expression:
         opcode,op1,rel,op2
         opcode,op1,rel,op2,OR,opcode,op1,rel,op2
         opcode,op1,rel,op2,AND,opcode,op1,rel,op2
           opcode::=C,CH,CR,CLC,CLI,CLCL, LTR, CP,CE,CD,...
           rel::=EQ,NE,LT,LE,GT,GE,  (fortran style)
                 E,L,H,NE,NL,NH      (assembler style)
                 P (plus), M (minus) ,Z (zero) ,O (overflow)
           opcode::=CLM,TM
           rel::=O (ones),M (mixed) ,Z (zeros)

* IF
         IF     expression [THEN]
           ...
         ELSEIF expression [THEN]
           ...
         ELSE
           ...
         ENDIF

         IF     C,R4,EQ,=F'10' THEN     if     r4=10 then
           MVI  PG,C'A'                   pg='A'
         ELSEIF C,R4,EQ,=F'11' THEN     elseif r4=11 then
           MVI  PG,C'B'                   pg='B'
         ELSEIF C,R4,EQ,=F'12' THEN     elseif r4=12 then
           MVI  PG,C'C'                   pg='C'
         ELSE                           else
           MV   PG,C'?'                   pg='?'
         ENDIF                          end if

* SELECT
         SELECT expressionpart1
           WHEN expressionpart2a
             ...
           WHEN expressionpart2b
             ...
          OTHRWISE
             ...
         ENDSEL
		
* example SELECT type 1
         SELECT CLI,HEXAFLAG,EQ         select hexaflag=
           WHEN X'20'                     when x'20'
             MVI  PG,C'<'                   pg='<'
           WHEN X'21'                     when x'21'
             MVI  PG,C'!'                   pg='!'
           WHEN X'22'                     when x'21'
             MVI  PG,C'>'                   pg='>'
           OTHRWISE                       otherwise
             MVI  PG,C'?'                   pg='?'
         ENDSEL                         end select

* example SELECT type 2
         SELECT                         select
           WHEN C,DELTA,LT,0              when delta<0
             MVC  PG,=C'0 SOL'              pg='0 SOL'
           WHEN C,DELTA,EQ,0              when delta=0
             MVC  PG,=C'1 SOL''              pg='0 SOL'
           WHEN C,DELTA,GT,0              when delta>0
             MVC  PG,=C'2 SOL''              pg='0 SOL'
         ENDSEL                         end select

* CASE
         CASENTRY R4                    select case r4
           CASE 1                         case 1
             LA     R5,1                    r5=1
           CASE 3                         case 3
             LA     R5,2                    r5=2
           CASE 5                         case 5
             LA     R5,3                    r5=1
           CASE 7                         case 7
             LA     R5,4                    r5=4
         ENDCASE                        end select