instructions.py 文件源码

def addc(self, a, b, c):

        if 0 == self.pc_state.P.get_D():
            r  = ctypes.c_short(a + b + c).value
            rc = ctypes.c_byte(a + b + c).value
            self.pc_state.P.set_N((0,1)[0x80 == (rc & 0x80)])
            self.pc_state.P.set_Z((0,1)[rc == 0x0])
            self.pc_state.P.set_V((0,1)[rc != r])   # Overflow

            r = ((a & 0xFF) + (b & 0xFF) + c) & 0xFFFF
            self.pc_state.P.set_C((0,1)[0x100 == (r & 0x100)])
            result = (a + b + c)
        elif 1 == self.pc_state.P.get_D():
            # Decimal Addition
            # FIXME need to fix flags
            #
            r = ctypes.c_short(((a >> 4) & 0xF)* 10+ ((a & 0xF) %10) + ((b>>4) & 0xF)* 10 + ((b & 0xF) %10) + c).value
            rc = ctypes.c_byte(a + b + c).value # ???? TODO
            self.pc_state.P.set_N((0,1)[r < 0])
            self.pc_state.P.set_Z((0,1)[rc == 0x0])
            # self.pc_state.P.V = (rc != r) ? 1:0;   # Overflow

            self.pc_state.P.set_C((0,1)[(r > 99) or (r < 0)])
            result = (((((r/10) % 10) << 4) & 0xf0) + (r%10))

        return result & 0xFF