GNU assembler padding

[moth]

I'm converting my boot sector code over to GNU assembler for consistency, and I can't seem to find how to pad the binary to 510 bytes + signature.  Anyone know the correct padding directive and how to use it?  Thanks

[moth]

I think I figured it out.  We'll see if it breaks when I get all the code ported:

------------------------------------------
boot_start:
     ...
boot_end:
     .space (510 - (boot_end - boot_start)),0x00
     .byte 0x55,0xAA