.align abs-expr , abs-expr

Pad the location counter (in the current subsection) to a particular storage boundary. The first expression (which must be absolute) is the alignment required, as described below. The second expression (also absolute) gives the value to be stored in the padding bytes. It (and the comma) may be omitted. If it is omitted, the padding bytes are zero.

The way the required alignment is specified varies from system to system. For the a29k, HPPA, m86k, m88k, w65, sparc, and i386 using ELF format, the first expression is the alignment request in bytes. For example `.align 8' advances the location counter until it is a multiple of 8. If the location counter is already a multiple of 8, no change is needed.

For other systems, including the i386 using a.out format, it is the number of low-order zero bits the location counter must have after advancement. For example `.align 3' advances the location counter until it a multiple of 8. If the location counter is already a multiple of 8, no change is needed.

This inconsistency is due to the different behaviors of the various native assemblers for these systems which GAS must emulate. GAS also provides .balign and .p2align directives, described later, which have a consistent behavior across all architectures (but are specific to GAS).