There are various ways to do this. Note that there is little obvious point to creating a new variable just to hold one constant. Code not tested.
forval i = 1/8 {
local j = `i' + 1
capture test _b[`i'.ordinal] - _b[`j'.ordinal] = 0
if _rc == 0 {
local sign = sign(_b[`i'.ordinal] - _b[`j'.ordinal])
display "Ho: `i' <= `j' p-value = " ttail(r(df_r), `sign' * sqrt(r(F)))
display "Ho: `i' >= `j' p-value = " 1-ttail(r(df_r), `sign' * sqrt(r(F)))
}
}
The capture
should eat errors.