System Architecture—IP2022 User’s Manual 20 www.ubicom.com • INTVECH/INTVECL register—specifies the interrupt vector. It
has a default value of 0x0000 following reset. • IPH/IPL register—indirect pointer for indirect addressing. For
more   information   about   indirect   addressing,   see   Section
3.1.3. • DPH/DPL register and  SPH/SPL register—data pointer and
stack pointer for indirect-with-offset addressing. For more in-
formation  about  indirect-with-offset  addressing,  see  Section
3.1.4. The SPH and SPL registers are automatically postdec-
remented when storing to memory with a  push instruction,
and they are automatically preincremented when reading from
memory with a pop instruction. • ADDRSEL  register—holds  an  index  to  one  of  eight  24-bit
pointers used to address program memory. • ADDRX/ADDRH/ADDRL register—the current pointer select-
ed by the ADDRSEL register is accessable in the ADDRX (bits
23:16), ADDRH (bits 15:8), and ADDRL (bits 7:0) registers. • DATAH/DATAL register—program memory is always read or
written  as  16-bit  words.  On  reads,  the  data  from  program
memory is loaded into the DATAH/DATAL register. On writes,
the contents of the DATAH/DATAL register pair are loaded into
the program memory.