To calculate the size of a structure, or the offset of a substructure.
But you can do that on the M68k:
SUBA.L <ea>,An
<ea> can be any addressing mode, including another address register. Most assemblers will let you use SUB.L and substitute SUBA if the destination is an address register.
But you can do that on the M68k:
<ea> can be any addressing mode, including another address register. Most assemblers will let you use SUB.L and substitute SUBA if the destination is an address register.