def _load_from_memory(
self,
vm: Chip8VirtualMachine,
max_register: int,
read_src: int = 0xA00,
value_start: int = 128
) -> None:
"""
Helper function that executes a bulk register save operation.
Will write value_start +0, ... value_start + max_register to
the first max_register registers.
Then runs FX55, with max_register as X.
:param vm: vm object to write to
:param max_register: the highest register that will be saved
:param value_start: what the start of the written values will be
:return:
"""
# set up the memory with values to read into registers
for register_index in range(0, max_register + 1):
vm.memory[read_src + register_index] = 128 + register_index
# set up where the registers will be stored to
vm.i_register = read_src
load_and_execute_instruction(
vm, 0xF065, x=max_register
)
def _write_values_to_memory(
self,
vm: Chip8VirtualMachine,
max_register: int,
write_dest: int = 0xA00,
value_start: int = 128
) -> None:
"""
Helper function that executes a bulk register save operation.
Will write value_start +0, ... value_start + max_register to
the first max_register registers.
Then runs FX55, with max_register as X.
:param vm: vm object to write to
:param max_register: the highest register that will be saved
:param value_start: what the start of the written values will be
:return:
"""
# set up the registers with unique values that can be checked
# for correct write order in memory.
for index in range(0, max_register + 1):
vm.v_registers[index] = value_start + index
# set up where the registers will be stored to
vm.i_register = write_dest
load_and_execute_instruction(
vm, 0xF055, x=max_register
)