46

Chapter 8. Assembler Directives

8.17.

.cfi_window_save

SPARC register window has been saved.

8.18.

.cfi_escapeexpression

[, . . . ]

Allows the user to add arbitrary bytes to the unwind info. One might use this to add OS specific CFI

opcodes, or generic CFI opcodes that GAS does not yet support.

8.19.

.data subsection

.data

tells

as

to assemble the following statements onto the end of the data subsection numbered

subsection

(which is an absolute expression). If

subsection

is omitted, it defaults to zero.

8.20.

.def name

Begin defining debugging information for a symbol

name

; the definition extends until the

.endef

directive is encountered.

This directive is only observed when

as

is configured for COFF format output; when producing

b.out

,

.def

is recognized, but ignored.

8.21.

.desc symbol, abs expression

This directive sets the descriptor of the symbol (Section 6.5 Symbol Attributes) to the low 16 bits of

an absolute expression.

The

.desc

directive is not available when

as

is configured for COFF output; it is only for

a.out

or

b.out

object format. For the sake of compatibility,

as

accepts it, but produces no output, when

configured for COFF.

8.22.

.dim

This directive is generated by compilers to include auxiliary debugging information in the symbol

table. It is only permitted inside

.def

/

.endef

pairs.

.dim

is only meaningful when generating COFF format output; when

as

is generating

b.out

, it

accepts this directive but ignores it.

8.23.

.double flonums

.double

expects zero or more flonums, separated by commas. It assembles floating point numbers.

The exact kind of floating point numbers emitted depends on how

as

is configured. Chapter 9 Machine

Dependent Features.

8.24.

.eject

Force a page break at this point, when generating assembly listings.