HLASM: V1R6 Language Ref

Input/output operationsThe input or output instructions let you identify the channel or the device onwhich the input or output operation is to be done. For information about how andwhen you can use these instructions, see the applicable system manual.For more information, see “Input/Output Operations” in the applicable Principlesof Operation manual and the applicable system manuals.Branching with extended mnemonic codesBranch instructions let you specify an extended mnemonic code for the condition onwhich a branch is to occur. Thus, you avoid having to specify the mask value, thatrepresents the condition code, required by the BC, BCR, and BRC machineinstructions. The assembler translates the extended mnemonic code into the maskvalue, and then assembles it into the object code of the BC, BCR, or BRC machineinstruction.The extended branch mnemonics for the BC instruction require a base register; theextended mnemonics for the BCR and BRC instructions do not. The extendedmnemonics for the BRC instruction begin with the letter “J”, and are sometimescalled “Jump” instructions, as indicated in Figure 14.|Some typical extended mnemonic codes are given in Figure 14 on page 78. Theycan be used as operation codes for branching instructions, replacing the BC, BCR,and BRC machine instruction codes (see ▌1▐ in Figure 14). Note that the firstoperand (see ▌2▐ in Figure 14) of the BC, BCR, and BRC instructions must not bepresent in the operand field (see ▌3▐ in Figure 14) of the extended mnemonicbranching instructions.Chapter 4. Machine instruction statements 77