Control Flag:- Out of nine active flags, six are conditional flags and the remaining three are called as the control flag. The three control flags are:

1. The Trap flag(TF)
2. The interrupt flag(IF)
3. The direction flag(DF)

The Trap Flag: · Setting TF puts the processor into single step mode for debugging, In single stepping microprocessor executes a instruction and enters into single step ISR. · If TF=1, the CPU automatically generates an internal interrupt after each instruction, allowing a program to be inspected as it executes instruction by instruction.

The Interrupt Flag:- · If IF=1, the CPU will recognize external interrupt request (Interrupt Disabled). If IF=0, then interrupt disabled. · Clearing IF disables these interrupts. · IF has no effect on either non-maskable external or internally generated interrupt.

The Direction Flag:- · This bit is specially for string instructions. · If DF=1, the string instruction will automatically decrement the pointer. If DF=0,the string instruction will automatically increment the pointer.

Control flags

They are set using certain instructions. They are used to control certain operations of the processor.

a) TF (Trap Flag):

This flag is used if we need single-step debugging in our code. If the TF is set, then the execution will be done step by step by generating …