IP2022 User’s Manual—Instruction Set Architecture www.ubicom.com 77 3.2.7 Program Control Instructions A  program  control  instruction  alters  the  flow  of  the  program  by
changing  the  contents  of  the  program  counter.  Included  in  this
category are the jump, call, return-from-subroutine, and interrupt
instructions. The jmp instruction has a single operand that specifies the entry
point at which to continue execution. The entry point is typically
specified in assembly language with a label, as in the following
code example. If  the  carry  bit  is  set  to  1,  the  jmp  instruction  is  executed  and
program   execution   continues   where   the   do_carry   label
appears in the program. The  call  instruction  works  in  a  similar  manner,  except  that  it
saves the contents of the program counter before jumping to the
new  address.  It  calls  a  subroutine  that  is  terminated  by  a  ret
instruction, as shown in the following code example. snb status,0 ;test the carry bit jmp do_carry ;jump to do_carry routine if C = 1 ...
do_carry: ;jump destination label ... ;execution continues here