O1
#define r_A O1
[BPF_REG_2] = O1,
emit_reg_move(I1, O1, ctx);
unsigned long O1, min_err, rate_err;
O1 = rate * *divisor1 * (1 << (*divisor2));
rate_err = O1 % parent_rate;
*multiplier = O1 / parent_rate;