Comparison of language features

Element DOS/VSE Assembler Assembler H Version 2 High Level Assembler
Macro comment statements allowed in open code No No Yes
EQU instruction extension

Symbols appearing in the first operand of the EQU instruction need not have been previously defined.

 

 

Operands for assembler and program types.

 
 
No
 
 
 
 
No
 
 
Yes
 
 
 
 
No
 
 
Yes, program
type and
assembler type
operands
 
Yes
CNOP instruction extension

There is no restriction that symbols in the operand field of a CNOP instruction must have been previously defined.

 

Support for quadword alignment.

 
 
No
 
 
 
No
 
 
Yes
 
 
 
No
 
 
Yes, byte and
boundary
operands
 
Yes
COPY instruction extension

Any number of 'nestings', COPY statements within code that have been brought into your program by another COPY statement, is permitted.

No, nesting depth limited to 3 Yes Yes
COPY instruction processed immediately

COPY members are read immediately after a COPY statement is encountered in the source, regardless of whether or not conditional processing requires it, as in the following example:

       AGO    .LABEL
       COPY   AFILE
.LABEL ANOP
No, AFILE is never opened, read from, or processed in any way. Yes, AFILE is scanned during lookahead processing Yes, AFILE is scanned during lookahead processing
COPY instruction operand can, in open code, be specified as a variable symbol. No No Yes
ISEQ instruction extension

Sequence checking of any column on input records is allowed.

No Yes Yes
Macro names

Inline macro names may contain the underscore character (_).

No Yes Yes
Continuation lines Up to 2 Up to 9 Up to 9
Continuation lines and double-byte data No Yes Yes
Symbol name length up to 63 characters No, limited to 8 Yes Yes
Levels within expressions

Any number of terms or levels of parenthesis in an expression is allowed.

No Yes Yes
Underscores in symbols

You can specify the underscore character (_) in ordinary symbols and variable symbols.

No Yes Yes
Underscore character accepted in any position in symbol name No No Yes
Underscore character accepted in external symbols No No Yes
Underscore character accepted in name field of OPSYN instruction No No Yes
Maximum number of external symbols 511 65 535 65 535
DBCS language support

Pure double-byte data, and double-byte data mixed with single-byte data is permitted.

No Yes Yes
Location counter value printed for EQU, USING, ORG (in ADDR2 field) 3 bytes 4 bytes (up to 3 leading zeros suppressed). 4 bytes (up to 3 leading zeros suppressed).
Self-defining term
 
   Maximum value
 
   Number of digits
   Binary:
   Decimal:
   Hexadecimal:
   Characters:
 
 
224-1
 
 
24
8
6
3
 
 
231-1
 
 
31
10
8
4
 
 
231-1
 
 
31
10
8
4
Relocatable and absolute expressions
  • Value carried:
     
  • Number of operators:
  • Levels of parenthesis:
 

Truncated to 24 bits
15
5

 

Truncated to 31 bits
Not limited
Not limited

 

Truncated to 31 bits
 
Not limited
Not limited

All control sections initiated by a CSECT start at location 0 in listing and object module. Yes No Controlled by THREAD option
Copy files read once Copy files read when statement is found Copy files read when macro is edited (only once) Copy files read when macro is edited (only once)
Operand greater than 1024 characters when SUBLIST Error diagnostic with message and return code of 8 Error diagnostic with message and return code of 12 No
Remarks generated because of generated blanks in operand field No Yes Yes
Blank lines treated as equivalent to SPACE 1. No No Yes
Literals usable as relocatable terms in expressions No No Yes
Literals usable in RX format instructions in which index register is used No No Yes
Mixed case input No No Yes
2-byte relocatable address constants No No Yes
Multi-level PUSH supported

For example, PUSH USING,USING

No Yes. Not documented. No

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