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Branching Group Instructions (Part-III) - Return and Conditional return

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RET:
  • This instruction transfers the program control from subroutine or subprogram to the main program.
  • It pops the address of the instruction next to CALL instruction in the main program from the stack and loads program counter with this address.
  • Then stack pointer is incremented by two.
  • No flags are affected.
  • It is a one byte instruction.
  • Register indirect addressing mode is used because the return address is available in the memory location pointed by stack pointer.
Example:
If SP = 2000H
RET ; This instruction will load program counter with 3000H and will transfer program control to 3000H.

Before execution:
After execution:

Rcond:
  • When the condition is true, this instruction transfers the program control from subprogram or subroutine to the main program.
  • It pops the address of the instruction next to CALL instruction from the stack and loads program counter with this address.
  • Then stack pointer is incremented by two.
  • When the condition is false, nothing happens.
  • No flags are affected. They are only checked.
  • It is a one byte instruction.
  • Register indirect addressing mode is used because the return address is available in the memory location pointed by stack pointer.
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