.struct 0 field1: .struct field1 + 4 field2: .struct field2 + 4 field3:
This would define the symbol
field1 to have the value 0, the symbol
field2 to have the value 4, and the symbol
field3 to have the
value 8. Assembly would be left in the absolute section, and you would need to
.section directive of some sort to change to some other section
before further assembly.