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@fr0zn fr0zn/vermu1-emulator.py Secret
Last active Sep 7, 2019

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r = open('level1','rb').read()
b = bytearray(r)
mem = bytearray([0] * 0x10000)
mem[0:len(b)] = b[0:len(b)]
pc = 0
stack = []
# def split_n(line,n=4):
# return [line[i:i+n] for i in range(0, len(line), n)]
def tohex(val, nbits=32):
return hex((val + (1 << nbits)) % (1 << nbits))
def parse_instruction(b):
global pc
if b[pc] == 0:
print "NOP"
pc += 1
elif b[pc] == 0x10:
val = int(str(b[pc+1:pc+1+4]).encode('hex'), 16)
print "PUSH " + hex(val)
stack.append(val)
pc += 5
elif b[pc] == 0x20:
addr = stack.pop()
value = stack.pop()
print "STORE @ {} -> {}".format(hex(addr), hex(value))
mem[addr] = value
mem[addr+1] = value >> 8
mem[addr+2] = value >> 16
mem[addr+3] = value >> 24
pc += 1
elif b[pc] == 0x21:
addr = stack.pop()
# dst = stack.pop()
val = 0
val = mem[addr]
val += mem[addr+1] << 8
val += mem[addr+2] << 16
val += mem[addr+3] << 24
print "PUSH [{}] -> {}".format(hex(addr), hex(val))
stack.append(val)
pc += 1
elif b[pc] == 0x30:
n1 = stack.pop()
n2 = stack.pop()
stack.append(n1 + n2)
print "ADD {} + {}".format(hex(n1), hex(n2))
pc += 1
elif b[pc] == 0x31:
n1 = stack.pop()
n2 = stack.pop()
stack.append(n1 ^ n2)
print "XOR {} ^ {} -> {}".format(tohex(n1), tohex(n2), tohex(n1 ^ n2))
pc += 1
elif b[pc] == 0x32:
n1 = stack.pop()
n2 = stack.pop()
if n1 == n2:
r = 0
elif n1 <= n2:
r = -1
else:
r = 1
stack.append(r)
print "CMP {} and {} -> {}".format(tohex(n1), tohex(n2), r )
pc += 1
elif b[pc] == 0x33:
n1 = stack.pop()
n2 = stack.pop()
stack.append(n1 * n2)
print "MULTIPLY {} * {}".format(n1, n2)
pc += 1
elif b[pc] == 0x38:
n1 = stack.pop()
stack.append(~n1)
print "NEGATE {} -> {}".format(hex(n1), tohex(~n1))
pc += 1
elif b[pc] == 0x41:
addr = stack.pop()
print "JMP @ {}".format(hex(addr))
pc = addr
elif b[pc] == 0x42:
addr = stack.pop()
result = stack.pop()
print "JMP CONDITIONAL {} to addr {}".format(result, hex(addr))
if result != 0:
pc += 1
else:
pc = addr
elif b[pc] == 0x50:
# one of the ops only 2 possible in level1
op = stack.pop()
if op == 0:
n = stack.pop()
n2 = stack.pop()
print "READING @ {} ({} bytes) ".format(hex(n2), n)
r = raw_input("READING {} bytes: ".format(n))
mem[n2:n2+n] = r[:n]
else:
print "UNK OP"
pc += 1
else:
print "UNK " + hex(b[pc])
pc += 1
# while pc <= len(b):
while pc <= 230: #and mem[0x1000] != 1:
parse_instruction(b)
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