HLASM Language Reference

OPSYN Instruction
Delete Operation Code
►►──operation_code_1──OPSYN────────────────────────────────────────►◄
symbol
is one of the following:
An ordinary symbol that is not the same as an existing operation code
A variable symbol that has been assigned a character string with a value
that is valid for an ordinary symbol and is not the same as an existing
operation code
operation_code_1
is one of the following:
An operation code described in this chapter, or in Chapter 4, “Machine
Instruction Statements” on page 78, or Chapter 9, “How to Write
Conditional Assembly Instructions” on page 318
The operation code defined by a previous OPSYN instruction
The name of a previously defined macro.
operation_code_2
is one of the following:
An operation code described in this chapter, or in Chapter 4, “Machine
Instruction Statements” on page 78, or Chapter 9, “How to Write
Conditional Assembly Instructions” on page 318
The operation code defined by a previous OPSYN instruction
In the first format, the OPSYN instruction assigns the properties of the operation
code denoted by operation_code_2 to the ordinary symbol denoted by symbol or
the operation code denoted by operation_code_1.
In the second format, the OPSYN instruction causes the operation code specified in
operation_code_1 to lose its properties as an operation code.
The OPSYN instruction can be coded anywhere in the program to redefine an
operation code.
The symbol in the name field can represent a valid operation code. It loses its
current properties as if it had been defined in an OPSYN instruction with a
space-filled operand field. In the following example, L and LR both possess the
properties of the LR machine instruction operation code:
L OPSYN LR
When the same symbol appears in the name field of two OPSYN instructions, the
latest definition takes precedence. In the example below, STORE now represents the
STH machine operation:
STORE OPSYN ST
STORE OPSYN STH
Note: OPSYN is not processed during lookahead mode (see “Lookahead” on
page 340). Therefore it cannot be used during lookahead to replace an opcode that
must be processed during lookahead, such as COPY. For example, assuming
Chapter 5. Assembler Instruction Statements 199