Branch Group:

The branching instructions alter normal sequential program flow, either unconditionally or conditionally. The unconditional branching instructions are as follows:

 

JMP           Jump

CALL          Call

RET           Return

 

Conditional branching instructions examine the status of one of four condition flags to determine whether the specified branch is to be executed. The conditions that may be specified are as follows:

 

NZ            Not Zero (Z = 0)

Z             Zero (Z = 1)

NC            No Carry (C = 0)

C             Carry (C = 1)

PO            Parity Odd (P = 0)

PE            Parity Even (P        = 1)

P             Plus (S = 0)

M             Minus (S = 1)

 

Thus, the conditional branching instructions are specified as follows:

 

Jumps         Calls        Returns

C             CC            RC      (Carry)

INC           CNC           RNC     (No Carry)

JZ            CZ            RZ      (Zero)

JNZ           CNZ           RNZ     (Not Zero)

JP            CP            RP      (Plus)

JM            CM            RM      (Minus)

JPE           CPE           RPE     (Parity Even)

JP0           CPO           RPO     (Parity Odd)

 

Two other instructions can affect a branch by replacing the contents or the program counter:

 

PCHL          Move H & L to Program Counter

RST           Special Restart Instruction Used

              with Interrupts