HLASM: V1R6 Language Ref

SET symbols&X(2,33,55) becomes &X2$33$55&X(23,35,5) becomes &X23$35$5DataattributesThe data, such as instructions, constants, and areas, that you define in a sourcemodule, can be described by its:v Type, which distinguishes a property of a named object or macro argument, forexample, fixed-point constants from floating-point constants, or machineinstructions from macro instructionsv Length, which gives the number of bytes occupied by the object code of thenamed datav Scaling, which shows the number of positions occupied by the fractional portionof named fixed-point, floating-point, and decimal constants in their object codeformv Integer, which shows the number of positions occupied by the integer portion ofnamed fixed-point and decimal constants in their object code formv Count, which gives the number of characters that would be required torepresent the named data, such as a macro instruction operand, as a characterstringv Number, which gives the number of sublist entries in a macro instructionoperandv Defined, which determines whether a symbol has been defined prior to the pointwhere the attribute reference is codedv Operation Code, which shows if an operation code, such as a macro definitionor machine instruction, is defined prior to the point where the attribute referenceis codedThese characteristics are called the attributes of the symbols naming the data. Theassembler assigns attribute values to the ordinary symbols and variable symbolsthat represent the data.Specifying attributes in conditional assembly instructions allows you to controlconditional assembly logic, which, in turn, can control the sequence and contentsof the statements generated from model statements. The specific purpose for whichyou use an attribute depends on the kind of attribute being considered. Theattributes and their main uses are shown below:Table 51. Data attributesAttribute Purpose Main UsesType Gives a letter that identifies type ofdata representedLength Gives number of bytes that dataoccupies in storagev In tests to distinguishbetween different datatypesv For value substitutionv In macros to discovermissing operandsv For substitution into lengthfieldsv For computation of storagerequirementsChapter 9. How to write conditional assembly instructions 321