SB, SH, SW, SD — stores

sb rs2, offset(rs1)
sh rs2, offset(rs1)
sw rs2, offset(rs1)
sd rs2, offset(rs1)    # RV64 only

Stores write the low 8, 16, 32, or 64 bits of rs2. They do not modify either register.

sd ra, 24(sp)
sw a0, 0(a1)

x86 connection: closest to mov [base + displacement], src, but base-plus-index addressing must be calculated separately.