def executeInstruction(
node: nodes.InstructionNode, state: programState.ProgramState,
fileName: str,
lines: List[str]) -> Tuple[programState.ProgramState, bool]:
if isinstance(node, nodes.InstructionNode):
# Execute the instruction
state, err = node.function(state)
# Exception handling
if err is not None:
if isinstance(err, programState.RunError):
if err.errorType == programState.RunError.ErrorType.Error:
print(generateStacktrace(state, err, fileName, lines))
return state, False
elif err.errorType == programState.RunError.ErrorType.Warning:
print(generateStacktrace(state, err, fileName, lines))
elif isinstance(err, programState.StopProgram):
return state, False
# Set a flag in the ProgramState when a subroutine returned. This way the stacktrace generator knows to not print a stacktrace element for the link register
pc = state.getReg("PC")
if pc == state.getReg("LR"):
state.hasReturned = True
# increment the program counter
state.setReg("PC", pc + 4)
return state, True
else:
if isinstance(node, programState.RunError):
print(generateStacktrace(state, node, fileName, lines))
return state, False
def branchToLabel(state: programState.ProgramState, label: str) -> Tuple[programState.ProgramState, Union[programState.RunError, None]]:
# Save return address in LR
state.setReg("LR", state.getReg("PC"))
address: Union[int, programState.RunError] = state.getLabelAddress(label)
if isinstance(address, programState.RunError):
return state, programState.RunError(f"Unknown startup label: {label}", programState.RunError.ErrorType.Error)
else:
# Subtract 4 because we will add 4 to the address later in the run loop and we need to start at address and not address+4
state.setReg("PC", address - 4)
state.hasReturned = False
return state, None
def branchTo(
state: programState.ProgramState
) -> Tuple[programState.ProgramState, Union[programState.RunError,
None]]:
if link:
# Save return address in LR
state.setReg("LR", state.getReg("PC")[0])
address, err = state.getReg(label.contents)
# Subtract 4 because we will add 4 to the address later in the run loop and we need to start at address and not address+4
state.setReg("PC", address - 4)
state.hasReturned = False
return state, err
def branchTo(
state: programState.ProgramState
) -> Tuple[programState.ProgramState, Union[programState.RunError,
None]]:
# Save return address in LR
pc, _ = state.getReg("PC")
state.setReg("LR", pc)
address: Union[int, programState.RunError] = state.getLabelAddress(
label.contents)
if isinstance(address, programState.RunError):
return state, address
else:
# Subtract 4 because we will add 4 to the address later in the run loop and we need to start at address and not address+4
state.setReg("PC", address - 4)
state.hasReturned = False
return state, None