Ep 083: Introduction to the Flags Register

Like the warning lights on a car's dashboard, the processor has a set of Boolean "flags" used to identify the configuration, status, and computational results of the processor at a glance. This video describes the flags used to determine the characteristics of the last operation including the sign of the result, if the result equaled zero, any carries or overflows that occurred, and the result's parity. Take aways: At the completion of this lesson, each student should be able to: • define what a flag register or program status word is and • explain the purpose of the zero, the sign, the overflow, the carry, the half carry, and the parity flags. Episodes referenced: Ep 007: Packed Binary Coded Decimal (BCD) (   • Ep 007: Packed Binary Coded Decimal  ) Ep 012: Addition and Subtraction in Binary (   • Ep 012: Addition and Subtraction in Binary  ) Ep 013: Basics of Complement Notation (   • Ep 013: Basics of Complement Notation  ) Ep 015: Overflow in Binary Integer Addition (   • Ep 015: Overflow in Binary Integer Addition  ) Ep 046: Introduction to Bitwise Operations and the Bitwise Inverse (   • Ep 046: Introduction to Bitwise Operations...  ) Ep 047: Clearing Bits using the Bitwise-AND (   • Ep 047: Clearing Bits using the Bitwise-AND  ) Ep 048: Setting Bits using the Bitwise-OR (   • Ep 048: Setting Bits using the Bitwise-OR  ) Ep 049: Flipping Bits using the Bitwise-XOR (   • Ep 049: Flipping Bits using the Bitwise-XOR  ) Ep 050: Using Parity for Simple Error Detection (   • Ep 050: Using Parity for Simple Error Dete...  ) #cpuflags #flags #registers