HLASM Language Reference

Model Statements
Concatenation of Fields Containing Double-Byte Data: If the DBCS assembler
option is specified, then the following additional rules apply:
Because ampersand is not recognized in double-byte data, variable symbols
must not be present in double-byte data.
The concatenation character is mandatory when double-byte data is to follow a
variable symbol.
The assembler checks for redundant SI and SO at concatenation points. If the
byte to the left of the join is SI and the byte to the right of the join is SO, then
the SI/SO pair is considered redundant and is removed.
Note: The rules for redundant SI and SO are different for variable substition
and listing display, which are described at “Listing of Generated Fields
Containing Double-Byte Data” on page 249.
The following example shows these rules:
&SYMBOL SETC
''
DBCS DC C'&SYMBOL.'
The SI/SO pairs between double-byte characters Db and Dc, and Dd and .&, are
removed. The variable symbol &SYMBOL is recognized between the double-byte
strings but not in the double-byte strings. The result after concatenation is:
DBCS DC C''
Rules for Model Statement Fields
The fields that can be specified in model statements are the same fields that can
be specified in an ordinary assembler language statement. They are the name,
operation, operand, and remarks fields. You can also specify a
continuation-indicator field, an identification-sequence field, and, in source macro
definitions, a field before the begin column if the correct ICTL instruction has been
specified. Character strings in the last three fields (in the standard format only,
columns 72 through 80) are generated exactly as they appear in the model
statement, and no values are substituted for variable symbols.
Model statements must have an entry in the operation field, and, in most cases, an
entry in the operand field in order to generate valid assembler language
instructions.
Name Field
The entries allowed in the name field of a model statement, before generation, are:
Space
An ordinary symbol
A sequence symbol
A variable symbol
Any combination of variable symbols, or system variable symbols such as
&SYSNDX, and other character strings concatenated together
The generated result must be spaces (if valid) or a character string that represents
a valid assembler or machine instruction name field. Double-byte data is not valid
in an assembler or machine instruction name field and must not be generated.
Variable symbols must not be used to generate comment statement indicators ( or
.).
Chapter 7. How to Specify Macro Definitions 251