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Chapter 37. SPARC Dependent Features

You can use the

 enforce aligned data

option to make SPARC GAS also issue an error about

misaligned data, just as the SunOS and Solaris assemblers do.

The

 enforce aligned data

option is not the default because gcc issues misaligned data pseudo 

ops when it initializes certain packed data structures (structures defined using the

packed

attribute).

You may have to assemble with GAS in order to initialize packed data structures in your own code.

37.3. Floating Point

The Sparc uses ieee floating point numbers.

37.4. Sparc Machine Directives

The Sparc version of

as

supports the following additional machine directives:

.align

This must be followed by the desired alignment in bytes.

.common

This must be followed by a symbol name, a positive number, and

"bss"

. This behaves somewhat

like

.comm

, but the syntax is different.

.half

This is functionally identical to

.short

.

.nword

On the Sparc, the

.nword

directive produces native word sized value, ie. if assembling with  32

it is equivalent to

.word

, if assembling with  64 it is equivalent to

.xword

.

.proc

This directive is ignored. Any text following it on the same line is also ignored.

.register

This directive declares use of a global application or system register. It must be followed by a

register name %g2, %g3, %g6 or %g7, comma and the symbol name for that register. If symbol

name is

#scratch

, it is a scratch register, if it is

#ignore

, it just suppresses any errors about

using undeclared global register, but does not emit any information about it into the object file.

This can be useful e.g. if you save the register before use and restore it after.

.reserve

This must be followed by a symbol name, a positive number, and

"bss"

. This behaves somewhat

like

.lcomm

, but the syntax is different.

.seg

This must be followed by

"text"

,

"data"

, or

"data1"

. It behaves like

.text

,

.data

, or

.data 1

.