206 Chapter 37. SPARC Dependent FeaturesYou can use the -enforce-aligned-data option to make SPARC GAS also issue an error aboutmisaligned 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 PointThe Sparc uses ieee floating-point numbers.37.4. Sparc Machine DirectivesThe Sparc version of as supports the following additional machine directives:.alignThis must be followed by the desired alignment in bytes..commonThis must be followed by a symbol name, a positive number, and "bss". This behaves somewhatlike .comm, but the syntax is different..halfThis is functionally identical to .short..nwordOn the Sparc, the .nword directive produces native word sized value, ie. if assembling with -32it is equivalent to .word, if assembling with -64 it is equivalent to .xword..procThis directive is ignored. Any text following it on the same line is also ignored..registerThis directive declares use of a global application or system register. It must be followed by aregister name %g2, %g3, %g6 or %g7, comma and the symbol name for that register. If symbolname is #scratch, it is a scratch register, if it is #ignore, it just suppresses any errors aboutusing 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..reserveThis must be followed by a symbol name, a positive number, and "bss". This behaves somewhatlike .lcomm, but the syntax is different..segThis must be followed by "text", "data", or "data1". It behaves like .text, .data, or.data 1.
