%EXTERNALINTEGERFN POWII %ALIAS "F_POWII"(%INTEGER IARG,NARG)
!
!     CALCULATES IARG**NARG
!
%INTEGER X,Y
%INTEGER N

X= IARG
Y= 1
N= NARG
%IF N=0 %then %result= 1
!%START
!  %IF X#0 %THEN %RESULT= 1 %ELSESTART
! Error message suppressed to give conformity with other systems.
!    %IF TEST=1 %THEN TERROR( IPOWERZERO ) %ELSE ERROR( IPOWERZERO )     
!    %RESULT= 1
!  %FINISH
!%FINISH

%IF X=1 %THEN %RESULT= 1
%IF X=-1 %START
  %IF N<0 %THEN N= -N
  %IF N&1=1 %THEN %RESULT= -1 %ELSE %RESULT= 1
%FINISH

!Error message suppressed to conform to '77' standard.
!%IF N<0 %START
!  %IF TEST=1 %THEN TERROR( IPOWEXPNEG ) %ELSE ERROR( IPOWEXPNEG )
!  %RESULT= 0
!%FINISH

%IF X=0 %or n<0 %THEN %RESULT= 0

%CYCLE
  %IF N&1#0 %THEN Y= Y*X
  N = N>>1
  %IF N#0 %THEN X= X*X %ELSE %EXIT
%REPEAT

%IF Y=0 %START
   %IF TEST=1 %THEN TERROR( IPOWLARGE ) %ELSE ERROR( IPOWLARGE )
  %RESULT= 0
%FINISHELSE %RESULT= Y
%END {OF POWII}