solana_rbpf::ebpf
pub const ST_B_REG: u8 = BPF_STX | BPF_MEM | BPF_B; // 115u8
BPF opcode: stxb [dst + off], src /// (dst + offset) as u8 = src.
stxb [dst + off], src
(dst + offset) as u8 = src