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#!/usr/bin/python
class Caretaker:
def __init__(self):
self.objects=dict() # Create empty objects pool
# Add registers to pool
for reg in ["MAR","MDR", "PC", "MBR", "SP","LV","CPP","TOS","OPC","H"]:
self.objects[reg]=0
self.objects["RAM"]=None
def __getitem__(self,key):
if key=="MBRU": # If we ask for unsigned
return(abs(self.objects["MBR"]))
elif key== "MBR":
if (self.objects[key]>>7)==1: # If it a negative number (2 complement)
return(-((self.objects[key]-1)^0xFF)) # transforme bin negative number to python negative number
else:
return(self.objects[key])
return(self.objects[key])
def __setitem__(self,key,value):
if key!="RAM":
if value > (2**32) and key!="MBR" and key!="MBRU": # Check value fit in word
print("Warning word overflow: value {} on register {}".format(value,key))
value=value%(2**32) # Force to fit in word
elif value > (2**8) and key=="MBR" and key=="MBRU": # Check value fit in byte
print("Warning byte overflow: value {} on register {}".format(value,key))
value=value%256 # Force to fit in byte
self.objects[key]=value
def items(self):
return(self.objects.items())
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