macro_rules! sload { ($interp:expr, $host:expr, $address:expr, $index:expr) => { ... }; }
Performs an SLOAD on the target account and storage index.
SLOAD
If the slot could not be loaded, or if the gas cost could not be charged, the expanded code sets the instruction result and returns accordingly.
This macro charges gas.
Expands to the value of the storage slot.