HLASM: V1R6 Language Ref

Terms, literals, and expressionsv Build expressions to be evaluated by the assemblerThe symbol length attribute reference must be specified according to the followingrules:v The format must be L' immediately followed by a valid symbol (L'SYMBOL), anexpression (L'SYMBOL+SYMBOL2-SYMBOL7), or the location counter reference (L'*). Ifthe operand is an expression, the length attribute of its leftmost term is used.v Symbols must be defined in the same source module in which the symbol lengthattribute reference is specified.v The symbol length attribute reference can be used in the operand of anyinstruction that requires an absolute term. However, it cannot be used in theform L'* in any instruction or expression that requires a previously definedsymbol.The value of the length attribute is normally the length in bytes of the storage arearequired by an instruction, constant, or field represented by a symbol. Theassembler stores the value of the length attribute in the symbol table along withthe address value assigned to the symbol.When the assembler encounters a symbol length attribute reference, it substitutesthe value of the attribute from the symbol table entry for the symbol specified.The assembler assigns the length attribute values to symbols in the name field ofinstructions as follows:v For machine instructions (see ▌1▐ in Table 6 on page 39), it assigns either 2, 4, or6, depending on the format of the instruction.v For the DC and DS instructions (see ▌2▐ in Table 6), it assigns either theimplicitly or explicitly specified length of the first or only operand. The lengthattribute is not affected by a duplication factor.v For the EQU instruction, it assigns the length attribute value of the first or onlyterm (see ▌3▐ in Table 6) of the first expression in the first operand, unless aspecific length attribute is supplied in a second operand.Note the length attribute values of the following terms in an EQU instruction:– Self-defining terms (see ▌4▐ in Table 6)– Location counter reference (see ▌5▐ in Table 6)– L'* (see ▌6▐ in Table 6)For assembler instructions such as DC, DS, and EQU, the length attribute of thelocation counter reference (L'* — see ▌6▐ in Table 6) is equal to 1. For machineinstructions, the length attribute of the location counter reference (L'* — see ▌7▐ inTable 6) is equal to the length attribute of the instruction in which the L'* appears.38 HLASM: V1R6 Language Ref