IP2022 User’s Manual—Instruction Set Architecture www.ubicom.com 75 flags  of  the  STATUS  register;  the  result  of  the  subtraction  is
discarded. There  are  instructions  available  that  increment  or  decrement  a
register  and  simultaneously  test  the  result.  If  the  8-bit  result  is
zero,   the   next   instruction   in   the   program   is   skipped.   These
instructions can be used to make program loops. There are also
compare-and-skip instructions which perform the same operation
as subtract, then perform a conditional skip without affecting either
operand or the condition flags in the STATUS register. All of the arithmetic and shift instructions take one clock cycle for
execution,  except  in  the  case  of  the  test-and-skip  instructions
when the tested condition is true and a skip occurs, in which case
the instruction takes two cycles. 3.2.5 Bit Operation Instructions There are four bit operation instructions: • setb—sets  a  single  bit  in  a  data  register  without  affecting other bits • clrb—clears a single bit in a data register without affecting other bits • sb—tests a single bit in a data register and skips the next in- struction if the bit is set • snb—tests a single bit in a data register and skips the next in- struction if the bit is clear