def run(self, program):
'''Execute list of instructions'''
end = program[0] # First opcode is length
self.memory = [0] * program[1] # Second opcode is memory size requirement
self.pc = 2
while self.pc < end and program[self.pc] != opset.HALT:
instruction = program[self.pc]
self.pc += 1
if opset.nullary(instruction):
self.debug("%02d %s", self.pc, opset.byte2name[instruction])
self.nullary[instruction]()
elif opset.unary(instruction):
argument = program[self.pc]
self.pc += 1
self.debug("%02d %s %s", self.pc, opset.byte2name[instruction], argument)
self.unary[instruction - opset.LIT](argument)
def findsymbols(self, program):
"""Find labels and variables and build symboltable"""
symbols = {opset.LABEL: {}, opset.MEM: {}}
pc = addr = 0
end = len(program)
newprogram = [0, 0]
self.debug("Finding labels and variables")
while pc < end:
instruction = program[pc]
pc += 1
if opset.nullary(instruction):
newprogram.append(instruction)
elif opset.unary(instruction):
argument = program[pc]
pc += 1
if instruction in (opset.LABEL, opset.MEM):
if argument in symbols[instruction]:
raise Exception(
"Cannot declare symbol more than once: %s %s" % (opset.byte2name[instruction], argumet)
)
if instruction == opset.LABEL:
value = len(newprogram)
else:
value = addr
addr += 1
self.debug("Symbol - %s %s -> %s", opset.byte2name[instruction], argument, value)
symbols[instruction][argument] = value
else:
newprogram.append(instruction)
newprogram.append(argument)
# First instruction is length
newprogram[0] = len(newprogram)
# Second instruction is memory requirement
newprogram[1] = addr
return newprogram, symbols