CALL

This instruction initiates a subroutine. The flags are not affected.

First, it pushes the return address (the address of the instruction following the CALL) onto the stack. Then, it jumps to the subroutine address, i.e., copies the jump address into IP.

Usage

CALL label

label must be a label that points to an instruction.

Example

            org 3000h
subroutine: push ax
            ; --- etc ---
            ret

            org 2000h
            call subroutine ; Valid
            call 3000h      ; Invalid, must be a label
            hlt
            end

Encoding

00110001, addr-low, addr-high