_text[0] == "%":
return self.registers[val_text]
else:
raise ValueError('{} is not an usable value name'.format(val_text))
def compareVal (self, valT1, valT2):
val1 = self.getVal(valT2)
val2 = self.getVal(valT1)
if isinstance(val1,Junk.Junk) or isinstance(val2,Junk.Junk):
self.status["i"] = (True,)
return
self.status["g"] = val1>val2
self.status["l"] = val1<val2
self.status["e"] = val1==val2
self.status["i"] = False
def changedRegisters (self, *args):
for reg, val in args:
self.changes[reg] = val
def processSourceLine(self, line_text, index):
tokens = re.findall(r'[^\s,]+', line_text)
if len(tokens) <= 0 or tokens[0][0] == '#':
return index
if tokens[0][-1] == ':':
self.labels[tokens[0][:-1]] = index
tokens = tokens[1:]
for i in range(len(tokens)):
if tokens[i][0] == "#":
tokens = tokens[:i]
break
self.code.append(tokens)
return index + 1
def regState (self, reg_name):
if reg_name in self.changes:
return self.changes[reg_name]
else:
return "none"
def getLineSignature (self, line_nr):
return [ "\\"+token if token[0]=="$" or token[0]=="%" else token for token in self.code[line_nr] ]
def pushToStack (self, new_element):
self.registers['%rsp'] -= 1
self.stack[self.registers['%rsp']] = new_element
self.changedRegisters(('%rsp',"change"), ("m"+str(self.registers['%rsp']),"insert"))
self.max_stack_size = max(self.registers['%rsp'], self.max_stack_size)
def popFromStack (self):
temp = self.stack[self.registers['%rsp']]
self.changedRegisters(('%rsp',"change"),("m"+str(self.registers['%rsp']),"remove"))
self.registers['%rsp'] += 1
return temp
def jump (self, label, cond_op="or", **conditions):
if len(conditions)>0 and self.status["i"]:
raise Junk.JunkComparisonException(*self.status['i'])
and_, or_ = True, False
for cnd_name, cnd_val in conditions.iteritems():
if self.status[cnd_name] == cnd_val:
or_ = True
else:
and_ = False
if or_ if cond_op=="or" else and_:
self.registers['%rip'] = self.labels[label]
return True
else:
return False
def iterate (self):
old_rip = self.registers['%rip']
self.last_sp = self.registers['%rsp']
if self.registers['%rip'] >= len(self.code) or isinstance(self.registers['%rip'], Junk.Junk):
return None
if not isinstance(self.registers['%rip'], (int, long)):
raise InternalExecutionException("Register %rip should be integer, but was "+str(self.registers['%rip']))
instruct = self.code[self.registers['%rip']]
opcode = instruct[0]
self.changes = {}
OPCODES[opcode](self, *instruct[1:])
if self.registers['%rip'] == old_rip:
self.registers['%rip'] += 1
else:
self.changedRegisters(('%rip',"jump"))
return old_rip
def __iter__(self):
return self
def next(self):
output = self.iterate()
if output is None:
raise StopIteration()
else:
return output
def getUsedRegisters (self):
return [reg_name for reg_name, reg_val in self.registers.iteritems() if not isinstance(reg_val, Junk.Junk)]