.p2align[wl]

Previous Assembler Directives Next

Syntax: .p2align[wl] alignment[, [fill][, max]]

Pad the location counter (in the current subsection) to a particular storage boundary. alignment (which must be absolute) is the number of low-order zero bits the location counter must have after advancement. For example .p2align 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.

fill (also absolute) gives the fill value to be stored in the padding bytes. It (and the comma) may be omitted. If it is omitted, the padding bytes are normally zero. However, on some systems, if the section is marked as containing code and the fill value is omitted, the space is filled with no-op instructions (I didn't checked whether this is the case in TIGCC).

max is also absolute, and is also optional. If it is present, it is the maximum number of bytes that should be skipped by this alignment directive. If doing the alignment would require skipping more bytes than the specified maximum, then the alignment is not done at all. You can omit the fill value (the second argument) entirely by simply using two commas after the required alignment; this can be useful if you want the alignment to be filled with no-op instructions when appropriate.

The .p2alignw and .p2alignl directives are variants of the .p2align directive. The .p2alignw directive treats the fill pattern as a two byte word value. The .p2alignl directives treats the fill pattern as a four byte longword value. For example, .p2alignw 2,0x368d will align to a multiple of 4. If it skips two bytes, they will be filled in with the value 0x368d (the exact placement of the bytes depends upon the endianness of the processor). If it skips 1 or 3 bytes, the fill value is undefined.


See also: .balign