def execute(self, processor, memory, pc):
result, half_carry, _ = bitwise_sub(0, processor.main_registers['a'])
set_condition = processor.set_condition
set_condition('s', to_signed(result) < 0)
set_condition('z', result == 0)
set_condition('h', half_carry)
set_condition('p', processor.main_registers['a'] == 0x80)
set_condition('n', True)
set_condition('c', processor.main_registers['a'] != 0x00)
processor.main_registers['a'] = result
return 8, False, pc
def execute(self, processor, memory, pc):
result, half_carry, _ = bitwise_sub(0, processor.main_registers['a'])
set_condition = processor.set_condition
set_condition('s', to_signed(result) < 0)
set_condition('z', result == 0)
set_condition('h', half_carry)
set_condition('p', processor.main_registers['a'] == 0x80)
set_condition('n', True)
set_condition('c', processor.main_registers['a'] != 0x00)
processor.main_registers['a'] = result
return 8, False, pc
def _cp_value(processor, value, carry):
signed_a = to_signed(processor.main_registers['a'])
if carry:
value = (value + 1) & 0xff
result, half_carry, full_carry = bitwise_sub(processor.main_registers['a'], value)
signed_result = to_signed(result)
set_condition = processor.set_condition
set_condition('s', signed_result < 0)
set_condition('z', result == 0)
set_condition('h', half_carry)
set_condition('p', (signed_a < 0) != (signed_result < 0))
set_condition('n', True)
set_condition('c', full_carry)
def _cp_value(processor, value, carry):
signed_a = to_signed(processor.main_registers['a'])
if carry:
value = (value + 1) & 0xff
result, half_carry, full_carry = bitwise_sub(processor.main_registers['a'],
value)
signed_result = to_signed(result)
set_condition = processor.set_condition
set_condition('s', signed_result < 0)
set_condition('z', result == 0)
set_condition('h', half_carry)
set_condition('p', (signed_a < 0) != (signed_result < 0))
set_condition('n', True)
set_condition('c', full_carry)
def _block_compare(processor, memory, increment):
src_addr = processor.get_16bit_reg('hl')
value_to_compare = memory[src_addr]
result, half_carry, full_carry = bitwise_sub(processor.main_registers['a'], value_to_compare)
src_addr = (src_addr + increment) % 0x10000
processor.set_16bit_reg('hl', src_addr)
new_bc = _decrement_bc(processor)
processor.set_condition('s', result & 0b10000000 != 0)
processor.set_condition('z', result == 0)
processor.set_condition('h', half_carry)
processor.set_condition('p', new_bc != 0)
processor.set_condition('n', True)
def _block_compare(processor, memory, increment):
src_addr = processor.get_16bit_reg('hl')
value_to_compare = memory[src_addr]
result, half_carry, full_carry = bitwise_sub(processor.main_registers['a'],
value_to_compare)
src_addr = (src_addr + increment) % 0x10000
processor.set_16bit_reg('hl', src_addr)
new_bc = _decrement_bc(processor)
processor.set_condition('s', result & 0b10000000 != 0)
processor.set_condition('z', result == 0)
processor.set_condition('h', half_carry)
processor.set_condition('p', new_bc != 0)
processor.set_condition('n', True)