OCR: Wed Aughntt. allowed In supervisorgmedeg Sdbitostttotdanthesomstrarotions aregaltowred When in UBepe mode access to the system byte prohibited so that user mode programs can t switch into superv isor mode Bits 10 to 8 are called the interrupt mask These will not be dealt with here User byte. The user byte carries bits known as the condition codes, which are flags used to record the outcome of the last arithmetic operation performed The c flag the carry flag If two 8 bits numbers are added, the C bit is the ninth bit of the result. The flag is the overflow flag. If a result overflows. then the v flag will be set. Overflow means that the result could not be properly represented For example, suppose we ape two bytes together The MSB of each byte the sign bit If both numbers were positive, the ...
