HLASM: V1R6 Language Ref

OPSYN instructionAn OPSYN instruction that redefines the operation code of an assembler ormachine instruction generated from a macro instruction is, however, effectiveimmediately, even if the definition of the macro was made prior to the OPSYNinstruction. Consider the following example:MACRO Macro headerMAC ... Macro prototypeAIF ...MVC ....MEND Macro trailer.AIF OPSYN AGO Assign AGO properties to AIFMVC OPSYN MVI Assign MVI properties to MVC.MAC ... Macro call(AIF interpreted as AIF instruction;generated AIFs not printed)+ MVC ... Interpreted as MVI instruction.. Open code started at this pointAIF ... Interpreted as AGO instructionMVC ... Interpreted as MVI instructionIn this example, AIF and MVC instructions are used in a macro definition. AIF is aconditional assembly instruction, and MVC is a machine instruction. OPSYNinstructions are used to assign the properties of AGO to AIF and to assign theproperties of MVI to MVC. In subsequent calls of the macro MAC, AIF is stilldefined, and used, as an AIF operation, but the generated MVC is treated as anMVI operation. In open code following the macro call, the operations of bothinstructions are derived from their new definitions assigned by the OPSYNinstructions. If the macro is redefined (by another macro definition), the newdefinitions of AIF and MVC (that is, AGO and MVI) are used for furthergenerations.ORGinstructionThe ORG instruction alters the setting of the location counter and thus controls thestructure of the current control section. This redefines portions of a control section.If a control section has not been previously established, ORG will initiate anunnamed (private) control section.►►symbolORGexpression, boundary, offset,offset►◄symbolis one of the following:v An ordinary symbolv A variable symbol that has been assigned a character string with a value thatis valid for an ordinary symbolv A sequence symbolChapter 5. Assembler instruction statements 199