Assembler instructions and statements

Table 1 summarizes the basic formats of assembler instructions, and Table 2 summarizes assembler statements.

Table 1. Assembler instructions
Operation Entry	Name Entry	Operand Entry
ACONTROL⁵	A sequence symbol or space	One or more operands, separated by commas
ACTR	A sequence symbol or space	An arithmetic SETA expression
ADATA⁵	A sequence symbol or space	One-to-four decimal, self-defining terms, and one character string, separated by commas.
AEJECT²	A sequence symbol or space	Taken as a remark
AGO	A sequence symbol or space	A sequence symbol
AIF	A sequence symbol or space	A logical expression enclosed in parentheses, immediately followed by a sequence symbol
AINSERT⁵	A sequence symbol or space	A character string, followed by FRONT or BACK
AMODE	Any symbol or space	24, 31, 64, ANY, or ANY31
ALIAS⁵	A symbol	A character string or a hexadecimal string
ANOP	A sequence symbol or space	Taken as a remark
AREAD²	Any SETC symbol	NOPRINT, NOSTMT, CLOCKB, CLOCKD, or spaces
ASPACE	A sequence symbol or space	An absolute expression
CATTR (z/OS and CMS)	A valid program object external class name	One or more attributes
CCW⁴	Any symbol or space	Four operands, separated by commas
CCW0⁴	Any symbol or space	Four operands, separated by commas
CCW1⁴	Any symbol or space	Four operands, separated by commas
CEJECT⁵	A sequence symbol or space	An absolute expression or space
CNOP⁴	Any symbol or space	Two absolute expressions, separated by a comma
COM	Any symbol or space	Taken as a remark
COPY⁵	A sequence symbol or space	An ordinary symbol, or, for open code statements, a variable symbol
CSECT	Any symbol or space	Taken as a remark
CXD⁴	Any symbol or space	Taken as a remark
DC⁴	Any symbol or space	One or more operands, separated by commas
DROP	A sequence symbol or space	One or more absolute expressions and symbols, separated by commas, or space
DS⁴	Any symbol or space	One or more operands, separated by commas
DSECT	A symbol or space	Taken as a remark
DXD⁵	A symbol	One or more operands, separated by commas
EJECT⁵	A sequence symbol or space	Taken as a remark
END	A sequence symbol or space	A relocatable expression or space
ENTRY⁵	A sequence symbol or space	One or more relocatable symbols, separated by commas
EQU⁴	A variable symbol or an ordinary symbol	One to five operands, separated by commas
EXITCTL⁵	A sequence symbol or space	A character-string operand followed by one to four decimal self-defining terms, separated by commas
EXTRN⁵	A sequence symbol or space	One or more relocatable symbols, separated by commas
GBLA	A sequence symbol or space	One or more variable symbols that are to be used as SET symbols, separated by commas¹
GBLB	A sequence symbol or space	One or more variable symbols that are to be used as SET symbols, separated by commas¹
GBLC	A sequence symbol or space	One or more variable symbols that are to be used as SET symbols, separated by commas¹
ICTL	Space	One to three decimal self-defining terms, separated by commas
ISEQ⁵	A sequence symbol or space	Two decimal self-defining terms, separated by a comma, or space
LCLA	A sequence symbol or space	One or more variable symbols that are to be used as SET symbols, separated by commas¹
LCLB	A sequence symbol or space	One or more variable symbols that are to be used as SET symbols, separated by commas¹
LCLC	A sequence symbol or space	One or more variable symbols separated by commas¹
LOCTR	A variable or ordinary symbol	Space
LTORG	Any symbol or space	Taken as a remark
MACRO^2,5	Space	Taken as a remark
MEND^2,5	A sequence symbol or space	Taken as a remark
MEXIT^2,5	A sequence symbol or space	Taken as a remark
MHELP	A sequence symbol or space	Absolute expression, binary, or decimal options
MNOTE	A sequence symbol or space	A severity code, followed by a comma, followed by a character string enclosed in apostrophes. Double-byte characters are permitted if the DBCS assembler option is specified.
OPSYN	An ordinary symbol An operation code mnemonic	A machine instruction mnemonic or an operation code defined by a previous macro definition or OPSYN instruction Space
ORG	A sequence symbol or space	A relocatable expression or space
POP⁵	A sequence symbol or space	One or more operands, separated by commas
PRINT⁵	A sequence symbol or space	One or more operands, separated by commas
PUNCH⁵	A sequence symbol or space	A 1-to-80-character string enclosed in apostrophes. Double-byte characters are permitted if the DBCS assembler option is specified.
PUSH⁵	A sequence symbol or space	One or more operands, separated by commas
REPRO⁵	A sequence symbol or space	Taken as a remark
RMODE	Any symbol or space	24, 31, 64, or ANY
RSECT	Any symbol or space	Taken as a remark
SETA	A SETA symbol	An arithmetic expression
SETAF	A SETA symbol	An external function module, and the arithmetic expressions it requires, separated by commas
SETB	A SETB symbol	A 0 or a 1, or a logical expression enclosed in parentheses
SETC	A SETC symbol	A type attribute, a character expression, a substring notation, or a concatenation of character expressions and substring notations. Double-byte characters are permitted if the DBCS assembler option is specified.
SETCF	A SETC symbol	An external function module, and the character expressions it requires, separated by commas
SPACE⁵	A sequence symbol or space	An absolute expression
START	Any symbol or space	An absolute expression or space
TITLE^3,5	A 1-to-8-character string, a variable symbol, a combination of character string or variable symbol, a sequence symbol, or space	A 1-to-100-character string enclosed in apostrophes. Double-byte characters are permitted if the DBCS assembler option is specified.
USING	A symbol or space	Either a single absolute or relocatable expression or a pair of absolute or relocatable expressions enclosed in parentheses and followed by 1 to 16 absolute expressions, separated by commas, or followed by a relocatable expression
WXTRN⁵	A sequence symbol or space	One or more relocatable symbols, separated by commas
XATTR⁵ (z/OS and CMS)	An external symbol	One or more operands, separated by commas

