They straightforwardly affect the content of the flags.
CLC
CLD
CLI
CMC
STC
STD
STI
CLC INSTRUCTION
Reason: To uncontaminated the cartage flag.
Syntax:
CLC
This instruction turning the bit corresponding to the cartage flag, or in extra words it puts it on zero.
CLD INSTRUCTION
Reason: To uncontaminated the address flag.
Syntax:
CLD
This instruction exits the corresponding bit to the address flag.
CLI INSTRUCTION
Reason: To uncontaminated the interruption flag.
Syntax:
CLI
This instruction exits the interruptions flag, disabling this way those maskarable interruptions.
A maskarable interruptions is that one whose functions are disabled when IF=0.
CMC INSTRUCTION
Reason: To balance the cartage flag.
Syntax:
CMC
This instruction goes together the state of the CF flag, if CF = 0 the instructions equals it to 1, and if the instruction is 1 it equals it to 0.
We might say that it only "inverts" the value of the flag.
STC INSTRUCTION
Reason: To make active the cartage flag.
Syntax:
STC
This instruction locates the CF flag in 1.
STD INSTRUCTION
Reason: To make active the address flag.
Syntax:
STD
The STD instruction puts the DF flag in 1.
STI INSTRUCTION
Reason: To set in motion the interruption flag.
Syntax:
STI
The instruction sets off the IF flag, and this enables the maskarable external interruptions ( the ones which only function when IF = 1).