exp is an expression in the current language.
This is similar to print, but does not echo the results. This should be used instead of print when performing I/O accesses since printing the result of exp may cause an extra read of the I/O address. For example,
eval *(int * ) 0xffffa0c0 = 0x123 |
If you are concerned about accessing I/O memory, see also the system variable _CACHE.