Notes: SET symbols can be defined as subscripted SET symbols. Can only be used as part of a macro definition. See TITLE instruction for a description of the name entry. These instructions start a private section. These instructions can be specified before the first executable control section.

Table 2. Assembler statements
Instruction Entry	Name Entry	Operand Entry
ModelStatements^{1 and 2}	An ordinary symbol, variable symbol, sequence symbol, or a combination of variable symbols and other characters that is equivalent to a symbol, or space	Any combination of characters (including variable symbols)
Prototype Statement³	A symbolic parameter or space	Zero or more operands that are symbolic parameters (separated by commas), and zero or more operands (separated by commas) of the form symbolic parameter, equal sign, optional standard value
Macro Instruction Statement³	An ordinary symbol, a variable symbol, or a combination of variable symbols and other characters that is equivalent to a symbol, any character string, a sequence symbol⁴ or space	Zero or more positional operands (separated by commas), and zero or more keyword operands (separated by commas) of the form keyword, equal sign, value⁵
Assembler Language Statement¹²	An ordinary symbol, a variable symbol, a sequence symbol, or a combination of variable symbols and other characters that is equivalent to a symbol, or space	Any combination of characters (including variable symbols)
Notes: Variable symbols can be used to generate assembler language mnemonic operation codes (listed in Assembler instruction statements), except COPY, ICTL, ISEQ, and REPRO. Variable symbols cannot be used in the name and operand entries of COPY, ICTL, and ISEQ instructions, except for the COPY instruction in open code, where a variable symbol is allowed for the operand entry. No substitution is done for variables in the line following a REPRO statement. Can only be used as part of a macro definition. When the name field of a macro instruction contains a sequence symbol, the sequence symbol is not passed as a name field parameter. It only has meaning as a possible branch target for conditional assembly. Variable symbols appearing in a macro instruction are replaced by their values before the macro instruction is processed.