The M88K version of the assembler supports the following machine directives:

.align: This directive aligns the section program counter on the next 4-byte boundary.
.dfloat expr: This assembles a double precision (64-bit) floating point constant.
.ffloat expr: This assembles a single precision (32-bit) floating point constant.
.half expr: This directive assembles a half-word (16-bit) constant.
.word expr: This assembles a word (32-bit) constant.
.string "str": This directive behaves like the standard .ascii directive for copying str into the object file. The string is not terminated with a null byte.
.set symbol, value: This directive creates a symbol named symbol which is an alias for another symbol (possibly not yet defined). This should not be confused with the mnemonic set, which is a legitimate M88K instruction.
.def symbol, value: This directive is synonymous with .set and is presumably provided for compatibility with other M88K assemblers.
.bss symbol, length, align: Reserve length bytes in the bss section for a local symbol, aligned to the power of two specified by align. length and align must be positive absolute expressions. This directive differs from .lcomm only in that it permits you to specify an alignment. See .lcomm.