Instruction Set Architecture—IP2022 User’s Manual 120 www.ubicom.com CALL addr13 Call Subroutine Operation: top-of-stack = PC15:0 + 1
PC12:0 = addr13
PC15:13 = PA2:PA0 Bits affected: None Opcode: 110k kkkk kkkk kkkk Description: This instruction calls a subroutine. The full 16-bit
address of the next program instruction is saved
on the stack and the program counter is loaded
with a new address, which causes a jump to that
program address. Bits 12:0 come from the 13-bit constant value in
the  instruction,  and  bits  15:13  come  from  the
PA2:PA0 bits in the STATUS register. The    subroutine    is    terminated    by    a    ret
instruction, which restores the saved address to
the  program  counter.  Execution  proceeds  from
the instruction following the call instruction. Cycles: 3