Even though it looks longer, this should end up almost twice as fast...
Code:
outvar = 0
if (invar.0) then
    outvar.0 = 1
    outvar.1 = 1
endif
if (invar.1) then
    outvar.2 = 1
    outvar.3 = 1
endif
if (invar.2) then
    outvar.4 = 1
    outvar.5 = 1
endif
if (invar.3) then
    outvar.6 = 1
    outvar.7 = 1
endif
if (invar.4) then
    outvar.8 = 1
    outvar.9 = 1
endif
if (invar.5) then
    outvar.10 = 1
    outvar.11 = 1
endif
if (invar.6) then
    outvar.12 = 1
    outvar.13 = 1
endif
if (invar.7) then
    outvar.14 = 1
    outvar.15 = 1
endif