HLASM: V1R6 Language Ref

Operand entries– For Branch on Index High (BXH) and the Branch on Index Low or Equal(BXLE) instructions, if the register specified for the second operand is aneven-numbered register, the next higher odd-numbered register is used tocontain the value to be used for comparison.– For Load Multiple (LM, LAM) and Store Multiple (STM, STAM) instructions,the registers that lie between the registers specified in the first two operands.– For extended-precision floating point instructions, the second register of theregister pair.– For Compare and Form Codeword (CFC) instruction, registers 1, 2 and 3 areused.– For Translate and Test (TRT) instruction, registers 1 and 2 are used.– For Update Tree (UPT) instruction, registers 0-5 are used.– For Edit and Mark (EDMK) instruction, register 1 is used.– For certain control instructions, one or more of registers 0-4 and register 14are used. See “Control Instructions” in the applicable Principles of Operationmanual.– For certain input/output instructions, either or both registers 1 and 2 areused. See “Input/Output Instructions” in the applicable Principles of Operationmanual.– On a processor with a vector facility:1. For instructions that manipulate long floating-point data in vectorregisters, the odd-numbered vector registers, whose number is one greaterthan the even-numbered vector registers specified in each operand.2. For instructions that manipulate 64-bit signed binary data in vectorregisters, the odd-numbered vector registers, whose number is one greaterthan the even-numbered vector registers specified in each operand.Register usage by systemThe programming interface of the system control programs uses registers 0, 1, 13,14, and 15.AddressesYou can code a symbol in the name field of a machine instruction statement torepresent the address of that instruction. You can then refer to the symbol in theoperands of other machine instruction statements. The object code requires thataddresses be assembled in a numeric relative-offset or base-displacement format.This format lets you specify addresses that are relocatable or absolute. Chapter 3,“Program structures and addressing,” on page 49 describes how you use symbolicaddresses to refer to data in your assembler language program.84 HLASM: V1R6 Language RefDefining Symbolic Addresses: Define relocatable addresses by either using asymbol as the label in the name field of an assembler language statement, orequating a symbol to a relocatable expression.Define absolute addresses (or values) by equating a symbol to an absoluteexpression.Referring to Addresses: You can refer to relocatable and absolute addresses in theoperands of machine instruction statements. (Such address references are alsocalled addresses in this manual.) The two ways of coding addresses are:v Implicitly—in a form that the assembler must first convert into an explicitrelative-offset or base-displacement form before it can be assembled into objectcode.