in R: how to take value from i+1th row of 1 dataframe and subtract from every row in i+1th column of 2nd dataframe

Note that the actual dataset is 1000s of columns and 100s of rows so I am looking for a way that does not require that i manually name either columns or rows.

With a dataset that has similar structure as follows:

subvalues <- c(1:10)

df <- data.frame(x = rpois(40,2), y = rpois(40,2), z = rpois(40,2), q = rpois(40,2), t = rpois(40,2))

call the rows of subvalues SVa, SVb, SVc...
call the rows of the dataframe's columns Xa, Xb, Xc... Ya, Yb, Yc... etc.

What I am trying to build is the following: A function that takes first the first cell of subvalues (SVa) and subtracts it from every row in column X (Xa, Xb, Xc, etc.), 2nd to take the 2nd cell of subvalues (SVb) and subtract it from every row in column y (Ya, Yb, Yc, etc.)

What I have so far is:

res <- numeric(length = length(x))  
for (i in seq_along(x)) {  
  res[i] <- xpos - [**SVi+1**] 
}  
res  

I need to figure out the 'SVi+1' loop and how to properly do the loop-within a loop.

Any help is much appreciated