.pg
.x of
.x otherwise
.x Obsolete Macros > of
.x Obsolete Macros > otherwise
.lt
------------------------------------------------------------------------
CASE	index <label-list> [BASE=base] [TYPE=type] DO
  label_1: OF
      ...
           END
  label_2: OF
      ...
           END
  .
   .
    .

  label_n: OF
      ...
           END
  OTHERWISE
    ...
END
------------------------------------------------------------------------
.el
.b 3
These macros implements the CASEB, CASEW or CASEL VAX instruction, generates
the case table from a list of branch distinations and calculates the index
limit. 
.b
If ^&base\& is not specified, #0 is assumed.
If ^&type\& is not specified, L is assumed. 
.b
The END macro for the OF statement will generate a branch to the end of the
case structure. If the branch displacement for CASE is BYTE, a BRB instruction
will be generated, if the branch displacement is WORD, a BRW instruction will
be generated, and if the branch displacement is LONG, a JMP instruction will be
genereated. 
.b
The default branch displacement for CASE is WORD (see BRANCH). 
.b
The OTHERWISE macro begins code statements for the default case (i.e. when the
case index is outside the _<^&label-list\&_> supplied). The OTHERWISE macro and
it's corresponding code statements are optional. 
.b
For every CASE macro specified, a corresponding END macro must also be
specified. The END macro corresponding to the CASE macro will generate the
appropriate labels. For every OF macro specified, a corresponding END macro
must also be specified.
.b
.tp 5
For example:
.b
.lt
	case r1 <one,two,three> base=#1 do
	one:	of
			statements-1
		end
	two:	of
			statements-2
		end
	three:	of
			statements-3
		end
	otherwise
		statements-0
	end
.el
.b
will generate the following code:
.b
.lt
		casel	r1,#1,#<<30001$-30000$>/2>-1
	30000$:
		.word	one-30000$
		.word	two-30000$
		.word	three-30000$
	30001$:
		brw	20000$
	one:
		statements-1
		brw	20001$
	two:
		statements-2
		brw	20001$
	three:
		statements-3
		brw	20001$
	20000$:
		statements-0
	20001$:
.el