Supported Extensions

The supported GNU extensions, regardless whether you enable GNU assembler compatible syntax are as follows:

Lines beginning with #, * or ; are always treated as comment, even if the comment symbol for that assembler is someting different.
Escape characters in strings extended to include \xNN for hex digits and \NNN for octal.
Binary constants can begin with 0b.
The supported GNU macro language, with macros defined by:
.macro name,arg1[=default1],arg2...s1

...

.endm

Arguments can have default values as shown, and when called can be specified by value or position. (refer to the GNU documentation for details.)
New or enhanced directives (refer to the GNU documentation for details.)

The following table lists the supported GNU assembler directives.

Table 1. Supported GNU Assembler Directives
Directive	Description	Comment
`.abort`	End assembly	Supported
`.align N,[pad]`	Align	Now accepts optional padding byte
`.app-file name`	Source name	Synonym for .file
`.balign[wl] N,[pad]`	Align	Align to N (with optional padding value)
`.common name,length`	Common data	Reserve space in BSS for global symbol
`.def`	Debugging	Accepted but ignored
`.desc`	Debugging	Accepted but ignored
`.dim`	Debugging	Accepted but ignored
`.eject`	Eject page	Accepted but ignored
`.endr`	End repeat	refer .irp, .irpc
`.endef`	Debugging	Accepted but ignored
`.fill N,[size],[val]`	Repeat data	Emit N copies of width `size', value `val'
`.hword val..`	Half-word	Synonym for .short
`.ident`	Tags	Accepted but ignored
`.ifnotdef name`	Conditional	Synonym for .ifndef
`.include name`	Include file	Now accepts single, double or no quotes
`.init val..`	Word	Synonym for .long
`.irp name,values`	Repeat	Repeat up to .endr substituting values for name
`.irpc name,chars`	Repeat	Repeat up to .endr substituting chars for name
`.lcomm name,length`	Local common	Reserve length bytes in bss
`.Iflags`	Ignored	Accepted but ignored
`.ln lineno`	Line number	Synonym for .line
`.list`	Listing on	Switch on listing
`.local name`	Local Macro var	Declare name as local to macro
`.macro name, args..`	Macros	Supports GNU syntax, default values, etc
`.nolist`	Listing off	Disable listing
`.org pos,fill`	Origin	Now allows fill value to be specified
`.p2align[wl] N[,pad]`	Align	Align to 2**N, using pad value `pad'
`.psize`	Page size	Accepted but ignored
`.rept N`	Repeat	Repeat block up to .endr N times
`.sbttl`	Subtitle	Accepted but ignored
`.scl`	Debugging	Accepted but ignored
`.size name,N`	Set size	Set size of name to N
`.skip N[,pad]`	Space	Skip N bytes, pad with `pad'
`.space N[,pad]`	Space	Skip N bytes, pad with `pad'
`.stabd`	Debugging	Accepted but ignored
`.stabn`	Debugging	Accepted but ignored
`.stabs`	Debugging	Accepted but ignored
`.str "string"`	Contstant string	Synonym for .asciz
`.string "string"`	Constant String	Synonym for .asciz
`.tag`	Debugging	Accepted but ignored
`.title`	Title	Accepted but ignored
`.type`	Debugging	Ignored in GNU mode
`.val`	Debugging	Accepted but ignored
`.word`	Word	Synonym for .long