Function fragment_read_gas 

pub fn fragment_read_gas(warm: bool, code_size: u64) -> u64

Gas charged for reading one fragment of code_size bytes during activation, matching fragmentReadGasCost: a cold (or warm) account access plus the per-word copy cost. The fragment-read charger uses this for both the preflight affordability check (against the max code size) and the actual per-fragment charge.